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A
TREATISE
ON
ANATOMY, PHYSIOLOGY,
AND HYGIENE
DESIGNED FOR
COLLEGES, ACADEMIES, AND FAMILIES.
BY CALVIN CUTTER, M.D.
-----
WITH ONE HUNDRED AND FIFTY ENGRAVINGS.
-----
REVISED STEREOTYPE EDITION.
NEW YORK:
CLARK, AUSTIN AND SMITH.
CINCINNATI:--W. B. SMITH & CO.
ST. LOUIS, MO.:--KEITH & WOODS.
1858.
Entered according to Act of Congress, in the year 1852, by
CALVIN CUTTER, M. D.,
In the Clerk's Office of the District Court of the District
of Massachusetts.
C. A. ALVORD, Printer,
No. 15 Vandewater Street, N. Y.
PREFACE.
Agesilaus, king of Sparta, when asked what things boys should learn,
replied, "Those which they will _practise_ when they become men." As
health requires the observance of the laws inherent to the different
organs of the human system, so not only boys, but girls, should
acquire a knowledge of the laws of their organization. If sound
morality depends upon the inculcation of correct principles in youth,
equally so does a sound physical system depend on a correct physical
education during the same period of life. If the teacher and parents
who are deficient in moral feelings and sentiments, are unfit to
communicate to children and youth those high moral principles demanded
by the nature of man, so are they equally incompetent directors of the
physical training of the youthful system, if ignorant of the organic
laws and the physiological conditions upon which health and disease
depend.
For these reasons, the study of the structure of the human system, and
the laws of the different organs, are subjects of interest to
all,--the young and the old, the learned and the unlearned, the rich
and the poor. Every scholar, and particularly every young miss, after
acquiring a knowledge of the primary branches,--as spelling, reading,
writing, and arithmetic,--should learn the structure of the human
system, and the conditions upon which health and disease depend, as
this knowledge will be required in _practice_ in after life.
"It is somewhat unaccountable," says Dr. Dick, "and not a little
inconsistent, that while we direct the young to look abroad over the
surface of the earth, and survey its mountains, rivers, seas, and
continents, and guide their views to the regions of the firmament,
where they may contemplate the moons of Jupiter, the rings of Saturn,
and thousands of luminaries placed at immeasurable distances, ... that
we should never teach them _to look into themselves_; to consider
their own corporeal structures, the numerous parts of which they are
composed, the admirable functions they perform, the wisdom and
goodness displayed in their mechanism, and the lessons of practical
instruction which may be derived from such contemplations."
Again he says, "One great practical end which should always be kept in
view in the study of physiology, is the invigoration and improvement
of the corporeal powers and functions, the preservation of health, and
the prevention of disease."
The design of the following pages is, to diffuse in the community,
especially among the youth, a knowledge of Human Anatomy, Physiology,
and Hygiene. To make the work clear and practical, the following
method has been adopted:--
1st. The structure of the different organs of the system has been
described in a clear and concise manner. To render this description
more intelligible, one hundred and fifty engravings have been
introduced, to show the situation of the various organs. Hence the
work may be regarded as an elementary treatise on anatomy.
2d. The functions, or uses of the several parts have been briefly and
plainly detailed; making a primary treatise on human physiology.
3d. To make a knowledge of the structure and functions of the
different organs _practical_, the laws of the several parts, and the
conditions on which health depends, have been clearly and succinctly
explained. Hence it may be called a treatise on the principles of
hygiene, or health.
To render this department more complete, there has been added the
appropriate treatment for burns, wounds, hemorrhage from divided
arteries, the management of persons asphyxiated from drowning,
carbonic acid, or strangling, directions for nurses, watchers, and the
removal of disease, together with an Appendix, containing antidotes
for poisons, so that persons may know what _should be done_, and what
_should not be done_, until a surgeon or physician can be called.
In attempting to effect this in a brief elementary treatise designed
for schools and families, it has not been deemed necessary to use
vulgar phrases for the purpose of being understood. The appropriate
scientific term should be applied to each organ. No more effort is
required to learn the meaning of a _proper_, than an improper term.
For example: a child will pronounce the word as readily, and obtain as
correct an idea, if you say _lungs_, as if you used the word _lights_.
A little effort on the part of teachers and parents, would diminish
the number of vulgar terms and phrases, and, consequently, improve the
language of our country. To obviate all objections to the use of
proper scientific terms, a Glossary has been appended to the work.
The author makes no pretensions to new discoveries in physiological
science. In preparing the anatomical department, the able treatises of
Wilson, Cruveilhier, and others have been freely consulted. In the
physiological part, the splendid works of Carpenter, Dunglison,
Liebig, and others have been perused. In the department of hygiene
many valuable hints have been obtained from the meritorious works of
Combe, Rivers, and others.
We are under obligations to R. D. Mussey, M. D., formerly Professor of
Anatomy and Surgery, Dartmouth College, N. H., now Professor of
Surgery in the Ohio Medical College; to J. E. M'Girr, A. M., M. D.,
Professor of Anatomy, Physiology, and Chemistry, St. Mary's
University, Ill.; to E. Hitchcock, Jr., A. M., M. D., Teacher of
Chemistry and Natural History, Williston Seminary, Mass.; to Rev. E.
Hitchcock, D. D., President of Amherst College, Mass., who examined
the revised edition of this work, and whose valuable suggestions
rendered important aid in preparing the manuscript for the present
stereotype edition.
We return our acknowledgments for the aid afforded by the Principals
of the several Academies and Normal Schools who formed classes in
their institutions, and examined the revised edition as their pupils
progressed, thus giving the work the best possible test trial, namely,
the recitation-room.
To the examination of an intelligent public, the work is respectfully
submitted by
CALVIN CUTTER.
WARREN, MASS., _Sept. 1, 1852_.
TO TEACHERS AND PARENTS.
As the work is divided into chapters, the subjects of which are
complete in themselves, the pupil may commence the study of the
structure, use, and laws of the several parts of which the human
system is composed, by selecting such chapters as fancy or utility may
dictate, without reference to their present arrangement,--as well
commence with the chapter on the digestive organs as on the bones.
The acquisition of a correct pronunciation of the technical words is
of great importance, both in recitation and in conversation. In this
work, the technical words interspersed with the text, have been
divided into syllables, and the accented syllables designated. An
ample Glossary of technical terms has also been appended to the work,
to which reference should be made.
It is recommended that the subject be examined in the form of
_topics_. The questions in _Italics_ are designed for this method of
recitation. The teacher may call on a pupil of the class to describe
the anatomy of an organ from an anatomical outline plate; afterwards
call upon another to give the physiology of the part, while a third
may state the hygiene, after which, the questions at the bottom of
the page may be asked promiscuously, and thus the detailed knowledge
of the subject possessed by the pupils will be tested.
At the close of the chapters upon the Hygiene of the several portions
of the system, it is advised that the instructor give a lecture
reviewing the anatomy, physiology, and hygiene, of the topic last
considered. This may be followed by a general examination of the class
upon the same subject. By this course a clear and definite knowledge
of the mutual relation of the Anatomy, Physiology, and Hygiene, of
different parts of the human body, will be presented.
We also suggest the utility of the pupils' giving analogous
illustrations, examples, and observations, where these are interspersed
in the different chapters, not only to induce inventive thought, but to
discipline the mind.
To parents and others we beg leave to say, that about two thirds of
the present work is devoted to a concise and practical description of
the uses of the important organs of the human body, and to show how
such information may be usefully applied, both in the preservation of
health, and the improvement of physical education. To this have been
added directions for the treatment of those accidents which are daily
occurring in the community, making it a treatise proper and profitable
for the FAMILY LIBRARY, as well as the school-room.
CONTENTS.
Chapter. Page.
1. General Remarks, 13
2. Structure of Man, 17
3. Chemistry of the Human Body, 25
4. Anatomy of the Bones, 29
5. Anatomy of the Bones, continued, 39
6. Physiology of the Bones, 48
7. Hygiene of the Bones, 53
8. Anatomy of the Muscles, 64
9. Physiology of the muscles, 76
10. Hygiene of the Muscles, 85
11. Hygiene of the Muscles, continued, 96
12. Anatomy of the Teeth, 105
12. Physiology of the Teeth, 109
12. Hygiene of the Teeth, 110
13. Anatomy of the Digestive Organs, 113
14. Physiology of the Digestive Organs, 124
15. Hygiene of the Digestive Organs, 129
16. Hygiene of the Digestive Organs, continued, 142
17. Anatomy of the Circulatory Organs, 154
18. Physiology of the Circulatory Organs, 164
19. Hygiene of the Circulatory Organs, 172
20. Anatomy of the Lymphatic Vessels, 181
20. Physiology of the Lymphatic Vessels, 183
20. Hygiene of the Lymphatic Vessels, 188
21. Anatomy of the Secretory Organs. 192
21. Physiology of the Secretory Organs, 193
21. Hygiene of the Secretory Organs, 197
22. Nutrition, 200
22. Hygiene of Nutrition, 205
23. Anatomy of the Respiratory Organs, 209
24. Physiology of the Respiratory Organs, 217
25. Hygiene of the Respiratory Organs, 228
26. Hygiene of the Respiratory Organs, continued, 239
27. Animal Heat, 252
28. Hygiene of Animal Heat, 261
29. Anatomy of the Vocal Organs, 268
29. Physiology of the Vocal Organs, 272
30. Hygiene of the Vocal Organs, 274
31. Anatomy of the Skin, 282
32. Physiology of the Skin, 293
33. Hygiene of the Skin, 301
34. Hygiene of the Skin, continued, 311
35. Appendages of the Skin, 322
36. Anatomy of the Nervous System, 327
37. Anatomy of the Nervous System, continued, 340
38. Physiology of the Nervous System, 346
39. Hygiene of the Nervous System, 358
40. Hygiene of the Nervous System, continued, 368
41. The Sense of Touch, 378
42. Anatomy of the Organs of Taste, 384
42. Physiology of the Organs of Taste, 386
43. Anatomy of the Organs of Smell, 389
43. Physiology of the Organs of Smell, 391
44. Anatomy of the Organs of Vision, 394
45. Physiology of the Organs of Vision, 404
45. Hygiene of the Organs of Vision, 410
46. Anatomy of the Organs of Hearing, 414
47. Physiology of the Organs of Hearing, 420
47. Hygiene of the Organs of Hearing, 422
48. Means of preserving the Health, 425
49. Directions for Nurses, 432
- - - - -
APPENDIX, 439
GLOSSARY, 451
INDEX, 463
ANATOMY, &c.
CHAPTER I.
GENERAL REMARKS.
1. ANATOMY is the science which treats of the structure and relations
of the different parts of animals and plants.
2. It is divided into _Vegetable_ and _Animal_ anatomy. The latter of
these divisions is subdivided into _Human_ anatomy, which considers,
exclusively, human beings; and _Comparative_ anatomy, which treats of
the mechanism of the lower orders of animals.
3. PHYSIOLOGY treats of the functions, or uses of the organs of
animals and plants. Another definition is, "the science of life."
4. This is also divided into _Vegetable_ and _Animal_ physiology, as
it treats of the vegetable or animal kingdom; and into _Human_ and
_Comparative_ physiology, as it describes the vital functions of man
or the inferior animals.
5. HYGIENE is the art or science of maintaining health, or a knowledge
of those laws by which health may be preserved.
6. The kingdom of nature is divided into _organic_ and _inorganic_
bodies. Organic bodies possess organs, on whose action depend their
growth and perfection. This division includes animals and plants.
Inorganic bodies are devoid of organs, or instruments of life. In this
division are classed the earths, metals, and other minerals.
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1. What is anatomy? 2. How is it divided? How is the latter division
subdivided? 3. What is physiology? Give another definition. 4. How is
physiology divided? Give a subdivision. 5. What is hygiene? 6. Define
organic bodies.
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7. In general, organic matter differs so materially from inorganic,
that the one can readily be distinguished from the other. In the
organic world, every individual of necessity springs from some
_parent, or immediate producing agent_; for while inorganic substances
are formed by chemical laws alone, we see no case of an animal or
plant coming into existence by accident or chance, or chemical
operations.
8. Animals and plants _are supported by means of nourishment_, and die
without it. They also increase in size _by the addition of new
particles of matter to all parts of their substances_; while rocks and
minerals grow only by additions to their surfaces.
9. "Organized bodies always present a combination of both solids and
fluids;--of solids, differing in character and properties, arranged
into organs, and these endowed with functional powers, and so
associated as to form of the whole a single system;--and of fluids,
contained in these organs, and holding such relation to the solids
that the existence, nature, and properties of both mutually and
necessarily depend on each other."
10. Another characteristic is, that organic substances have a _certain
order of parts_. For example, plants possess organs to gain
nourishment from the soil and atmosphere, and the power to give
strength and increase to all their parts. And animals need not only a
digesting and circulating apparatus, but organs for breathing, a
nervous system, &c.
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6. Define inorganic bodies. 7. What is said of the difference, in
general, between organic and inorganic bodies? 8. What of the growth
of organic and inorganic bodies? 9. What do organized bodies always
present? 10. Give another characteristic of organized substances.
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11. _Individuality_ is an important characteristic. For instance, a
large rock may be broken into a number of smaller pieces, and yet
every fragment will be rock; but if an organic substance be separated
into two or more divisions, neither of them can be considered an
individual. Closely associated with this is the power of _life_, or
_vitality_, which is the most distinguishing characteristic of organic
structure; since we find nothing similar to this in the inorganic
creation.
12. _The distinction between plants and animals_ is also of much
importance. _Animals grow proportionally in all directions_, while
plants grow upwards and downwards from a collet only. The _food_ of
animals is _organic_, while that of plants is _inorganic_; the latter
feeding entirely upon the elements of the soil and atmosphere, while
the former subsist upon the products of the animal and vegetable
kingdoms. The size of the vegetable is in most cases limited only by
the duration of existence, as a tree continues to put forth new
branches during each period of its life, while the animal, at a
certain time of life, attains the average size of its species.
13. One of the most important distinctions between animals and plants,
is _the different effects of respiration_. Animals consume the oxygen
of the atmosphere, and give off carbonic acid; while plants take up
the carbonic acid, and restore to animals the oxygen, thus affording
an admirable example of the principle of compensation in nature.
14. But the decisive distinctions between animals and plants are
_sensation_ and _voluntary motion_, the power of acquiring a knowledge
of external objects through the senses, and the ability to move from
place to place at will. These are the characteristics which, in their
fullest development in man, show intellect and reasoning powers, and
thereby in a greater degree exhibit to us the wisdom and goodness of
the Creator.
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11. What is said of the individuality of organized and inorganized
bodies? What is closely associated with this? 12. Give a distinction
between animals and plants as regards growth. The food of animals and
plants. What is said in respect to size? 13. What important
distinction in the effects of respiration of animals and plants? 14.
What are the decisive distinctions between animals and plants?
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15. DISEASE, which consists in an unnatural condition of the bodily
organs, is in most cases under the control of fixed laws, which we are
capable of understanding and obeying. Nor do diseases come by chance;
they are penalties for violating physical laws. If we carelessly cut
or bruise our flesh, pain and soreness follow, to induce us to be more
careful in the future; or, if we take improper food into the stomach,
we are warned, perhaps immediately by a friendly pain, that we have
violated an organic law.
16. Sometimes, however, the penalty does not directly follow the sin,
and it requires great physiological knowledge to be able to trace the
effect to its true cause. If we possess good constitutions, we are
responsible for most of our sickness; and bad constitutions, or
hereditary diseases, are but the results of the same great law,--the
iniquities of the parents being visited on the children. In this view
of the subject, how important is the study of physiology and hygiene!
For how can we expect to obey laws which we do not understand?
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15. What is said of disease? 16. Why is the study of physiology and
hygiene important?
-=-=-=-=-=-=-=-=-=-=-=-=
CHAPTER II.
STRUCTURE OF MAN,
17. In the structure of the human body, there is a union of fluids and
solids. These are essentially the same, for the one is readily changed
into the other. There is no fluid that does not contain solid matter
in solution, and no solid matter that is destitute of fluid.
18. In different individuals, and at different periods of life the
proportion of fluids and solids varies. In youth, the fluids are more
abundant than in advanced life. For this reason, the limbs in
childhood are soft and round, while in old age they assume a hard and
wrinkled appearance.
19. The fluids not only contain the materials from which every part of
the body is formed, but they are the medium for conveying the waste,
decayed particles of matter from the system. They have various names,
according to their nature and function; as, the blood, and the bile.
20. The solids are formed from the fluids, and consequently they are
reduced, by chemical analysis, to the same ultimate elements. The
particles of matter in solids are arranged variously; sometimes in
_fi'bres_, (threads,) sometimes in _lam'i-nae_, (plates,) sometimes
homogeneously, as in basement membranes. (Appendix A.)
21. The parts of the body are arranged into _Fi'bres_, _Fas-cic'u-li_,
_Tis'sues_, _Or'gans_, _Ap-pa-ra'tus-es_, and _Sys'tems_.
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17. What substances enter into the structure of the human body? Are
they essentially the same? 18. What is said of these substances at
different periods of life? 19. What offices do the fluids of the
system perform? 20. What is said of the solids? How are the particles
of matter arranged in solids? 21. Give an arrangement of the parts of
the body.
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22. A FIBRE is a thread of exceeding fineness. It is either
cylindriform or flattened.
23. A FASCICULUS is the term applied to several fibres united. Its
general characteristics are the same as fibres.
24. A TISSUE is a term applied to several different solids of the
body.
25. An ORGAN is composed of tissues so arranged as to form an
instrument designed for action. The action of an organ is called its
_function_, or use.
_Example._ The liver is an organ, and the secretion of the bile from
the blood is one of its functions.[1]
[1] Where examples and observations are given or experiments
suggested, let the pupil mention other analogous ones.
26. An APPARATUS is an assemblage of organs designed to produce
certain results.
_Example._ The digestive apparatus consists of the teeth, stomach,
liver, &c., all of which aid in the digestion of food.
[Illustration: Fig. 2. Represents a portion of broken muscular fibre of
animal life, (magnified about seven hundred diameters.)]
27. The term SYSTEM is applied to an assemblage of organs arranged
according to some plan, or method; as the nervous system, the
respiratory system.
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22. Define a fibre. 23. Define a fasciculus. 24. Define a tissue. 25.
Define an organ. What is the action of an organ called? Give examples.
_Mention other examples._ 26. What is an apparatus? Give an example
27. How is the term system applied?
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28. A TISSUE is a simple form of organized animal substance. It is
flexible, and formed of fibres interwoven in various ways; as, the
cellular tissue.
29. However various all organs may appear in their structure and
composition, it is now supposed that they can be reduced to a few
tissues; as, the _Cel'lu-lar_, _Os'se-ous_, _Mus'cu-lar_, _Mu'cous_,
_Ner'vous_, &c. (Appendix B.)
30. The CELLULAR TISSUE,[2] now called the _areolar tissue_, consists
of small fibres, or bands, interlaced in every direction, so as to
form a net-work, with numerous interstices that communicate freely
with each other. These interstices are filled, during life, with a
fluid resembling the serum of blood. The use of the areolar tissue is
to connect together organs and parts of organs, and to envelop, fix,
and protect the vessels and nerves of organs.
[2] The _Cellular_, _Serous_, _Dermoid_, _Fibrous_, and _Mucous
tissues_ are very generally called _membranes_.
[Illustration: Fig. 3. Arrangement of fibres of the cellular tissue
magnified one hundred and thirty diameters.]
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28. What is a tissue? 29. What is said respecting the structure and
composition of the various organs? Name the primary membranes. 30.
Describe the cellular tissue. How are the cells imbedded in certain
tissues? Give observation 1st, relative to the cellular tissue.
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_Observations._ 1st. When this fluid becomes too great in quantity, in
consequence of disease, the patient labors under general dropsy. The
swelling of the feet when standing, and their return to a proper shape
during the night, so often noticed in feeble persons, furnish a
striking proof both of the existence and peculiarity of this tissue,
which allows the fluid to flow from cell to cell, until it settles in
the lower extremities.
2d. The free communication between the cells is still more remarkable
in regard to air. Sometimes, when an accidental opening has been made
from the air-cells of the lungs into the contiguous cellular tissue,
the air in respiration has penetrated every part until the whole body
is so inflated as to occasion suffocation. Butchers often avail
themselves of the knowledge of this fact, and inflate their meat to
give it a fat appearance.
31. "Although this tissue enters into the composition of all organs,
it never loses its own structure, nor participates in the functions of
the organ of which it forms a part. Though present in the nerves, it
does not share in their sensibility; and though it accompanies every
muscle and every muscular fibre, it does not partake of the
irritability which belongs to these organs."
32. Several varieties of tissue are formed from the cellular; as, the
_Se'rous_, _Der'moid_, _Fi'brous_, and several others.
33. The SEROUS TISSUE lines all the closed, or sac-like cavities of
the body; as, the chest, joints, and abdomen. It not only lines these
cavities, but is reflected, and invests the organs contained in them.
The liver and the lungs are thus invested. This membrane is of a
whitish color, and smooth on its free surfaces. These surfaces are
kept moist, and prevented from adhering by a _se'rous_ fluid, which is
separated from the blood. The use of this membrane is to separate
organs and also to facilitate the movement of one part upon another,
by means of its moist, polished surfaces.
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Give observation 2d. 31. What is said of the identity of this tissue?
32. Name the varieties of tissue formed from the cellular. 33. Where
is the serous tissue found? What two offices does it perform? Give its
structure. What is the use of this membrane?
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34. The DERMOID TISSUE covers the outside of the body. It is called
the _cu'tis_, (skin.) This membrane is continuous with the mucous at
the various orifices of the body, and in these situations, from the
similarity of their structure, it is difficult to distinguish between
them.
_Observations._ 1st. In consequence of the continuity and similarity
of structure, there is close sympathy between the mucous and dermoid
membranes. If the functions of the skin are disturbed, as by a chill,
it will frequently cause a catarrh, (cold,) or diarrhoea. Again, in
consequence of this intimate sympathy, these complaints can be
relieved by exciting a free action in the vessels of the skin.
2d. It is no uncommon occurrence that diseased or irritated conditions
of the mucous membrane of the stomach or intestines produce diseases
or irritations of the skin, as is seen in the rashes attendant on
dyspepsia, and eating certain species of fish. These eruptions of the
skin can be relieved by removing the diseased condition of the
stomach.
35. The FIBROUS TISSUE consists of longitudinal, parallel fibres,
which are closely united. These fibres, in some situations, form a
thin, dense, strong membrane, like that which lines the internal
surface of the skull, or invests the external surface of the bones.
In other instances, they form strong, inelastic bands, called
_lig'a-ments_, which bind one bone to another. This tissue also
forms _ten'dons_, (white cords,) by which the muscles are attached
to the bones.
_Observation._ In the disease called rheumatism, the fibrous tissue is
the part principally affected; hence the joints, where this tissue is
most abundant, suffer most from this affection.
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34. Describe the dermoid tissue. What is said of the sympathy between
the functions of the skin and mucous membrane? Give another instance
of the sympathy between these membranes. 35. Of what does the fibrous
tissue consist? How do these appear in some situations? How in others?
What tissue is generally affected in rheumatism?
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36. The ADIPOSE TISSUE is so arranged as to form distinct bags, or
cells. These contain a substance called _fat_. This tissue is
principally found beneath the skin, abdominal muscles, and around the
heart and kidneys; while none is found in the brain, eye, ear, nose,
and several other organs.
_Observation._ In those individuals who are corpulent, there is in
many instances, a great deposit of this substance. This tissue
accumulates more readily than others when a person becomes gross, and
is earliest removed when the system emaciates, in acute or chronic
diseases. Some of the masses become, in some instances, enlarged.
These enlargements are called _adipose_, or _fatty tumors_.
[Illustration: Fig. 4. 1, A portion of the adipose tissue. 2, 2, 2,
Minute bags containing fat. 3, A cluster of these bags, separated and
suspended.]
37. The CARTILAGINOUS TISSUE is firm, smooth, and highly elastic.
Except bone, it is the hardest part of the animal frame. It tips the
ends of the bones that concur in forming a joint. Its use is to
facilitate the motion of the joints by its smooth surface, while its
elastic character diminishes the shock that would otherwise be
experienced if this tissue were inelastic.
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36. Describe the adipose tissue. Where does this tissue principally
exist? Give observation in regard to the adipose tissue. 37. Describe
the cartilaginous tissue. What is its use?
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38 The OSSEOUS TISSUE, in composition and arrangement of matter,
varies at different periods of life, and in different bones. In some
instances, the bony matter is disposed in plates, while in other
instances, the arrangement is cylindrical. Sometimes, the bony matter
is dense and compact; again, it is spongy, or porous. In the centre of
the long bones, a space is left which is filled with a fatty
substance, called _mar'row_.
_Observation._ Various opinions exist among physiologists in regard to
the use of marrow. Some suppose it serves as a reservoir of
nourishment, while others, that it keeps the bones from becoming dry
and brittle. The latter opinion, however, has been called in question,
as the bones of the aged man contain more marrow than those of the
child, and they are likewise more brittle.
[Illustration: Fig. 5. A section of the femur, (thigh-bone.) 1, 1, The
extremities, showing a thin plate of compact texture, which covers small
cells, that diminish in size, but increase in number, as they approach
the articulation. 2, 2, The walls of the shaft, which are very firm and
solid. 3, The cavity that contains the marrow.]
39. The MUSCULAR TISSUE is composed of many fibres, that unite to form
fasciculi, each of which is enclosed in a delicate layer of cellular
tissue. Bundles of these fasciculi constitute a muscle.
_Observation._ A piece of boiled beef will clearly illustrate the
arrangement of muscular fibre.
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38. What is said of the osseous tissue? How is the bony matter
arranged in different parts of the animal frame? What is said of the
use of marrow? 39. Of what is the muscular tissue composed? How may
the arrangement of muscular fibre be illustrated?
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40. The MUCOUS TISSUE differs from the serous by its lining all
the cavities which communicate with the air. The nostrils, the
mouth, and the stomach afford examples. The external surface of this
membrane, or that which is exposed to the air, is soft, and bears some
resemblance to the downy rind of a peach. It is covered by a viscid
fluid called _mu'cus_. This is secreted by small _gland-cells_,
called _ep-i-the'li-a_, or secretory cells of the mucous membrane.
The use of this membrane and its secreted mucus is to protect the
inner surface of the cavities which it lines.
_Observation._ A remarkable sympathy exists between the remote parts
of the mucous membrane. Thus the condition of the stomach may be
ascertained by an examination of the tongue.
41. The NERVOUS TISSUE consists of soft, pulpy matter, enclosed in
a sheath, called _neu-ri-lem'a_. This tissue consists of two
substances. The one, of a pulpy character and gray color, is called
_cin-e-ri'tious_, (ash-colored.) The other, of a fibrous character and
white, is named _med'ul-la-ry_, (marrow-like.) In every part of the
nervous system both substances are united, with the exception of the
nervous fibres and filaments, which are solely composed of the
medullary matter enclosed in a delicate sheath.
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40. How does the mucous differ from the serous tissue? What is the
appearance of the external surface of this membrane? Where is the
mucus secreted? What is the use of this membrane? 41. Of what does the
nervous tissue consist? Describe the two substances that enter into
the composition of the nervous tissue.
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CHAPTER III
CHEMISTRY OF THE HUMAN BODY.
42. An ULTIMATE ELEMENT is the simplest form of matter with which we
are acquainted; as gold, iron, &c.
43. These elements are divided into _metallic_ and _non-metallic_
substances. The metallic substances are _Po-tas'si-um_, _So'di-um_,
_Cal'ci-um_, _Mag-ne'si-um_, _A-lu'min-um_, _I'ron_, _Man'ga-nese_, and
_Cop'per_. The non-metallic substances are _Ox'y-gen_, _Hy'dro-gen_,
_Car'bon_, _Ni'tro-gen_, _Si-li'-ci-um_, _Phos'phor-us_, _Sul'phur_,
_Chlo'rine_, and a few others.
44. POTASH (potassium united with oxygen) is found in the blood, bile,
perspiration, milk, &c.
45. SODA (sodium combined with oxygen) exists in the muscles, and in
the same fluids in which potash is found.
46. LIME (calcium combined with oxygen) forms the principal ingredient
of the bones. The lime in them is combined with phosphoric and
carbonic acid.
47. MAGNESIA (magnesium combined with oxygen) exists in the bones,
brain, and in some of the animal fluids; as milk.
48. SILEX (silicium combined with oxygen) is contained in the hair and
in some of the secretions.
49. IRON forms the coloring principle of the red globules of the
blood, and is found in every part of the system.
_Observation._ As metallic or mineral substances enter into the
ultimate elements of the body, the assertion that all minerals are
poisonous, however small the quantity, is untrue.
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42. What is an ultimate element? Give examples. 43. How are they
divided? Name the metallic substances. Name the non-metallic
substances. 44. What is said of potash? 45. Of soda? 46. Of lime? 47.
Of magnesia? 48. Of silex? 49. What forms the coloring principle of
the blood? What is said of mineral substances?
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50. OXYGEN is contained in all the fluids and solids of the body. It
is almost entirely derived from the inspired air and water. It is
expelled in the form of carbonic acid and water from the lungs and
skin. It is likewise removed in the other secretions.
51. HYDROGEN is found in all the fluids and in all the solids of
the body. It is derived from the food, as well as from water and
other drinks. It exists in the greatest abundance in the impure,
dark-colored blood of the system. It is removed by the agency of the
kidneys, skin, lungs, and other excretory organs.
52. CARBON is an element in the oil, fat, albumen, fibrin, gelatin,
bile, and mucus. This element likewise exists in the impure blood in
the form of carbonic acid gas. Carbon is obtained from the food, and
discharged from the system by the secretions and respiration.
53. NITROGEN is contained in most animal matter, but is most abundant
in fibrin. It is not contained in fat and a few other substances.
_Observation._ The peculiar smell of animal matter when burning is
owing to nitrogen. This element combined with hydrogen forms
_am-mo'ni-a_, (hartshorn,) when animal matter is in a state of
putrefaction.
54. PHOSPHORUS is contained in many parts of the system, but more
particularly in the bones. It is generally found in combination with
oxygen, forming _phosphoric acid_. The phosphoric acid is usually
combined with alkaline bases; as lime in the bones, forming phosphate
of lime.
55. SULPHUR exists in the bones, muscles, hair, and nails. It is
expelled from the system by the skin and intestines.
56. CHLORINE is found in the blood, gastric juice, milk, perspiration,
and saliva.
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50. What is said of oxygen? 51. Of hydrogen? 52. What is said of
carbon? 53. Of nitrogen? How is ammonia formed? 54. What is said of
phosphorus? 55. What is said of sulphur? 56. Of chlorine?
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57. PROXIMATE ELEMENTS are forms of matter that exist in organized
bodies in abundance, and are composed chiefly of oxygen, hydrogen,
carbon, and nitrogen, arranged in different proportions. They exist
already formed, and may be separated in many instances, by heat or
mechanical means. The most important compounds are _Al-bu'men_,
_Fi'brin_, _Gel'a-tin_, _Mu'cus_, _Fat_, _Ca'se-ine_, _Chon'drine_,
_Lac'tic acid_, and _Os'ma-zome_.
58. ALBUMEN is found in the body, both in a fluid and solid form. It
is an element of the skin, glands, hair, and nails, and forms the
principal ingredient of the brain. Albumen is without color, taste, or
smell, and it coagulates by heat, acids, and alcohol.
_Observation._ The white of an egg is composed of albumen, which can
be coagulated or hardened by alcohol. As albumen enters so largely
into the composition of the brain, is not the impaired intellect and
moral degradation of the inebriate attributable to the effect of
alcohol in hardening the albumen of this organ?
59. FIBRIN exists abundantly in the blood, chyle, and lymph. It
constitutes the basis of the muscles. Fibrin is of a whitish color,
inodorous, and insoluble in cold water. It differs from albumen by
possessing the property of coagulating at all temperatures.
_Observation._ Fibrin may be obtained by washing the thick part of
blood with cold water; by this process, the red globules, or coloring
matter, are separated from this element.
60. GELATIN is found in nearly all the solids, but it is not known to
exist in any of the fluids. It forms the basis of the cellular tissue,
and exists largely in the skin, bones, ligaments, and cartilages.
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57. What are proximate elements? Do they exist already formed in
organized bodies? Name the most important compounds. 58. What is said
of albumen? Give observation relative to this element. 59. Of fibrin?
How does albumen differ from fibrin? How can fibrin be obtained? 60.
What is said of gelatin?
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_Observation._ Gelatin is known from other organic principles by its
dissolving in warm water, and forming "jelly." When dry, it forms the
hard, brittle substance, called _glue_. Isinglass, which is used in
the various mechanical arts, is obtained from the sounds of the
sturgeon.
61. MUCUS is a viscid fluid secreted by the gland-cells, or epithelia.
Various substances are included under the name of mucus. It is
generally alkaline, but its true chemical character is imperfectly
understood. It serves to moisten and defend the mucous membrane. It is
found in the cuticle, brain, and nails; and is scarcely soluble in
water, especially when dry. (Appendix C.)
62. OSMAZOME is a substance of an aromatic flavor. It is of a
yellowish-brown color, and is soluble both in water and alcohol, but
does not form a jelly by concentration. It is found in all the fluids,
and in some of the solids; as the brain.
_Observation._ The characteristic odor and taste of soup are owing to
osmazome.
63. There are several acids found in the human system; as the
_A-ce'tic_, _Ben-zo'ic_, _Ox-al'ic_, _U'ric_, and some other
substances, but not of sufficient importance to require a particular
description.
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How is it known from other organic principles? 61. What is said of
mucus? 62. Of osmazome? To what are the taste and odor of soup owing?
63. What acids are found in the system?
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CHAPTER IV.
THE BONES.
64. The bones are firm and hard, and of a dull white color. In all the
higher orders of animals, among which is man, they are in the interior
of the body, while in lobsters, crabs, &c., they are on the outside,
forming a case which protects the more delicate parts from injury.
65. In the mechanism of man, the variety of movements he is called to
perform requires a correspondent variety of component parts, and the
different bones of the system are so admirably adapted to each other,
that they admit of numerous and varied motions.
66. When the bones composing the skeleton are united by natural
ligaments, they form what is called a _natural skeleton_, when united
by wires, what is termed an _artificial skeleton_.
67. The elevations, or protuberances, of the bones are called
_proc'es-ses_, and are, generally, the points of attachment for the
muscles and ligaments.
ANATOMY OF THE BONES.
68. The BONES are composed of both animal and earthy matter. The
earthy portion of the bones gives them solidity and strength, while
the animal part endows them with vitality.
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64. What is said of the bones? 65. Is there an adaptation of the bones
of the system to the offices they are required to perform? 66. What is
a natural skeleton? What an artificial? 67. What part of the bones are
called processes? 68-73. _Give the structure of the bones._ 68. Of
what are the bones composed? What are the different uses of the
component parts of the bones?
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_Experiments._ 1st. To show the earthy without the animal matter, burn
a bone in a clear fire for about fifteen minutes, and it becomes white
and brittle, because the gelatin, or animal matter of the bone, has
been destroyed.
2d. To show the animal without the earthy matter of the bones, immerse
a slender bone for a few days in a weak acid, (one part muriatic acid
and six parts water,) and it can then be bent in any direction. In
this experiment, the acid has removed the earthy matter, (carbonate
and phosphate of lime,) yet the form of the bone is unchanged.
69. The bones are formed from the blood, and are subjected to several
changes before they are perfected. At their early formative stage,
they are cartilaginous. The vessels of the cartilage, at this period,
convey only the _lymph_, or white portion of the blood; subsequently,
they convey red blood. At this time, true ossification (the deposition
of phosphate and carbonate of lime) commences at certain points, which
are called _the points of ossification_.
70. Most of the bones are formed of several pieces, or centres of
ossification. This is seen in the long bones which have their
extremities separated from the body by a thin partition of cartilage.
It is some time before these separate pieces are united to form one
bone.
71. When the process of ossification is completed, there is still a
constant change in the bones. They increase in bulk, and become less
vascular, until middle age. In advanced life, the elevations upon
their surface and near the extremities become more prominent,
particularly in individuals accustomed to labor. As a person advances
in years, the vitality diminishes, and in extreme old age, the earthy
substance predominates; consequently, the bones are extremely
brittle.
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How can the earthy matter of the bones be shown? The animal? 69.
What is the appearance of the bones in their early formative stage?
When does true ossification commence? 70. How are most of the bones
formed? 71. What is said of the various changes of the bones after
ossification?
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72. The fibrous membrane that invests the bones is called
_per-i-os'te-um_; that which covers the cartilages is called
_per-i-chon'dri-um_. When this membrane invests the skull, it is
called _per-i-cra'ni-um_.
[Illustration: Fig. 6. A section of the knee-joint. The lower part of the
femur, (thigh-bone,) and upper part of the tibia, (leg-bone,) are seen
ossified at 1, 1. The cartilaginous extremities of the two bones are seen
at _d_, _d_. The points of ossification of the extremities, are seen at
2, 2. The patella, or knee-pan, is seen at _c_. 3, A point, or centre of
ossification.]
73. The PERIOSTEUM is a firm membrane immediately investing the bones,
except where they are tipped with cartilage, and the crowns of the
teeth, which are protected by enamel. This membrane has minute nerves,
and when healthy, possesses but little sensibility. It is the
nutrient membrane of the bone, endowing its exterior with vitality; it
also gives insertion to the tendons and connecting ligaments of the
joints.
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72. What is the membrane called that invests the bones? That covers
the cartilage? That invests the skull? Explain fig. 6. 73. Describe
the periosteum.
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74. There are two hundred and eight[3] bones in the human body,
beside the teeth. These, for convenience, are divided into four
parts: 1st. The bones of the _Head_. 2d. The bones of the _Trunk_.
3d. The bones of the _Upper Extremities_. 4th. The bones of the
_Lower Extremities_.
[3] Some anatomists reckon more than this number, others less, for
the reason that, at different periods of life, the number of
pieces of which one bone is formed, varies. _Example._ The
breast-bone, in infancy, has _eight_ pieces; in youth, _three_;
in old age, but _one_.
75. The bones of the HEAD are divided into those of the _Skull_,
_Ear_, and _Face_.
76. The SKULL is composed of eight bones. They are formed of two
plates, or tablets of bony matter, united by a porous portion of bone.
The external tablet is fibrous and tough; the internal plate is dense
and hard, and is called the _vit're-ous_, or glassy table. These
tough, hard plates are adapted to resist the penetration of sharp
instruments, while the different degrees of density possessed by the
two tablets, and the intervening spongy bone, serve to diminish the
vibrations that would occur in falls or blows.
77. The skull is convex externally, and at the base much thicker than
at the top or sides. The most important part of the brain is placed
here, completely out of the way of injury, unless of a very serious
nature. The base of the cranium, or skull, has many projections,
depressions, and apertures; the latter affording passages for the
nerves and blood-vessels.
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74. How many bones in the human body? How are they divided? 75-81.
_Give the anatomy of the bones of the head._ 75. How are the bones of
the head divided? 76. Describe the bones of the skull. 77. What is the
form of the skull? What does the base of the skull present?
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78. The bones of the cranium are united by ragged edges, called
_sut'ures_. The edges of each bone interlock with each other,
producing a union, styled, in carpentry, _dovetailing_. They
interrupt, in a measure, the vibrations produced by external blows,
and also prevent fractures from extending as far as they otherwise
would, in one continued bone. From infancy to the twelfth year, the
sutures are imperfect; but, from that time to thirty-five or forty,
they are distinctly marked; in old age, they are nearly obliterated.
[Illustration: Fig. 7. 1, 1, The coronal suture at the front and upper
part of the skull, or cranium. 2, The sagittal suture on the top of the
skull. 3, 3, The lambdoidal suture at the back part of the cranium.]
79. We find as great a diversity in the form and texture of the
skull-bone, as in the expression of the face. The head of the New
Hollander is small; that of the African is compressed; while the
Caucasian is distinguished for the beautiful oval form of the head.
The Greek skulls, in texture, are close and fine, while the Swiss are
softer and more open.
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78. How are the bones of the skull united? What are the uses of the
sutures? Mention the appearance of the sutures at different ages. What
does fig. 7 represent? 79. What is said respecting the form and
texture of the skull in different nations?
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80. In each EAR are four very small bones. They aid in hearing.
81. In the FACE are fourteen bones, some of which serve for the
attachment of powerful muscles, which are more or less called into
action in masticating food; others retain in place the soft parts of
the face.
[Illustration: Fig. 8. 1, The frontal, or bone of the forehead. 2. The
parietal bone. 3, The temporal bone. 4, The zygomatic process of the
temporal bone. 5, The malar (cheek) bone. 6, The superior maxillary bone,
(upper jaw.) 7, The vomer, that separates the cavities of the nose. 8,
The inferior maxillary bone, (lower jaw.) 9. The cavity for the eye.]
82. The TRUNK has fifty-four bones--twenty-four _Ribs_; twenty-four
bones in the _Spi'nal Col'umn_, (back-bone;) four in the _Pel'vis_;
the _Ster'num_, (breast-bone;) and the _Os hy-oid'es_, (the bone at
the base of the tongue.) They are so arranged as to form, with the
soft parts attached to them, two cavities, called the _Tho'rax_
(chest) and _Ab-do'men_.
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80. How many bones in the ear? 81. How many bones in the face? What is
their use? Explain fig. 8. 82-94. _Give the anatomy of the bones of
the trunk._ 82. How many bones in the trunk? Name them. What do they
form by their arrangement?
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83. The THORAX is formed by the sternum in front; the ribs, at the
sides; and the twelve dorsal bones of the spinal column, posteriorly.
The natural form of the chest is a cone, with its apex above; but
fashion, in many instances, has nearly inverted this order. This
cavity contains the lungs, heart, and large blood-vessels.
[Illustration: Fig. 9. 1, The first bone of the sternum, (breast-bone.)
2. The second bone of the sternum. 3, The cartilage of the sternum. 4,
The first dorsal vertebra, (a bone of the spinal column.) 5, The last
dorsal vertebra. 6, The first rib. 7, Its head. 8, Its neck. 9, Its
tubercle. 10, The seventh, or last true rib. 11, The cartilage of the
third rib. 12, The floating ribs.]
84. The STERNUM is composed of eight pieces in the child. These unite
and form but three parts in the adult. In youth, the two upper
portions are converted into bone, while the lower portion remains
cartilaginous and flexible until extreme old age, when it is often
converted into bone.
85. The RIBS are connected with the spinal column, and increase in
length as far as the seventh. From this they successively become
shorter. The direction of the ribs from above, downward, is oblique,
and their curve diminishes from the first to the twelfth. The external
surface of each rib is convex; the internal, concave. The inferior, or
lower ribs, are, however, very flat.
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83. Describe the thorax. Explain fig. 9. 84. Describe the sternum. 85.
Describe the ribs.
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86. The seven upper ribs are united to the sternum, through the medium
of cartilages, and are called the _true ribs_. The cartilages of the
next three are united with each other, and are not attached to the
sternum; these are called _false ribs_. The lowest two are called
_floating ribs_, as they are not connected either with the sternum or
the other ribs.
87. The SPINAL COLUMN is composed of twenty-four pieces of bone. Each
piece is called a _vert'e-bra_. On examining one of the bones, we find
seven projections, called _processes_; four of these, that are
employed in binding the bones together, are called _articulating_
processes; two of the remaining are called the _transverse_; and the
other, the _spinous_. The last three give attachment to the muscles of
the back.
88. The large part of the vertebra, called the body, is round and
spongy in its texture, like the extremity of the round bones. The
processes are of a more dense character. The projections are so
arranged that a tube, or canal, is formed immediately behind the
bodies of the vertebrae, in which is placed the _me-dul'la spi-na'lis_,
(spinal cord,) sometimes called the pith of the back-bone.
89. Between these joints, or vertebrae, is a peculiar and highly
elastic substance, which much facilitates the bending movements of the
back. This compressible cushion of cartilage also serves the important
purpose of diffusing and diminishing the shock in walking, running, or
leaping, and tends to protect the delicate texture of the brain.
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86. How are the ribs united to the sternum? 87. Describe the spinal
column. 88. Give the structure of the vertebra. Where is the spinal
cord placed? 89. What is placed between each vertebra? What is its
use?
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90. Another provision for the protection of the brain, which bears
convincing proof of the wisdom and beneficence of the Creator, is the
antero-posterior, or forward and backward curve of the spinal column.
Were it a straight column, standing perpendicularly, the slightest
jar, in walking, would cause it to recoil with a sudden jerk; because,
the weight bearing equally, the spine would neither yield to the one
side nor the other. But, shaped as it is, we find it yielding in the
direction of the curves, and thus the force of the shock is diffused.
[Illustration: Fig. 10. A vertebra of the neck. 1, The body of the
vertebra. 2, The spinal canal. 4, The spinous process, cleft at its
extremity. 5, The transverse process. 7, The inferior articulating
process. 8, The superior articulating process.]
[Illustration: Fig. 11. 1, The cartilaginous substance that connects the
bodies of the vertebrae. 2, The body of the vertebra. 3, The spinous
process. 4, 4, The transverse processes. 5, 5, The articulating
processes. 6, 6, A portion of the bony bridge that assists in forming the
spinal canal, (7.)]
_Observation._ A good idea of the structure of the vertebrae may be
obtained by examining the spinal column of a domestic animal, as the
dog, cat, or pig.
91. The PELVIS is composed of four bones; the two _in-nom-i-na'ta_,
(nameless bones,) the _sa'crum_, and the _coc'cyx_.
92. The INNOMINATUM, in the child, consists of three pieces. These,
in the adult, become united, and constitute but one bone. In the sides
of these bones is a deep socket, or depression, like a cup, called the
_ac-e-tab'u-lum_, in which the round head of the thigh-bone is
placed.
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90. What is said of the curves of the spinal column? What is
represented by fig. 10? By fig. 11? How can the structure of the
vertebrae be seen? 91. Of how many bones is the pelvis composed? 92.
What is said of the innominatum in the child?
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93. The SACRUM, so called because the ancients offered it in
sacrifices, is a wedge-shaped bone, that is placed between the
innominata, and to which it is bound by ligaments. Upon its upper
surface it connects with the lower vertebra. At its inferior, or lower
angle, it is united to the coccyx. It is concave upon its anterior,
and convex upon its posterior surface.
[Illustration: Fig. 12. 1, 1, The innominata, (nameless bones.) 2, The
sacrum. 3, The coccyx. 4, 4, The acetabulum. a, a, The pubic portion of
the innominata. d, The arch of the pubes; e, The junction of the sacrum
and lower lumbar vertebra.]
94. The COCCYX, in infants, consists of several pieces, which, in
youth, become united and form one bone. This is the terminal extremity
of the spinal column.
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In the adult? Describe the acetabulum. 93. Describe the sacrum.
Explain fig. 12. 94. Describe the coccyx.
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CHAPTER V.
ANATOMY OF THE BONES, CONTINUED
95. The bones of the upper and lower limbs are enlarged at each
extremity, and have projections, or processes. To these, the tendons
of muscles and ligaments are attached, which connect one bone with
another. The shaft of these bones is cylindrical and hollow, and in
structure, their exterior surface is hard and compact, while the
interior portion is of a reticulated character. The enlarged
extremities of the round bones are more porous than the main shaft.
96. The UPPER EXTREMITIES contain sixty-four bones--the _Scap'u-la_,
(shoulder-blade;) the _Clav'i-cle_, (collar-bone;) the _Hu'mer-us_,
(first bone of the arm;) the _Ul'na_ and _Ra'di-us_, (bones of the
fore-arm;) the _Car'pus_, (wrist;) the _Met-a-car'pus_, (palm of the
hand;) and the _Pha-lan'ges_, (fingers and thumb.)
97. The CLAVICLE is attached, at one extremity, to the sternum; at the
other, it is united to the scapula. It is shaped like the Italic
_[s]_. Its use is to keep the arms from sliding toward the breast.
98. The SCAPULA is situated upon the upper and back part of the chest.
It is flat, thin, and of a triangular form. This bone lies upon and is
retained in its position by muscles. By their contractions it may be
moved in different directions.
99. The HUMERUS is cylindrical, and is joined at the elbow with the
ulna of the fore-arm; at the scapular extremity, it is lodged in the
_glenoid_ cavity, where it is surrounded by a membranous bag, called
the _capsular ligament_.
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95-104. _Give the anatomy of the bones of the upper extremities._ 95.
Give the structure of the bones of the extremities. 96. How many bones
in the upper extremities? Name them. 97. Give the attachments of the
clavicle. What is its use? 98. Describe the scapula. How is it
retained in its position? 99. Describe the humerus.
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[Illustration: Fig. 13. 1, The shaft of the humerus. 2, The large, round
head that is placed in the glenoid cavity. 3, 4, Processes, to which
muscles are attached. 5, A process, called the external elbow. 6, A
process, called the internal elbow. 7, The articulating surface upon
which the ulna rolls.]
[Illustration: Fig. 14. 1, The body of the ulna. 2, The shaft of the
radius. 3, The upper articulation of the radius and ulna. 4, Articulating
cavity, in which the lower extremity of the humerus is placed. 5, Upper
extremity of the ulna, called the olecranon process, which forms the
point of the elbow. 6, Space between the radius and ulna, filled by the
intervening ligament. 7, Styloid process of the ulna. 8, Surface of the
radius and the ulna, where they articulate with the bones of the wrist.
9, Styloid process of the radius.]
100. The ULNA articulates with the humerus at the elbow, and forms a
perfect hinge-joint. This bone is situated on the inner side of the
fore-arm.
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What is represented by fig. 13? By fig. 14? 100. Describe the ulna.
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101. The RADIUS articulates with the bones of the carpus and forms the
wrist-joint. This bone is situated on the outside of the fore-arm,
(the side on which the thumb is placed.) The ulna and radius, at their
extremities, articulate with each other, by which union the hand is
made to rotate, permitting its complicated and varied movements.
102. The CARPUS is composed of eight bones, ranged in two rows, and so
firmly bound together, as to permit only a small amount of movement.
[Illustration: Fig. 15. U, The ulna. R, The radius. S, The scaphoid bone.
L, The semilunar bone. C, The cuneiform bone. P, The pisiform bone. These
four form the first row of carpal bones. T, T, The trapezium and
trapezoid bones. M, The os magnum. U, The unciform bone. These four form
the second row of carpal bones. 1, 1, 1, 1, 1, The metacarpal bones of
the thumb and fingers.]
[Illustration: Fig. 16. 10, 10, 10, The metacarpal bones of the hand. 11,
11, First range of finger-bones. 12, 12, Second range of finger-bones.
13, 13, Third range of finger-bones. 14, 15, Bones of the thumb.]
103. The METACARPUS is composed of five bones, upon four of which the
first range of the finger-bones is placed; and upon the other, the
first bone of the thumb. The five metacarpal bones articulate with the
second range of carpal bones.
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101. The radius. 102. How many bones in the carpus? How are they
ranged? 103. Describe the metacarpus.
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104. The PHALANGES of the fingers have three ranges of bones, while
the thumb has but two.
_Observation._ The wonderful adaptation of the hand to all the
mechanical offices of life, is one cause of man's superiority over the
rest of creation. This arises from the size and strength of the
thumbs, and the different lengths of the fingers.
105. The LOWER EXTREMITIES contain sixty bones--the _Fe'mur_,
(thigh-bone;) the _Pa-tel'la_, (knee-pan;) the _Tib'i-a_, (shin-bone;)
the _Fib'u-la_, (small bone of the leg;) the _Tar'sus_, (instep;) the
_Met-a-tar'sus_, (middle of the foot;) and the _Pha-lan'ges_, (toes.)
106. The FEMUR is the longest bone in the system. It supports the
weight of the head, trunk, and upper extremities. The large, round
head of this bone is placed in the acetabulum. This articulation is a
perfect specimen of the ball and socket joint.
107. The PATELLA is a small bone connected with the tibia by a strong
ligament. The tendon of the _ex-tens'or_ muscles of the leg is
attached to its upper edge. This bone is placed on the anterior part
of the lower extremity of the femur, and acts like a pulley, in the
extension of the limb.
108. The TIBIA is the largest bone of the leg. It is of a triangular
shape, and enlarged at each extremity.
109. The FIBULA is a smaller bone than the tibia, but of similar
shape. It is firmly bound to the tibia, at each extremity.
110. The TARSUS is formed of seven irregular bones, which are so
firmly bound together as to permit but little movement.
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104. How many ranges of bones have the phalanges? 105-112. _Give the
anatomy of the bones of the lower extremities._ 105. How many bones in
the lower extremities? Name them. 106. Describe the femur. 107.
Describe the patella. What is its function? 108. What is the largest
bone of the leg called? What is its form? 109. What is said of the
fibula? 110. Describe the tarsus.
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[Illustration: Fig. 17. 1, The shaft of the femur, (thigh-bone.) 2, A
projection, called the trochantar minor, to which are attached some
strong muscles. 4, The trochantar major, to which the large muscles of
the hip are attached. 3, The head of the femur. 5, The external
projection of the femur, called the external condyle. 6, The internal
projection, called the internal condyle. 7, The surface of the lower
extremity of the femur, that articulates with the tibia, and upon which
the patella slides.]
[Illustration: Fig. 18. 1, The tibia. 5, The fibula. 8, The space between
the two, filled with the inter-osseous ligament. 6, The junction of the
tibia and fibula at their upper extremity. 2, The external malleolar
process, called the external ankle. 3, The internal malleolar process,
called the internal ankle. 4, The surface of the lower extremity of the
tibia, that unites with one of the tarsal bones to form the ankle-joint.
7, The upper extremity of the tibia, upon which the lower extremity of
the femur rests.]
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Explain fig. 17. Explain fig. 18.
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111. The METATARSAL bones are five in number. They articulate at one
extremity with one range of tarsal bones; at the other extremity, with
the first range of the toe-bones.
[Illustration: Fig. 19. A representation of the upper surface of the
bones of the foot. 1, The surface of the astragulus, where it unites with
the tibia. 2, The body of the astragulus. 3, The calcis, (heel-bone.) 4,
The scaphoid bone. 5, 6, 7, The cuneiform bones. 8, The cuboid. 9, 9, 9,
The metatarsal bones. 10, The first bone of the great toe. 11, The second
bone. 12, 13, 14, Three ranges of bones, forming the small toes]
[Illustration: Fig. 20. A side view of the bones of the foot, showing its
arched form. The arch rests upon the _heel_ behind, and the _ball_ of the
toes in front. 1, The lower part of the tibia. 2, 3, 4, 5, Bones of the
tarsus. 6, The metatarsal bone. 7, 8, The bones of the great toe. These
bones are so united as to secure a great degree of elasticity, or spring.]
_Observation._ The tarsal and metatarsal bones are united so as to
give the foot an arched form, convex above, and concave below. This
structure conduces to the elasticity of the step, and the weight of
the body is transmitted to the ground by the spring of the arch, in a
manner which prevents injury to the numerous organs.
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111. Describe the metatarsal bones. Explain fig. 19. What is
represented by fig. 20? What is said of the arrangement of the bones
of the foot?
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112. The PHALANGES (fig. 19) are composed of fourteen bones; each of
the small toes has three ranges of bones, while the great toe has but
two.
113. The JOINTS form an interesting part of the body. In their
construction, every thing shows the regard that has been paid to the
security and the facility of motion of the parts thus connected
together. They are composed of the extremities of two or more
bones, _Car'ti-lages_, (gristles,) _Syn-o'vi-al_ membrane, and
_Lig'a-ments_.
[Illustration: Fig. 21 The relative position of the bones, cartilages,
and synovial membrane. 1, 1, The extremities of two bones that concur to
form a joint. 2, 2, The cartilages that cover the end of the bones. 3, 3,
3, 3, The synovial membrane which covers the cartilage of both bones, and
is then doubled back from one to the other; it is represented by the
dotted lines.]
[Illustration: Fig. 22. A vertical section of the knee-joint. 1, The
femur. 3, The patella. 5, The tibia. 2, 4, The ligaments of the patella.
6, The cartilage of the tibia 12, The cartilage of the femur. * * * *,
The synovial membrane.]
114. CARTILAGE is a smooth, solid, elastic substance, of a pearly
whiteness, softer than bone. It forms upon the articular surfaces of
the bones a thin incrustation, not more than the sixteenth of an inch
in thickness. Upon convex surfaces it is the thickest in the centre,
and thin toward the circumference; while upon concave surfaces, an
opposite arrangement is presented.
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112. Describe the phalanges. 113-118. _Give the anatomy of the
joints._ 113. What is said of the joints? Of what are the joints
composed? What is illustrated by fig. 21? By fig. 22? 114. Define
cartilage.
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115. The SYNOVIAL MEMBRANE is a thin, membranous layer, which covers
the cartilages, and is thence bent back, or reflected upon the inner
surfaces of the ligaments which surround and enter into the
composition of the joints. This membrane forms a closed sac, like the
membrane that lines an egg-shell.
[Illustration: Fig. 23. The anterior ligaments of the knee-joint. 1, The
tendon of the muscle that extends the leg. 2, The patella. 3, The
anterior ligament of the patella, near its insertion. 4, 4, The synovial
membrane. 5, The internal lateral ligament. 6, The long external lateral
ligament. 7, The anterior and superior ligament that unites the fibula to
the tibia.]
[Illustration: Fig. 24. 2, 3, The ligaments that extend from the clavicle
(1) to the scapula (4.) The ligaments 5, 6, extend from the scapula to
the first bone of the arm.]
116. Beside the synovial membrane, there are numerous smaller sacs,
called _bur'sae mu-co'sae_. These are often associated with the
articulation. In structure, they are analogous to synovial membranes,
and secrete a similar fluid.
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115. Describe the synovial membrane. 116. Describe the bursae mucosae.
What is represented by fig. 23? By fig. 24?
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117. The LIGAMENTS are composed of numerous straight fibres, collected
together, and arranged into short bands of various breadths, or so
interwoven as to form a broad layer, which completely surrounds the
articular extremities of the bones, and constitutes a capsular
ligament. These connecting bands are white, glistening, and inelastic.
Most of the ligaments are found exterior to the synovial membrane.
118. The bones, cartilages, ligaments, and synovial membrane are
insensible when in health; yet they are supplied with organic nerves,
as well as with arteries, veins, and lymphatics.
_Observation._ The joints of the domestic animals are similar in their
construction to those of man. To illustrate this part of the body, a
fresh joint of the calf or sheep may be used. After divesting the
joints of the skin, the satin-like bands, or ligaments, will be seen
passing from one bone to the other, under which may be observed the
membranous bag, called the capsular ligament. This is very smooth, as
it is lined with the soft synovial membrane, beneath which will be
seen the cartilage, that may be cut with a knife, and under this the
rough extremity of the ends of the bones.
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117. Of what are ligaments composed? What is the appearance of these
bands? Where are they found? 118. With what vessels are the cartilages
and ligaments supplied? How can the structure of the joints be
explained?
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CHAPTER VI.
PHYSIOLOGY OF THE BONES.
119. The bones are the framework of the system. By their solidity and
form, they not only retain every part of the fabric in its proper
shape, but afford a firm surface for the attachment of the muscles and
ligaments. By means of the bones, the human frame presents to the eye
a wonderful piece of mechanism, uniting the most finished symmetry of
form with freedom of motion, and also giving security to many
important organs.
120. To give a clear idea of the relative uses of the bones and
muscles, we will quote the comparison of another, though, as in other
comparisons, there are points of difference. The "bones are to the
body what the masts and spars are to the ship,--they give support and
the power of resistance. The muscles are to the bones what the ropes
are to the masts and spars. The bones are the levers of the system; by
the action of the muscles their relative positions are changed. As the
masts and spars of a vessel must be sufficiently firm to sustain the
action of the ropes, so the bones must possess the same quality to
sustain the action of the muscles in the human body."
121. Some of the bones are designed exclusively for the protection of
the organs which they enclose. Of this number are those that form the
skull, the sockets of the eye, and the cavity of the nose. Others, in
addition to the protection they give to important organs, are useful
in movements of certain kinds. Of this class are the bones of the
spinal column, and ribs. Others are subservient to motion. Of this
class are the upper and lower extremities.
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119-128. _Give the physiology of the bones._ 119. How may the bones be
considered? 120. To what may the bones be compared? 121. Give the
different offices of the bones.
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122. The bones are subject to growth and decay; to removal of old,
useless matter, and the deposit of new particles, as in other tissues.
This has been tested by the following experiment. Some of the inferior
animals were fed with food that contained madder. In a few days, some
of the animals were killed, and their bones exhibited an unusually
reddish appearance. The remainder of the animals were, for a few
weeks, fed on food that contained no coloring principle. When they
were killed, their bones exhibited the usual color of such animals.
The coloring matter, which had been deposited, had been removed by the
action of the lymphatics.
123. The extremities of the bones that concur in forming a joint,
correspond by having their respective configurations reciprocal. They
are, in general, the one convex, and the other concave. In texture
they are porous, and consequently more elastic than if more compact.
These are covered with a cushion of cartilage. The elastic character
of these parts acts as so many springs, in diminishing the jar which
important organs of the system would otherwise receive.
124. The synovial membrane secretes a viscous fluid, which is called
_syn-o'vi-a_. This lubricating fluid of the joints enables the
surfaces of the bones and tendons to move smoothly upon each other,
thus diminishing the friction consequent on their action.
_Observations._ 1st. In this secretion is manifested the skill and
omnipotence of the Great Architect; for no machine of human invention
supplies to itself, by its own operations, the necessary lubricating
fluid. But, in the animal frame, it is supplied in proper quantities,
and applied in the proper place, and at the proper time.
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122. What is said of the change in bones? How was it proved that there
was a constant change in the osseous fabric? 123. What is said of the
extremities of the bones that form a joint? 124. What is synovia? Its
use? What is said of this lubricating fluid?
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2d. In some cases of injury and disease, the synovial fluid is
secreted in large quantities, and distends the sac of the joint. This
affection is called dropsy of the joint, and occurs most frequently in
that of the knee.
125. The function of the ligaments is to connect and bind together the
bones of the system. By them the small bones of the wrist and foot, as
well as the large bones, are as securely fastened as if retained by
clasps of steel. Some of them are situated within the joints, like a
central cord, or pivot, (3, fig. 26.) Some surround it like a hood,
and contain the lubricating synovial fluid, (8, 9, fig. 25,) and some
in the form of bands at the side, (5, 6, fig. 23.)
[Illustration: Fig. 25. 8, 9, The ligaments that extend from the hip-bone
(6) to the femur, (5.)]
[Illustration: Fig. 26. 2, The socket of the hip-joint. 5, The head of
the femur, which is lodged in the socket. 3, The ligament within the
socket.]
126. By the ligaments the lower jaw is bound to the temporal bones,
and the head to the neck. They extend the whole length of the spinal
column, in powerful bands, on the outer surface, between the spinal
bones, and from one spinous process to another. They bind the ribs to
the vertebrae, to the transverse process behind, and to the sternum in
front; and this to the clavicle; and this to the first rib and
scapula; and this last to the humerus.
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What is the effect when the synovial fluid is secreted in large
quantities? 125. What is the function of the ligaments? 126. Mention
how the bones of the system are connected.
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127. They also bind the two bones of the fore-arm at the elbow-joint;
and these to the wrist; and these to each other and to those of the
hand; and these last to each other and to those of the fingers and
thumb. In the same manner, they bind the bones of the pelvis together;
and these to the femur; and this to the two bones of the leg and
patella; and so on, to the ankle, foot, and toes, as in the upper
extremities.
[Illustration: Fig. 27. 1, A front view of the lateral ligaments of the
finger-joints. 2, A view of the anterior ligaments (_a_, _b_,) of the
finger-joints. 3, A side view of the lateral ligaments of the finger
joints.]
128. The different joints vary in range of movement, and in complexity
of structure. Some permit motions in all directions, as the shoulder;
some move in two directions, permitting only flexion and extension of
the part, as the elbow; while others have no movement, as the bones of
the head in the adult.
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Explain fig. 27. 128. Describe the variety of movements in the
different joints.
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[Illustration: Fig. 28. 1, 1, The spinal column. 2, The skull. 3, The
lower jaw. 4, The sternum. 5, The ribs. 6, 6, The cartilages of the ribs.
7, The clavicle. 8, The humerus. 9, The shoulder-joint. 10, The radius.
11, The ulna. 12, The elbow joint. 13, The wrist. 14, The hand. 15, The
haunch-bone. 16, The sacrum. 17, The hip-joint. 18, The thigh-bone. 19,
The patella. 20, The knee-joint. 21, The fibula. 22, The tibia. 23, The
ankle-joint. 24, The foot. 25, 26, The ligaments of the clavicle,
sternum, and ribs. 27, 28, 29, The ligaments of the shoulder, elbow, and
wrist. 30, The large artery of the arm. 31, The ligaments of the
hip-joint. 32, The large blood-vessels of the thigh. 33, The artery of
the leg. 34, 35, 36, The ligaments of the patella, knee, and ankle.]
_Note._ Let the pupil, in form of topics, review the anatomy and
physiology of the bones from fig. 28, or from anatomical outline
plates No. 1 and 2.
CHAPTER VII
HYGIENE OF THE BONES.
129. _The bones increase in size and strength by use, while they are
weakened by inaction._ Exercise favors the deposition of both animal
and earthy matter, by increasing the circulation and nutrition in this
texture. For this reason, the bones of the laborer are dense and
strong, while those who neglect exercise, or are unaccustomed to
manual employment, are deficient in size, and have not a due
proportion of earthy matter to give them the solidity and strength of
the laboring man.
_Observation._ The tendons of the muscles are attached near the
extremities of the bones. Exercise of the muscles increases the action
of the vessels of that part to which the tendons are attached, and
thus increases the nutrition and size of this portion of the bone.
Hence the joints of an industrious mechanic or farmer are larger than
those of an individual who has not pursued manual vocations.
130. _The gelatinous bones of the child are not so well adapted for
labor and severe exercise as those of an adult._ 1st. They are liable
to become distorted. 2d. They are consolidated by the deposition of
earthy material before they are fully and properly developed. If a
young animal, as the colt, be put to severe, continued labor, the
deposition of earthy matter is hastened, and the bones are
consolidated before they attain full growth. Such colts make small and
inferior animals. Similar results follow, if a youth is compelled to
toil unduly before maturity of growth is attained. On the other hand,
moderate and regular labor favors a healthy development and
consolidation of the bones.
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129-148. _Give the hygiene of the bones._ 129. What effect has
exercise upon the bones? What effect has inaction? Why are the joints
of the industrious farmer and mechanic larger than those of a person
unaccustomed to manual employment? 130. Give the first reason why the
bones of the child are not adapted to severe exercise. The second
reason.
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131. _The kind and amount of labor should be adapted to the age,
health, and development of the bones._ Neither the flexible bones of
the child nor the brittle bones of the aged man are adapted, by their
organization, to long-continued, and hard labor. Those of the one bend
too easily, while those of the other fracture too readily. In middle
age, the proportions of animal and earthy matter are, usually, such as
to give the proper degree of flexibility, firmness, and strength for
labor, with little liability to injury.
132. _The imperfectly developed bones of the young child will not bear
long-continued exertions or positions without injury._ Hence the
requisitions of the rigid disciplinarian of schools, are unwise when
he compels his pupils to remain in one position for a long time. He
may have a "quiet school;" but, not unfrequently, by such discipline,
the constitution is impaired, and permanent injury is done to the
pupils.
133. _The lower extremities, in early life, contain but a small
proportion of earthy matter_; they bend when the weight of the body is
thrown upon them for a long time. Hence, the assiduous attempts to
induce children to stand or walk, either naturally or artificially,
when very young, are ill advised, and often productive of serious and
permanent evil. The "bandy" or bow legs are thus produced.
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What effect has moderate, regular labor upon the growing youth? 131.
What remark respecting the kind and amount of labor? At what age are
the bones best fitted for labor? 132. What effect has long-continued
exertions or positions on the bones of a child? What is said of the
requisitions of some teachers, who have the famed "quiet schools"?
133. Why should not the child be induced to stand or walk, either
naturally or artificially, at too early an age?
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134. _The benches or chairs for children in a school-room should be of
such a height as to permit the feet to rest on the floor._ If the
bench is so high as not to permit the feet to rest upon the floor, the
weight of the limbs below the knee may cause the flexible bone of the
thigh to become curved. The child thus seated, is inclined to lean
forward, contracting an injurious and ungraceful habit. Again, when
the feet are not supported, the child soon becomes exhausted,
restless, and unfit for study. In the construction of a school-room,
the benches should be of different heights, so as to be adapted to the
different pupils, and they should also have appropriate backs.
[Illustration: Fig. 29. The position assumed when the seat is of proper
height, and the feet supported.]
[Illustration: Fig. 30. The position a child naturally assumes when the
seat is so high that the feet are not supported.]
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134. What is said of the benches or chairs in a school-room? What is
represented by fig. 29? By fig. 30? What is the effect when the lower
limbs are not supported?
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135. _Compression of the chest should be avoided._ In children, and
also in adults, the ribs are very flexible, and a small amount of
pressure will increase their curvature, particularly at the lower part
of the chest, and thus lessen the size of this cavity. The lower ribs
are united to the breast-bone, by long, yielding cartilages, and
compression may not only contract the chest, but an unseemly and
painful ridge may be produced, by the bending of the cartilages, on
one or both sides of the sternum.
[Illustration: Fig. 31. A natural and well-proportioned chest.]
[Illustration: Fig. 32. A chest fashionably deformed.]
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135. Why should compression of the chest be avoided? What is
represented by fig. 31? By fig. 32?
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136. Again, the cartilages on one side may be bent outward, while
those on the opposite side are bent inward, thus forming a depression
parallel with the sternum. In some instances, the anterior extremity
of the lower ribs on each side are brought nearly or quite together.
In these instances, the movable extremities of the ribs are drawn down
toward the haunch-bones, while the space between the ribs is lessened.
All this may be effected by tight or "snug" clothing. Therefore the
apparel of a child should be loose, and supported over the shoulders,
to avoid the before-mentioned evils. The same may be said of the
clothing for adults.
137. _The erect position in sitting and standing should be assiduously
observed._ The spinal column, in its natural position, curves from
front to back, but not from side to side The admirable arrangement of
the bones, alternating with cartilages, permits a great variety of
motions and positions; and when the spine is inclined to either side,
the elasticity of its cartilages tends to restore it to its natural
position. For this reason we may incline the spinal column in any
direction for a short time, without danger of permanent curvature, if,
afterward, the erect position is assumed.[4]
[4] Compare 1, 1, Fig. 28, with 2, 2, 2, Fig. 48.
138. But if a stooping position, or a lateral curved posture, is
continued for a long time, the spinal column does not easily recover
its proper position, for the compressed edges of the cartilages lose
their power of reaction, and finally one side of the cartilage becomes
thinned, while the other is thickened; and these wedge-shaped
cartilages produce a permanent curvature of the spinal column. In a
similar way, the student, seamstress, artisan, and mechanic acquire a
stooping position, and become round shouldered, by inclining forward
to bring their books or work nearer the eyes.
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136. May simply "snug" clothing compress the cartilages? How should
the apparel of a child be worn? 137. In what direction does the spinal
column, in its natural position, curve? What restores it to its
natural position when curved laterally? 138. What is the effect if a
lateral curved position of the spinal column is continued for a long
time? 139. When one shoulder is elevated for a long time, what is the
effect upon the spinal column?
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139. Pupils, while writing, drawing, and sometimes while studying,
frequently incline the spinal column to one side, in order to
accommodate themselves to the desks at which they are seated. Often,
these are higher than the elbow as it hangs from the shoulder while at
rest. This attitude elevates one shoulder while it depresses the
other; consequently, the upper part of the spinal column is inclined
toward the elevated shoulder, and the lower part is curved in the
opposite direction, giving the form of the letter _S_ to the
supporting column of the body.
[Illustration: Fig. 33. The table is of proper height, the position is
correct, and the spinal column, 1, 1, is straight, while the shoulders
are of equal height.]
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What does fig. 33 represent?
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_Experiment._ Let a pupil be placed at a desk or table with one elbow
raised, as is frequently seen while writing, or at study, and observe
the condition of the shoulder and spinal column in this position.
Place another pupil at a table no higher than the elbow when it hangs
by the side while sitting, and observe the appearance of the shoulders
and spinal column. By a comparison of the two attitudes, the preceding
remarks will be comprehended and appreciated.
[Illustration: Fig. 34. The table is too high, and the position is
oblique and improper. The right shoulder is seen higher than the left,
while the spinal column, 1, 1, exhibits three curves.]
140. One shoulder may be elevated, and no injurious results follow,
provided care is taken not to keep it in the raised position too long,
or if the opposite shoulder is elevated for the same period of time.
The right shoulder projects more frequently than the left. This arises
from the greater use of the right hand with the shoulder elevated, and
not unfrequently the oblique positions assumed in performing the daily
vocations of life. With proper care, and by calling into action the
left shoulder, this deformity can be prevented.
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What experiment is mentioned? What does fig. 34 represent? 140. How
can one shoulder be elevated and no injurious results follow?
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[Illustration: Fig. 35. A representation of a deformed trunk.]
141. The loss of symmetry and diminution of height from deformed
spines are minor considerations, compared with the distortions that
the chest experiences, thereby impairing respiration and inducing
diseases of the heart and lungs. The invasion of the functions of
these two important organs lessens the vitality of the whole system,
and causes general ill health. Again, the curvature of the spinal
column is frequently attended by irritation and disease of the spinal
cord.
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Why does the right shoulder project more frequently than the left? How
can this deformity be prevented? 141. What is said of deformed spinal
columns?
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142. Eminent physicians, both in this country and France state that
not more than one female in ten, who has been fashionably educated, is
free from deformities of the shoulder or spinal column. Teachers, as
well as mothers, should notice the positions of the child in
performing the tasks allotted to it, whether studying or pursuing any
employment. The feebler the organization of the child, the more
frequently should there be a change of position.
143. When a slight projection of the shoulder, with a curvature of the
spine, exists, it can be improved by walking with a book, or something
heavier, upon the head; to balance which, the spinal column must be
nearly erect. Those people that carry burdens upon their heads seldom
have crooked spines.
_Observation._ Persons from the North, in travelling through the
Southern States, are surprised to see the heavy burdens that the
porters carry on their heads. It is not unusual to see them walking at
a rapid pace, with one or two trunks, weighing fifty or eighty pounds
each, upon their heads. Occasionally, we meet an itinerant toy-man,
with his tray of fragile merchandise upon his head, walking with as
much apparent security, as though his toys, or images, were in his
hands. This is the easiest method of carrying burdens, because the
position of the head and spinal column is erect.
144. _If the animal and earthy matter of the bones is not deposited in
proper proportions, they are deficient in strength._ If the gelatin
predominates, the bones are weak, and become distorted. When
nutrition is defective in the cylindrical bones, the heads are
generally enlarged, and the shafts crooked; if in the spinal column,
it may be curved; or in the cranium, it may be enlarged. This disease
is familiarly known by the name of rickets. It is most common among
these who have poor and insufficient food, live in dark, damp rooms,
and breathe a vitiated air. The prevention and remedies for this
disease are cleanliness, regular exercise, pure air, and nutritious
food.
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142. What statement by eminent physicians respecting deformities of
the spine? What caution to teachers and mothers? 143. Why should we
stand and sit erect? How may slight deformities of the spine be
prevented? What is frequently noticed in travelling South? 144. What
is the effect upon the bones when the gelatin preponderates?
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145. When a bone is broken, some days elapse before the substance that
reunites it is thrown out from the blood. In young persons, it may be
secreted during the second or third week, and in individuals advanced
in life, usually during the third and fourth week. When the bone is
uniting, during the second, third, or fourth week, the attention of a
surgeon is more needed than during the first week. At this time, the
ends of the bone should be placed together with accuracy, which
requires the careful application of proper dressing. After the bones
have united, it will take some weeks to consolidate the uniting
material and render the "callus," or union, firm. During this time,
the limb should be used with care.
_Observation._ When a bone is fractured, a surgeon is immediately
called, and the bone is "set." While the limb remains swelled and
painful, the surgeon is required to attend and keep the dressings
(bandages and splints) on. When the swelling has abated, and the pain
subsided, frequently the patient intimates to the surgeon that his
services can be dispensed with, as the "limb is doing well." This is
the most important period, as the bone is uniting, and, unless the
ends are nicely adjusted, the dressing properly applied, the person
will find, on recovery, a shortened and crooked limb. The surgeon is
then censured, when he is not blamable.
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What is one cause of rickets? What are the prevention and remedies for
this disease? 145. Does the time vary when the reuniting substance of
the bone is secreted from the blood? When is the surgeon's care most
needed? Why?
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146. It is seldom that a bone is displaced without injury to the
connecting ligaments and membranes. When these connecting bands are
lacerated, pain, swelling, and other symptoms indicating inflammation
succeed, which should be removed by proper treatment, directed by a
surgical adviser.
147. In sprains, but few, if any, of the fibres of the connecting
ligaments are lacerated; but they are unduly strained and twisted,
which occasions acute pain at the time of the injury. This is followed
by inflammation and weakness of the joints. The treatment of these
injuries is similar to that of a dislocated bone after its reduction.
The most important item in the treatment during the few first days, is
rest.
148. In persons of scrofulous constitutions, and those in whom the
system is enfeebled by disease, white swellings and other chronic
diseases of the joints frequently succeed sprains. Such persons cannot
be too assiduous in adopting a proper and early treatment of injured
joints.
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146. What parts are injured in the displacement of a bone? 147. What
causes the acute pain in sprains? What is a good remedy for this kind
of injury? 148. What caution to persons of scrofulous constitutions?
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CHAPTER VIII
THE MUSCLES.
149. All the great motions of the body are caused by the movement of
some of the bones which form the framework of the system; but these,
independently of themselves, have not the power of motion, and only
change their position through the action of other organs attached to
them, which, by contracting, draw the bones after them. In some of the
slight movements, as the winking of the eye, no bones are displaced.
These moving, contracting organs are the _Mus'cles_, (lean meat.)
ANATOMY OF THE MUSCLES.
150. The MUSCLES, by their size and number, constitute the great bulk
of the body, upon which they bestow form and symmetry. In the limbs,
they are situated around the bones, which they invest and defend,
while they form, to some of the joints, their principal protection. In
the trunk, they are spread out to enclose cavities, and constitute a
defensive wall, capable of yielding to internal pressure, and
reassuming its original state.
151. In structure, a muscle is composed of _fas-cic'u-li_ (bundles of
fibres) of variable size. These are enclosed in a cellular membranous
investment, or sheath. Every bundle composed of a number of small
fibres, and each fibre consists of a number of filaments, each of
which is enclosed in a delicate sheath. Toward the extremity of the
organ the muscular fibre ceases, and the cellular structure becomes
aggregated, and so modified as to constitute _ten'dons_, (cords,) by
which the muscle is tied to the surface of the bone. The union is so
firm, that, under extreme violence, the bone will sooner break than
permit the tendon to separate from its attachment. In some situations,
there is an expansion of the tendon, in the manner of a membrane,
called _Ap-o-neu-ro'sis_, or _Fas'ci-a_.
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149. How are all the motions of the body produced? What are these
motor organs called? 150-160. _Give the anatomy of the muscles._ 150.
What is said of the muscles? 151. Give their structure.
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_Observation._ The pupil can examine a piece of boiled beef, or the
leg of a fowl, and see the structure of the fibres and tendons of a
muscle.
[Illustration: Fig. 36. 1, A representation of the direction and
arrangement of the fibres in a fusiform, or spindle-shaped muscle. 2, In
a radiated muscle. 3, In a penniform muscle. 4, In a bipenniform muscle.
_t_, _t_, The tendons of a muscle.]
152. Muscles present various modifications in the arrangement of their
fibres, as relates to their tendinous structure. Sometimes they are
completely longitudinal, and terminate, at each extremity, in a
tendon, the entire muscle being spindle-shaped. In other situations,
they are disposed like the rays of a fan, converging to a tendinous
point, and constituting a _ra'di-ate_ muscle. Again they are
_pen'ni-form_, converging, like the plumes of a pen, to one side of a
tendon, which runs the whole length of the muscle; or they are
_bi-pen'ni-form_, converging to both sides of the tendon.
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How are tendons or cords formed? What is the expansion of a tendon
called? How can the structure of muscles and their fibres be shown?
What does fig. 36 represent? 152. Give the different arrangements of
muscular fibres.
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153. In the description of a muscle, its attachments are expressed by
the terms "origin" and "insertion." The term _origin_ is generally
applied to the more fixed or central attachment, or to the point
toward which motion is directed; while _insertion_ is assigned to the
more movable point, or to that most distant from the centre. The
middle, fleshy portion is called the "belly," or "swell." The color of
a muscle is red in warm-blooded fish and animals; and each fibre is
supplied with arteries, veins, lymphatics, and both sensitive and
motor nervous filaments.
154. The FASCIA is of various extent and thickness, distributed
through the different regions of the body, for the purpose of
investing and protecting the softer and more delicate organs. An
instance is seen in the membrane which envelopes a leg of beef, and
which is observed on the edges of the slices when it is cut for
broiling. When freshly exposed, it is brilliant in appearance, tough,
and inelastic. In the limbs it forms distinct sheaths to all the
muscles.
155. This tendinous membrane assists the muscles in their action, by
keeping up a tonic pressure on their surface. It aids materially in
the circulation of the fluids, in opposition to the laws of gravity.
In the palm of the hand and sole of the foot, it is a powerful
protection to the structures that enter into the formation of these
parts. In all parts of the system, the separate muscles are not only
invested by fascia, but they are arranged in layers, one over
another. The sheath of each muscle is loosely connected with another,
by the cellular membrane.
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153. What is meant by the origin of a muscle? The insertion? The
swell? What is the color of muscles? With what is each muscular fibre
supplied? 154. What is said of fascia? What is its appearance when
freshly exposed? 155. What effect has it on the muscles? Give other
uses of the fascia.
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156. The interstices between the different muscles are filled with
adipose matter, or fat. This is sometimes called the packing of the
system. To the presence of this tissue, youth are indebted for the
roundness and beauty of their limbs.
[Illustration: Fig. 37. A transverse section of the neck. The separate
muscles, as they are arranged in layers, with their investing fasciae, are
beautifully represented. As the system is symmetrical, figures are placed
only on one side. In the trunk the muscles are arranged in layers,
surrounded by fasciae, as in the neck. The same is true of the muscles of
the upper and lower limbs.
12, The trachea, (windpipe.) 13, The oesophagus, (gullet.) 14, The
carotid artery and jugular vein. 28, One of the bones of the spinal
column. The figures that are placed in the white spaces represent some of
the fasciae; the other figures indicate muscles.]
157. The muscles may be arranged, in conformity with the general
division of the body, into four parts: 1st. Those of the _Head_
and _Neck_. 2d. Those of the _Trunk_. 3d. Those of the _Upper
Extremities_. 4th. Those of the _Lower Extremities_.
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156. Give a reason why the limbs of youth are rounder than those of
the aged. Describe fig. 37.
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[Illustration: Fig. 38. The superficial layer of muscles on the face and
neck. 1, 1, The occipito-frontalis muscle. 2, The orbicularis
palpebrarum. 6, The levator labii superioris 7, The levator anguli oris.
8, The zygomaticus minor. 9, The zygomaticus major 10, The masseter. 11,
The depressor labii superioris. 13, The orbicularis oris. 15, The
depressor anguli oris. 16, The depressor labii inferioris. 18, The
sterno-hyoideus. 19, The platysma-myodes. 20, The superior belly of the
omo-hyoideus. 21, The sterno-cleido mastoideus. 20, The scalenus medius.
23, The inferior belly of the omo-hyoideus. 24, The trapezius.[5]
_Practical Explanation._ The muscle 1, 1, elevates the eyebrows. The
muscle 2 closes the eye. The muscle 6 elevates the upper lip. The muscles
7, 8, 9, elevate the angle of the mouth. The muscle 10 brings the teeth
together when eating. The muscle 11 depresses the upper lip. The muscle
13 closes the mouth. The muscle 15 depresses the angle of the mouth. The
muscle 16 draws down the lower lip. The muscles 18, 19, 20, 23, depress
the lower jaw and larynx and elevate the sternum. The muscle 21, when
both sides contract, draws the head forward, or elevates the sternum;
when only one contracts, the face is turned one side toward the opposite
shoulder. The muscles 18, 19, 20, 21, 22, 23, 24, aid in respiration.]
[5] In the plates illustrating the muscular system, the names of such
muscles are given as are referred to in the paragraph
"Practical Explanation." These names need not be committed to
memory. If a pupil wishes to acquire a knowledge of the general
attachment of the muscles represented in the plates, he can do
so by _comparing_ the muscular plate with that of the skeleton,
(fig. 28.)
_Observation._ When we are sick, and cannot take food, the body is
sustained by absorption of the fat. The removal of it into the blood
causes the sunken cheek, hollow eye, and prominent appearance of the
bones after a severe illness.
158. The number of muscles in the human body is more than five
hundred; in general, they form about the skeleton two layers, and are
distinguished into superficial and deep-seated muscles. Some of the
muscles are voluntary in their motions, or act under the government of
the will, as those which move the fingers, limbs, and trunk; while
others are involuntary, or act under the impression of their proper
stimulants, without the control of the individual, as the heart.
_Observations._ 1st. The abdominal muscles are expiratory, and the
chief agents for expelling the residuum from the rectum, the bile from
the gall bladder, the contents of the stomach and bowels when
vomiting, and the mucus and irritating substances from the bronchial
tubes, trachea, and nasal passages by coughing and sneezing. To
produce these effects they all act together. Their violent and
continued action sometimes produces hernia, and, when spasmodic, may
occasion ruptures of the different organs.
2d. The contraction and relaxation of the abdominal muscles and
diaphragm stimulate the stomach, liver, and intestines to a healthy
action, and are subservient to the digestive powers. If the
contractility of their muscular fibres is destroyed or impaired, the
tone of the digestive apparatus will be diminished, as in indigestion
and costiveness. This is frequently attended by a displacement of
those organs, as they generally gravitate towards the lower portion of
the abdominal cavity, when the sustaining muscles lose their tone and
become relaxed.
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What causes the hollow eye and sunken cheek after a severe sickness?
158. How many muscles in the human system? Into how many layers are
they arranged? What is a voluntary muscle? Give examples. What is an
involuntary muscle? Mention examples. Give observation 1st, respecting
the use of the abdominal muscles? Observation 2d.
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[Illustration: Fig. 39. A front view of the muscles of the trunk. On the
left side the superficial layer is seen; on the right, the deep layer. 1,
The pectoralis major muscle. 2, The deltoid muscle. 6, The pectoralis
minor muscle. 9, The coracoid process of the scapula. 11, The external
intercostal muscle. 12, The external oblique muscle 13, Its aponeurosis.
16, The rectus muscle of the right side. 18, The internal oblique muscle.
_Practical Explanation._ The muscle 1 draws the arm by the side, and
across the chest, and likewise draws the scapula forward. The muscle 2
elevates the arm. The muscle 6 elevates the ribs when the scapula is
fixed, or draws the scapula forward and downward when the ribs are fixed.
The muscles 12, 16, 18, bend the body forward or elevate the hips when
the muscles of both sides act. They likewise depress the rib in
expiration. When the muscles on only one side act, the body is twisted to
the same side.]
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Explain fig. 39. Give the function of some of the most prominent
muscles, from this figure.
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[Illustration: Fig. 40. A lateral view of the muscles of the trunk. 3,
The upper part of the external oblique muscle. 4, Two of the external
intercostal muscles. 5, Two of the internal intercostals. 6, The
transversalis muscle. 7, Its posterior aponeurosis. 8, Its anterior
aponeurosis. 11, The right rectus muscle. 13, The crest of the ilium, or
haunch-bone.
_Practical Explanation._ The rectus muscle, 11, bends the thorax upon the
abdomen when the lower extremity of the muscle is the fixed point; but
when the upper extremity is the fixed point, the effect is to bring
forward and raise the pelvis and lower extremities. They likewise depress
the ribs in respiration. The transverse muscle, 6, 7, 8, lessens the
cavity of the abdomen, and presses the intestines; stomach, and liver
upward, against the diaphragm, in expiration.]
3d. The region of the back, in consequence of its extent, is common to
the neck, the upper extremities, and the abdomen. The muscles of which
it is composed are numerous, and are arranged in six layers.
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What is represented by fig. 40? Give the function of some of the
muscles represented by this figure.
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[Illustration: Fig. 41 The first, second, and part of the third layer of
muscles of the back. The first layer is shown on the right, and the
second on the left side. 1, The trapezius muscle. 2, The spinous
processes of the vertebrae. 3, The acromion process and spine of the
scapula. 4, The latissimus dorsi muscle. 5, The deltoid muscle. 7, The
external oblique muscle. 8, The gluteus medius muscle. 9, The gluteus
maximus muscle, 11, 12, The rhomboideus major and minor muscles. 15, The
vertebral aponeurosis. 16, The serratus posticus inferior muscle. 22, The
serratus magnus muscle. 23, The internal oblique muscle.
_Practical Explanation._ The muscles 1, 11, 12, draw the scapula back
toward the spine. The muscles 11, 12, draw the scapula upward toward the
head, and slightly backward. The muscle 4 draws the arm by the side, and
backward, The muscle 5 elevates the arm. The muscles 8, 9, extend the
thigh on the body. The muscle 1 draws the head back and elevates the
chin. The muscle 16 depresses the ribs in expiration. The muscle 22
elevates the ribs in inspiration.]
159. The diaphragm, or midriff, is the muscular division between the
thorax and the abdomen. It is penetrated by the oesophagus on its way
to the stomach, by the aorta conveying blood toward the lower
extremity, and by the ascending vena cava, or vein, on its way to the
heart.
[Illustration: Fig. 42. A representation of the under, or abdominal side
of the diaphragm. 1, 2, 3, 4, The portion which is attached to the margin
of the ribs. 8, 10, The two fleshy pillars of the diaphragm, which are
attached to the third and fourth lumbar vertebrae. 9, The spinal column.
11, The opening for the passage of the aorta. 12, The opening for the
oesophagus. 13, The opening for the ascending vena cava, or vein.]
_Observation._ The diaphragm may be compared to an inverted basin, its
bottom being turned upward into the thorax, while its edge corresponds
with the outline of the edges of the lower ribs and sternum. Its
concavity is directed toward the abdomen, and thus, this cavity is
very much enlarged at the expense of that of the chest, which is
diminished to an equal extent.
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159. Describe the diaphragm. What vessels penetrate this muscular
septum?
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160. "The motions of the fingers do not merely result from the action
of the large muscles which lie on the fore-arm, these being concerned
more especially in the stronger actions of the hands. The finer and
more delicate movements of the fingers are performed by small muscles
situated in the palm and between the bones of the hand, and by which
the fingers are expanded and moved in all directions with wonderful
rapidity."
[Illustration: Fig. 43. A front view of the superficial layer of muscles
of the fore-arm. 5, The flexor carpi radialis muscle. 6, The palmaris
longus muscle. 7, One of the fasciculi of the flexor sublimis digitorum
muscle, (the rest of the muscle is seen beneath the tendons of the
pintails longus.) 8, The flexor carpi ulnaris muscle. 9, The palmar
fascia. 11, The abductor pollicis muscle. 12, One portion of the flexor
orevis pollicis muscle. 13, The supinator longus muscle. 14, The extensor
ossis metacarpi, and extensor primi internodii pollicis muscles, curving
around the lower border of the fore-arm. 15, The anterior portion of the
annular ligament, which binds the tendons in their places.
_Practical Explanation._ The muscles 5, 6, 8, bend the wrist on the bones
of the fore-arm. The muscle 7 bends the second range of finger-bones on
the first. The muscle 11 draws the thumb from the fingers. The muscle 12
flexes the thumb. The muscle 13 turns the palm of the hand upward. The
muscles 8, 13, 14, move the hand laterally.]
[Illustration: Fig. 44. A back view of the superficial layer of muscles
of the fore-arm. 5, The extensor carpi radialis longior muscle. 6, The
extensor carpi radialis brevior muscle. 7, The tendons of insertion of
these two muscles. 8, The extensor communis digitorum muscle. 9, The
extensor minimi dlgiti muscle. 10, The extensor carpi ulnaris muscle. 13,
The extensor ossis metacarpi and extensor primi internodii muscles, lying
together. 14, The extensor secundi internodii muscle; its tendon is seen
crossing the two tendons of the extensor carpi radialis longior and
brevior muscles. 15, The posterior annular ligament. The tendons of the
common extensor muscle of the fingers are seen on the back of the hand,
and their mode of distribution on the back of the fingers.
_Practical Explanation._ The muscles 5, 6, 10, extend the wrist on the
fore-arm. The muscle 8 extends the fingers. The muscle 9 extends the
little finger. The muscles 13 extend the metacarpal bone of the thumb,
and its first phalanx. The muscle 14 extends the last bone of the thumb.
The muscles 10, 13, 14, move the hand laterally.]
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160. Where are the muscles situated that effect the larger movements
of the hand? That perform the delicate movements of the fingers? Give
the use of some of the muscles represented by fig. 43. Those
represented by fig. 44.
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CHAPTER IX.
PHYSIOLOGY OF THE MUSCLES.
161. The muscles exercise great influence upon the system. It is by
their contraction that we are enabled to pursue different employments.
By their action the farmer cultivates his fields, the mechanic wields
his tools, the sportsman pursues his game, the orator gives utterance
to his thoughts, the lady sweeps the keys of the piano, and the young
are whirled in the mazy dance. As the muscles bear so intimate a
relation to the pleasures and employments of man, a knowledge of the
laws by which their action is governed, and the conditions upon which
their health depends, should be possessed by all.
162. The peculiar characteristic of muscular fibres is _contractility_,
or the power of shortening their substance on the application of
stimuli, and again relaxing when the stimulus is withdrawn. This is
illustrated in the most common movements of life. Call into action the
muscles that elevate the arm, by the influence of the _will_, or mind,
(the common stimulus of the muscles,) and the hand and arm are
raised; withdraw this influence by a simple effort of the will, and
the muscles, before rigid and tense, become relaxed and yielding.
163. The contractile effect of the muscles, in producing the varied
movements of the system, may be seen in the bending of the elbow.
The tendon of one extremity of the muscle is attached to the
shoulder-bone, which acts as a fixed point; the tendon of the
other extremity is attached to one of the bones of the fore-arm. When
the swell of the muscle contracts, or shortens, its two extremities
approach nearer each other, and by the approximation of the
terminal extremities of the muscle, the joint at the elbow bends.
On this principle, all the joints of the system are moved. This is
illustrated by fig. 45.
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161-172. _Give the physiology of the muscles._ 161. What are some of
the influences exerted by the muscles on the system? 162. What is
peculiar to muscular fibres? How is this illustrated? 163. Explain how
the movements of the system are effected by the contraction of the
muscles.
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[Illustration: Fig. 45. A representation of the manner in which all of
the joints of the body are moved. 1, The bone of the arm above the elbow.
2, One of the bones below the elbow. 3, The muscle that bends the elbow.
This muscle is united, by a tendon, to the bone below the elbow, (4,) at
the other extremity, to the bone above the elbow, (5,) 6, The muscle that
extends the elbow. 7, Its attachment to the point of the elbow. 8, A
weight in the hand to be raised. The central part of the muscle 3
contracts, and its two ends are brought nearer together. The bones below
the elbow are brought to the lines shown by 9, 10, 11. The weight is
raised in the direction of the curved line. When the muscle 6 contracts,
the muscle 3 relaxes and the fore-arm is extended.]
_Experiments._ 1st. Clasp the arm midway between the shoulder and
elbow, with the thumb and fingers of the opposite hand. When the arm
is bent, the inside muscle will become hard and prominent, and its
tendon at the elbow rigid, while the muscle on the opposite side will
become flaccid. Extend the arm at the elbow, and the outside muscle
will swell and become firm, while the inside muscle and its tendon at
the elbow will be relaxed.
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Explain fig. 45. Give experiment 1st.
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2d. Clasp the fore-arm about three inches below the elbow, then open
and shut the fingers rapidly, and the swelling and relaxation of the
muscles on the opposite sides of the arms, alternating with each
other, will be felt, corresponding with the movement of the fingers.
While the fingers are bending, the inside muscles swell, and the
outside ones become flaccid; and, while the fingers are extending, the
inside muscles relax, and the outside ones swell. The alternate
swelling and relaxation of antagonist muscles may be felt in the
different movements of the limbs.
164. Each fibre of the several muscles receives from the brain, through
the nervous filament appropriated to it, a certain influence, called
nervous fluid, or stimulus. It is this that induces contraction, while
the suspension of this stimulus causes relaxation of the fibres. By
this arrangement, the action of the muscular system, both as regards
duration and power, is, to a limited extent, under the control of the
mind. The more perfect the control, the better the education of the
muscular system; as is seen in the graceful, effective, and
well-educated movements of musicians, dancers, skaters, &c.
165. The length of time which a muscle may remain contracted, varies.
The duration of the contraction of the voluntary muscles, in some
measure, is in an inverse ratio to its force. If a muscle has
contracted with violence, as when great effort is made to raise a
heavy weight, relaxation will follow sooner than when the contraction
has been less powerful, as in raising light bodies.
166. The velocity of the muscular contraction depends on the will.
Many of the voluntary muscles in man contract with great rapidity, so
that he is enabled to utter distinctly fifteen hundred letters in a
minute; the pronunciation of each letter requiring both relaxation and
contraction of the same muscle, thus making three thousand actions in
one minute. But the contraction of the muscles of some of the inferior
animals surpasses in rapidity those of man. The race-horse, it is
said, has run a mile in a minute; and many birds of prey will probably
pass not less than a thousand miles daily.
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Give experiment 2d. 164. With what is each muscular fibre supplied?
What effect has this stimulus on the muscles? 165. how long does a
voluntary muscle remain contracted? 166. On what is the velocity of
muscular contraction dependent? How many letters may be pronounced in
a minute?
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167. The functions of the involuntary muscles are necessary the
digestion of food, the absorption and circulation of the nutritive
fluids. They could not be trusted with safety to the control of the
will, lest the passions or the indiscretions of the person should
continually avert those operations so necessary to health, and even to
life. The Divine Builder of this complicated machine has wisely
ordered that the muscles upon which these motions depend, shall act
under the impression of their proper stimulants, without the control
of the individual.
168. Again, there are certain operations which could not be safely
intrusted to the absolute government of the voluntary muscles, or
entirely removed from their control. Thus life can be supported only a
few minutes without breathing; but it would be impossible to perform
the daily vocations of life if we were compelled to breathe at all
times, or at perfectly regular intervals.
169. It has been observed that, among men of the same size, a wide
difference exists in their strength and activity--qualities which
depend upon the size and number of the nerves, the size and activity
of the brain, and the education, or training of the muscles. Men
having large nerves leading to the muscles, with the brain active,
and muscles well trained will perform feats of strength and agility,
that other men, of the same size, cannot effect. Rope-dancers,
harlequins, and other performers of feats, are persons thus
constituted.
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How many contractions and relaxations of the same muscle? What is said
of the rapidity of muscular contractions in other animals? 167. When
are the involuntary muscles called into action? Why would it not have
been safe to trust these important operations to the exclusive control
of the will? 168. Give an instance where some of the muscles act under
the government of the will, conjoined with those that are involuntary.
169. On what does the difference in muscular activity and strength
depend?
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170. Persons with small muscles, and largely developed nervous
systems, will sometimes exhibit very great muscular power for a time;
but it will not be of long continuance, unless the brain is
functionally diseased, as in hysteria, delirium of fever, insanity,
&c. Men of large muscles and small nerves can never perform feats of
great strength; but they have the power of endurance, and are better
capacitated for continued labor. Thus we cannot judge of the ability
of persons to make exertions and continue them, by their stature
alone. Strength, and the power of endurance, are the result of a
combination of well-developed muscles, large nerves, and a full-sized,
healthy, and active brain.
_Observation._ The muscles of fishes are large, and the nerves
distributed to them, comparatively small. The muscles of birds are
small, but their fibres are very compact. The nerves appropriated to
the muscles that are called into action in flying, are large as well
as numerous.
171. The contractile portion of a muscle is, in general, at a distance
from the part to be moved. Thus the principal muscles that move the
fingers are situated upon the forearm; and when the limb is nearly or
quite extended, the angle formed by the part to be moved and the
contractile muscles is small. Again, the attachment of the muscles to
the part to be moved is near the joint that forms the fulcrum, (fig.
45.) By these arrangements there is a loss of power; but we are
compensated for this disadvantage by increased celerity of movement,
beauty of form, and adaptation of the limbs to the varied pursuits of
man.
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170. What is said of those persons who have small muscles and largely
developed nervous systems? Of those who have large muscles and small
nerves? Upon what do strength and the power of endurance depend? 171.
Why is there a loss of power in the action of the muscles?
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_Illustration._ The muscle that bends the elbow acts at disadvantage,
and this is greatest when the arm is nearly or quite extended, as the
angle of action is then least. This disadvantage is further increased
by the attachment of the motive muscles near the joint.
172. The number of muscles which are called into action in the
movements of the different joints, varies. The hinge-joints, as the
elbow, have two sets of muscles--one to bend the joint, the other to
extend it. The ball and socket joints, as the shoulder, are not
limited to mere flexion and extension. No joint in the system has the
range of movement that is possessed by that of the shoulder. By the
action of the muscles attached to the arm, it is not only carried
upward and forward, but forward and backward. Hence the arm may be
moved at any angle, by a combined action of its muscles.
_Observation._ "Could we behold properly the muscular fibres in
operation, nothing, as a mere mechanical exhibition, can be conceived
more superb than the intricate and combined actions that must take
place during our most common movements. Look at a person running or
leaping, or watch the motions of the eye. How rapid, how delicate, how
complicated, and yet how accurate, are the motions required! Think of
the endurance of such a muscle as the heart, that can contract, with a
force equal to sixty pounds, seventy-five times every minute, for
eighty years together, without being weary."
_Note._ It would be a profitable exercise for pupils to press their
fingers upon prominent muscles, and, at the same time, vigorously
contract them, not only to learn their situations, but their use; as
the one that bends the arm, 14, fig. 46.
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How is this illustrated? 172. Do all joints require the same number of
muscles, when called into action? How many are called into action in
the movement of the elbow? What is their office? What is said of the
movement of the ball and socket joint?
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[Illustration: Fig. 46. An anterior view of the muscles of the body. 1.
The frontal swell of the occipito-frontalis. 2, The orbicularis
palpebrarum. 3, The levator labli superioris. 4, The zygomaticus major.
5, The zygomaticus minor. 6, The masseter. 7, The orbicularis oris. 8,
The depressor labli inferioris. 9. The platysma myodes. 10, The deltoid.
11, The pectoralis major. 12, The latissimus dorsi. 14, The biceps flexor
cubiti. 15, The triceps extensor cubiti. 16, The supinator radii longus.
18, The flexor carpi radialis longior. 19, The flexor communis digitorum.
20, The annular ligament. 21, The palmar fascia. 22, The obliquus
externus abdominis. 26, The psoas magnus. 27, The adductor longus. 28,
The sartorius. 29, The rectus femoris. 30, The vastus externus. 31, The
vastus internus. 32, The tendon patellae. 33, The gastrocnemius. 34, The
tibialis anticus. 36, The tendons of the extensor digitorum communis.]
[Illustration: Fig. 47. A posterior view of the muscles of the body. 3,
The complexus. 4, The splenius. 5, The masseter. 6, The sterno-cleido
mastoideus. 7, The trapezius. 8, The deltoid. 10, The triceps extensor.
13, The tendinous portion of the triceps. 14, The anterior edge of the
triceps. 15, The supinator radii longus. 17, The extensor communis
digitorum. 18, The extensor ossis metacarpi pollicis. 19, The tendons of
the extensor communis digitorum. 20, The olecranon process of the ulna
and insertion of the triceps. 21, The extensor carpi ulnaris. 22, The
extensor communis digitorum. 24, The latissimus dorsi. 25, Its tendinous
origin. 26, The obliquus externus. 27, The gluteus medius. 28, The
gluteus magnus. 29, The biceps flexor cruris. 30, The semi-tendinosus.
31, 32, The gastrocnemius. 33, The tendo Achillis.
_Practical Explanation._ The muscle 1, fig. 46, by its contraction,
raises the eyebrows. The muscle 2, fig. 46, closes the eyelids. The
muscle 3, fig. 46, elevates the upper lip. The muscles 4, 5, fig. 46,
elevate the angles of the mouth. The muscles 6, fig. 46, and 5, fig. 47,
bring the teeth together. The muscle 7, fig. 46, closes the mouth. The
muscle 8, fig. 46, depresses the lower lip. The muscles 9, fig. 46, and
6, fig. 47, bend the neck forward. The muscles 3, 4, fig. 47, elevate the
head and chin. The muscle 22, fig. 46, bends the body forward, and draws
the ribs downward. The muscle 11, fig. 46, brings the shoulder forward.
The muscle 7, fig. 47, draws the shoulder back. The muscles 10, fig. 46,
and 8, fig. 47, elevate the arm. The muscles 11, fig. 46, and 24, fig.
47, bring the arm to the side. The muscle 14, fig. 46, bends the arm at
the elbow. The muscle 10, fig. 47, extends the arm at the elbow. The
muscles 16, 18, fig. 46, bend the wrist and fingers. The muscle 19 bends
the fingers. The muscles 18, 21, 23, fig. 47, extend the wrist. The
muscle 23, fig. 47, extends the fingers. The muscles 26, 27, 28, fig. 46,
bend the lower limbs on the body, at the hip. The muscle 28, fig. 46,
draws one leg over the other, (the position of a tailor when sewing.) The
muscles 27, 28, fig. 47, extend the lower limbs on the body, at the hip.
The muscles 29, 30, 31, fig. 46, extend the leg at the knee. The muscles
29, 30, fig. 47, bend the leg at the knee. The muscles 34, 36, fig. 46,
bend the foot at the ankle, and extend the toes. The muscles 31, 32, 33,
fig. 47, extend the foot at the ankle.]
_Note._ Let the anatomy and physiology of the muscular system be
reviewed, in form of topics, from figs 46, 47, or from the anatomical
outline plates No. 3 and 4.
CHAPTER X.
HYGIENE OF THE MUSCLES
173. _The muscles should be used, in order that the size and strength
of these organs may be adequate to the demand made upon them._ It is a
law of the system that the action and power of an organ are
commensurate, to a certain extent, with the demand made upon it; and
it is a law of the muscular system that, whenever a muscle is called
into frequent use, its fibres increase in thickness within certain
limits, and become capable of acting with greater force; while, on the
contrary, the muscle that is little used decreases in size and power.
_Illustrations._ 1st. The blacksmith uses and rests the muscles of his
arm when striking upon the anvil. They not only increase in size, but
become very firm and hard.
2d. The student uses the muscles of the arm but little, in holding his
books and pen; they not only become small, but soft.
3d. Let the student leave his books, and wield an iron sledge, and the
muscles of his arm will increase in size and firmness. On the other
hand, let the blacksmith assume the student's vocation, and the
muscles of his arm will become soft and less firm.
174. _When the muscles are called into action, the flow of blood in
the arteries and veins is increased._ The increased flow of blood in
the arteries and veins, causes a more rapid deposition of the
particles of matter of which the muscles are composed. If the
exercise is adequate to the power of the system, the deposit of new
material will exceed in quantity the particles of matter removed, and
both the size and energy of the muscles are increased. But there is a
limit to the muscles becoming strong by labor. Sooner or later, man
will attain his growth or power; yet by judicious exercise, care, and
discreet management, the greatest power of the muscles may be
preserved until advanced age.
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173-211. _Give the hygiene of the muscles._ 173. What is necessary
that muscles may attain size and strength? Give a law of the muscular
system. Show this by practical illustrations. 174. Why do muscles
increase in size when exercised?
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175. _The muscles are lessened in size and diminished in power when
the exercise is continued so as to produce a feeling of exhaustion._
The loss of material, in this instance, will exceed the deposition of
the atoms of matter. This is seen in the attenuated frames of
over-tasked domestic animals, as the horse. The same truth is
illustrated by the laborious agriculturist, who, in consequence of too
severe toil while gathering the products of the field, frequently
diminishes his weight several pounds in a few weeks. Exercise, either
for pleasure or profit, may fatigue, yet it should never be protracted
to languor or exhaustion, if the individual desires "a green old
age."
176. _The same amount of exercise will not conduce to the health of
all individuals._ If riding or walking one mile causes slight fatigue,
this may be beneficial; while, by travelling two miles, the exhaustion
may be highly injurious. Exercise and labor should be adapted to the
strength of particular individuals. How little soever the strength,
that must be the measure of exertion. Any other rule would be fatal to
the hopes of invigorating the system, either by exercise or labor.
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Is there a limit to the muscles becoming powerful by action? How may
the strength of muscles be kept until advanced age? 175. What is the
effect when exercise is continued until there is a feeling of
exhaustion? Give a practical illustration. What rule is mentioned in
regard to exercise? 176. Can all persons take the same amount of
exercise? What rule is given as to the amount of exercise?
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177. _Relaxation must follow contraction, or, in other words, rest
must follow exercise._ The necessity of relaxation, when a muscle has
been called into action, is seen in the example of a boy extending his
arm with a book in his hand, as a penalty. The boy can keep the arm
extended but a short time, make what effort he may. It is also seen in
the restlessness and feverish excitement that are evinced by persons
gazing on troops during days of review. The same is noted in shopping.
Such employments call into action the muscles that support the spinal
column in an erect position, and the languor or uneasiness is muscular
pain. The long-continued tension of a muscle enfeebles its action, and
eventually destroys its contractility.
178. _In school, the small children, after sitting a short time,
become restless._ If their position be changed, their imperfectly
developed muscles will acquire tone, and will again support the spinal
column erect without pain. The necessity for frequent recesses in
school, is founded on the organic law of muscular action alternating
with rest. The younger and feebler pupils are, the greater the
necessity for frequent recesses. We would not have the teacher think
that one half of the time should be spent in recesses; or the mother,
that her daughter is going to school to play. But we do maintain that
recesses should be given, and that they should be short and frequent,
especially for small and feeble scholars.
179. _Exhaustion is the inevitable result of continued muscular
contraction._ For example, let a lady ply the needle quickly for some
hours, and the muscles of the back and right arm will become
exhausted, which will be indicated by a sense of weariness in these
parts. A change of employment and position calls into action a
different set of muscles, and the exhausted organs are relieved.
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177. What is said of the contraction and relaxation of the muscles?
Give examples of the necessity of relaxing the muscles. 178. Why
should not small children be confined in one position for a long time?
What evils result from this practice? What class of pupils should have
recesses most frequently? 179. What effect has continued muscular
contraction?
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180. _Much more labor will be accomplished by taking time to relax the
exhausted muscles_, or by so changing the employment as to bring into
action a new set of muscles; the woodman thus relieves himself, by
sawing and splitting alternately. This principle applies to the labor
of the horse and ox; and it is also applicable to all kinds of
employment. With the invalid convalescing from fever, relapses result
from inattention to these laws. When a patient is recovering from
sickness, his physician should take care that his exercise be proper,
neither too much, too little, nor too long continued.
181. _The muscles of growing youths will not endure so much exercise
or labor as those of mature men._ In youth a portion of the vital, or
nervous energy of the system, is expended upon the growth of the
organs of the body, while in the individual who has attained his
growth, this expenditure is not demanded; consequently severe labor or
exercise should not be imposed on growing children.
_Observation._ In the campaigns of Napoleon Bonaparte, his army was
frequently recruited by mere boys. He complained to the French
government, because he was not supplied with men of mature years, as
the youths could not endure the exertion of his forced marches.
182. _The muscles should be gradually called into action._ These
organs in action require more blood and nervous fluid than when at
rest. As the circulation of these fluids can only be increased in a
gradual manner, it follows, that, when the muscular system has been in
a state of rest, it should not suddenly be called into vigorous
action. On arising from a bed, lounge, or chair, the first movements
of the limbs should be slow, and then gradually increased.
_Observation._ if a man has a certain amount of work to perform in
nine hours, and his muscles have been in a state of rest, he will do
it with less fatigue by performing half the amount of the labor in
five hours, and the remainder in four hours. The same principle should
be regarded in driving horses and other beasts of burden.
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180. How can the greatest amount of labor be secured with the least
exhaustion to the muscles? 181. Why should not severe labor be imposed
on growing children? 182. How should the muscles be called into
action?
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183. _The muscles should be rested gradually, when they have been
vigorously used._ If a person has been making great muscular exertion
in cutting wood, or any other employment, instead of sitting down to
rest, he should continue muscular action, for a short time, by some
moderate labor or amusement.
184. _If the system has been heated by muscular action, and the skin
is covered with perspiration, avoid sitting down_ "to cool" in a
current of air; rather, put on more clothing, and continue to exercise
moderately. In instances when severe action of the muscles has been
endured, bathing and rubbing the skin of the limbs and joints that
have been used, are of much importance. The laboring agriculturist and
industrious mechanic, by reducing to practice this suggestion, would
thus prevent soreness of the muscles, and stiffness of the joints.
185. _The muscles should be abundantly supplied with pure blood._ This
state of the circulating fluid requires a healthy condition of the
digestive apparatus, and that the skin should be kept warm by proper
clothing, clean by bathing, and be acted upon by pure air and good
light; the movements of the ribs and diaphragm should be unrestricted,
and the lungs should have ample volume and be supplied with pure air.
In all instances, muscular power is greatest when the preceding
conditions exist, as the muscles are then stimulated by pure blood;
consequently, it is of practical importance to the mechanic, the
farmer, the man of leisure, and not less so to the ladies, to observe
these conditions, whatever vocation of life they pursue.
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183. How should the muscles be rested when they have been vigorously
used? 184. What precaution is given when the skin is covered with
perspiration? How may soreness of the muscles, consequent upon severe
action, be prevented? 185. Should the muscles be supplied with pure
blood? When is muscular power the greatest?
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186. _The muscles should be used in pure air._ The purer the air we
breathe, the more stimulating the blood supplied to the muscles, and
the longer they can be used in labor, walking, or sitting, without
fatigue and injury; hence the benefit derived in thoroughly
ventilating all inhabited rooms. For the same reason, if the air of
the sick-room is pure, the patient will sit up longer than when the
air is impure.
_Observation._ It is a common remark that sick persons will sit up
longer when riding in a carriage, than in an easy chair in the room
where they have lain sick. In the one instance, they breathe pure air;
in the other, usually, a confined, impure air.
187. _The muscles should be exercised in the light._ Light,
particularly that of the sun, exercises more or less influence on man
and the inferior animals as well as on plants. Both require the
stimulus of this agent. Shops occupied by mechanics, kitchens, and
sitting-rooms, should be well lighted, and situated on the sunny side
of the house. Cellar kitchens and underground shops should be avoided.
For similar reasons, students should take their exercise during the
day, rather than in the evening, and, as much as possible, laborers
should avoid night toil.
_Illustrations._ Plants that grow in the shade, as under trees, or in
a dark cellar, are of lighter color and feebler than those that are
exposed to the light of the sun. Persons that dwell in dark rooms are
paler and less vigorous than those who inhabit apartments well
lighted, and exposed to the rays of the sun.
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186. Why should the muscles be used in pure air? Give a common
observation. 187. What effect has light on the muscular system? What
should the laborer avoid? Why should not students take their daily
exercise in the evening? How is the influence of solar light
illustrated?
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188. _Exercise should be regular and frequent._ The system needs this
means of invigoration as regularly as it does new supplies of food. It
is no more correct that we devote several days to a _proper_ action of
the muscles, and then spend one day inactively, than it is to take a
_proper_ amount of food for several days, and then withdraw this
supply for a day. The industrious mechanic and the studious minister
suffer as surely from undue confinement as the improvident and
indolent. The evil consequences of neglect of exercise are gradual,
and steal slowly upon an individual. But sooner or later they are
manifested in muscular weakness, dyspepsia, and nervous irritability.
_Observation._ The custom among farmers of enduring severe and undue
toil for several successive days, and then spending one or two days in
idleness to _rest_, is injudicious. It would be far better to do less
in a day, and continue the labor through the period devoted to
idleness, and then no rest will be demanded.
189. _Every part of the muscular system should have its appropriate
share of exercise._ Some employments call into exercise the muscles of
the upper limbs, as shoe-making; others, the muscles of the lower
limbs; while some, the muscles of both upper and lower limbs, with
those of the trunk, as farming. In some kinds of exercise, the lower
limbs are mainly used, as in walking; in others, the upper limbs; and
again, the muscles of the trunk, together with those of the upper and
lower limbs, as in archery, quoits, playing ball. Those trades and
kinds of exercise are most salutary, in which all the muscles have
their due proportion of action, as this tends to develop and
strengthen them equally. Thus labor upon the farm and domestic
employment are superior as vocations, and archery, quoits, and
dancing, if the air is pure, among the pastimes. For sedentary
persons, that kind of exercise is best which calls into action the
greatest number of muscles.
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188. How should exercise be taken? What is said respecting irregular
exercise? Are the consequences of neglected exercise immediately
apparent? What practical observation is given? 189. Should every
muscle have its due amount of exercise? Mention some employments that
only call into action the muscles of the upper limbs. Those of the
lower limbs, those of the trunk and limbs. Mention, in the different
pastimes, what muscles are called into action.
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190. _The proper time for labor or exercise should be observed._ This
is modified by many circumstances. As a general rule, the morning,
when the air is pure and the ground dry, is better than the evening;
for then, the powers of the body are greatest. Severe exercise and
labor should be avoided immediately before or after eating a full
meal, for the energies of the system are then required to perform the
digestive function. For similar reasons, it is not an appropriate time
for energetic muscular action immediately before or after severe
mental toil, as the powers of the system are then concentrated upon
the brain.[6]
[6] It appears to be a fact, that no two important organs can be
called into intense action at the same time, without injury to
both, as well as to the general system. This arises from the
circumstance that an organ, when in functional action, attracts
fluids (sanguineous and nervous) from other organs of the
system. Except in a few instances of high health in youth, the
power of the system is not adequate to supply more than one
organ in action with the appropriate fluids at the same time.
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What kinds of exercise are best? 190. What rule is given respecting
the time for exercise? 191. Why do the muscles require sleep? What is
the effect of an inversion of the law of rest?
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191. _The muscles require sleep to restore their expended energies._
Among the arrangements of creative wisdom, no one harmonizes with the
wants of the system more than the alternation of day and night. The
natural inclination of man to sleep, is in the stilly hour of night,
when all nature reposes, and to be in action during the light of day.
An inversion of this law of rest causes greater exhaustion of the
system than the same amount of exertion during daylight. This is
illustrated by the wearied and exhausted condition of watchers,
night-police, and other individuals who spend a part of the night in
some active business of life.
192. _The muscles should not be compressed._ Compression prevents the
blood from passing to the muscles with freedom; consequently, they are
not supplied with material to renovate and promote their growth.
Again, pressure stimulates the lymphatics to action; and by the
increased activity of these vessels the muscles are attenuated. In the
case of a man with a fractured limb, the muscles are not only
enfeebled by inaction, but diminished in size by compression from the
dressing. Limbs enfeebled in this way will not recover their size,
tone, and strength, until the bandages are removed, and a proper
amount of exercise taken.
193. The pressure of tight dresses, under the name of a "snug fit,"
enfeebles the muscles of the back, and is a common cause of projecting
shoulders and curvature of the spinal column. Thus every appendage to
the dress of ladies which prevents free motion of the muscles of the
chest and spinal column, weakens the muscles thus restrained, and not
only prevents the proper expansion of the lungs, but, by weakening the
muscles which sustain the spine, induces curvature and disease.
Whalebone, wood, steel, and every other unyielding substance, should
be banished from the toilet, as enemies of the human race.
194. _The mind exerts a great influence upon the tone and contractile
energy of the muscular system._ A person acting under a healthy mental
stimulus will make exertion with less fatigue than he would without
this incentive. For this reason, a sportsman will pursue his game
miles without fatigue, while his attendant, not having any mental
stimulus, will become weary. Again, if the sportsman spends some hours
in pursuit of his favorite game without success, a feeling of languor
creeps over him; but while he is thus fatigued and dispirited, let him
catch a glimpse of the game,--his wearied feelings are immediately
dissipated, and he presses on with renewed energy and recruited
strength.
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192. Why should not the muscles be compressed? 193. What is the effect
of tight clothing upon the muscles? 194. What is said of the influence
of the mind upon muscular activity? Give an illustration of mental
stimulus cooperating with muscular activity in the case of a
sportsman.
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195. This principle was well illustrated in the retreat from Russia of
the defeated and dispirited French army. When no enemy was near,
they had hardly strength sufficient to carry their arms; but no
sooner did they hear the report of the Russian guns, than new life
seemed to pervade them, and they wielded their weapons powerfully
until the foe was repulsed, then there was a relapse to weakness, and
prostration followed. It is thus with the invalid when riding for
his health;--relate an anecdote, or excite this mental stimulus by
agreeable conversation, and much benefit will accrue from the ride
to the debilitated person. So it is in the daily vocations of
life; if the mind have some incentive, the tiresomeness of labor
will be greatly diminished. Let an air of cheerfulness ever pervade
our every employment, and, like music, "it sweetens toil."
196. Facts illustrative of the inutility of calling the muscles into
action, without the cooperation of the mind, are seen in the
spiritless aspect of many of our boarding school processions, when a
walk is taken merely for exercise, without having in view any
attainable object. But present to the mind a botanical or geological
excursion, and the saunter will be exchanged for the elastic step, the
inanimate appearance for the bright eye and glowing cheek. The
difference is, simply, that, in the former case, the muscles are
obliged to work without that full nervous impulse so essential to
their energetic action; and that, in the latter, the nervous influence
is in full and harmonious operation.
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195. Give an illustration of mental stimulus cooperating with muscular
activity in the case of the dispirited French army in their retreat
from Russia. How can a union of mental impulse and muscular action be
beneficial to an invalid? Does this same principle apply to those who
labor? 196. Give an instance of the different effects produced by the
absence and presence of the mental stimulus.
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197. It must not, however, be supposed that a walk simply for the sake
of exercise can never be beneficial. Every one, unless prevented by
disease, should consider it a duty to take exercise every day in the
open air; if possible, let it be had in combination with harmonious
mental exhilaration; if not, let a walk, in an erect position, be made
so brisk as to produce rapid respiration and circulation of the blood,
and in a dress that shall not interfere with free motions of the arms
and free expansion of the chest.
_Observation._ The advantages of combining harmonious mental
excitement, with muscular activity, is thus given by Dr. Armstrong:--
"_In whate'er you sweat,
Indulge your taste._ Some love the manly toils
The tennis some, and some the graceful dance;
Others, more hardy, range the purple heath
Or naked stubble, where, from field to field,
The sounding covies urge their lab'ring flight,
Eager amid the rising cloud to pour
The gun's unerring thunder; and there are
Whom still the mead of the green archer charm.
_He chooses best whose labor entertains
His vacant fancy most; the toil you hate
Fatigues you soon, and scarce improves your limbs._"
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197. May not a walk, simply as an exercise, be beneficial? What is
preferred?
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CHAPTER XI.
HYGIENE OF THE MUSCLES, CONTINUED.
198. _The erect attitude lessens the exhaustion of the muscles._ A
person whose position is erect will stand longer, walk further, and
perform more labor, than an individual whose position is stooping, but
equal in all other respects. The manly port in an erect attitude,
depends chiefly upon the action of the muscles of the back; and it
follows that the fewer the muscles in a state of tension, the less the
draught upon the nervous system, and the less its exhaustion. Another
advantage which attends the erect position is, the trunk and head are
balanced upon the bones and cartilages of the spinal column. If the
body slightly incline forward, the muscles attached to the posterior
side of the spine, by a gentle contraction, will bring it to the
perpendicular, and even incline it backward. This is immediately
removed by a slight contraction of the muscles upon the anterior side
of the spinal column.
199. In the erect position, there is a constant slight oscillation
of the body backward and forward, like the movement of a pendulum;
while, in the stooping posture, the muscles on the posterior side
of the spinal column are kept in a state of continued tension and
contraction, to prevent the body from falling forward. This enfeebles
the muscles of the back, and exhausts the nervous energy, while the
erect position favors their development and power, because there is
an alternate contraction and relaxation of the muscles. Again, in the
stooping position, the lower limbs are curved at the knee. In this
attitude, there is a constant tension of the muscles of the lower
extremities, which produces muscular exhaustion.
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198. Why will a person who stands erect walk further, and perform more
labor, than if he assumed the stooping posture? 199. Why are the
muscles of the back so soon exhausted in the stooping position?
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[Illustration: Fig. 48. 1, A perpendicular line from the centre of the
feet to the upper extremity of the spinal column, where the head rests.
2, 2, 2, The spinal column, with its three natural curves. Here the head
and body are balanced upon the spinal column and joints of the lower
extremities, so that the muscles are not kept in a state of tension. This
erect position of the body and head is always accompanied with straight
lower limbs.]
[Illustration: Fig. 49. 1, A perpendicular line from the centre of the
feet. 2, Represents the unnatural curved spinal column, and its relative
position to the perpendicular, 1. The lower limbs are curved at the knee,
and the body is stooping forward. While standing in this position, the
muscles of the lower limbs and back are in continued tension, which
exhausts and weakens them.]
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What is represented by figs. 48 and 49?
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200. When it is necessary to call into action a part of the muscles of
the system in the performance of any duty, as those of the lower limbs
in walking, if the muscles of other parts are in a state of inaction,
the influence of the nervous system can be determined in an undivided
manner upon those parts of the lower limbs in action; hence they will
not so soon become wearied or exhausted, as when this influence is
divided between a greater number of muscles. In performing any labor,
as in speaking, reading, singing, mowing, sewing, &c., there will be
less exhaustion, and the effort can be longer maintained in the erect
position of the body and head, than in a stooping attitude.
_Experiment._ Hold in each hand a pail of water or equal weights, in a
stooping posture, as long as it can be done without much suffering and
injury. Again, when the muscular pain has ceased, hold the same pails
of water, for the same length of time, in an erect posture, and note
the difference in the fatigue of the muscles.
201. If the stooping posture is acquired in youth, we are quite
certain of seeing the deformed shoulders in old age. Hence the
importance of duly exercising the muscles of the back, for when they
are properly developed, the child can and will stand erect. In this
attitude, the shoulders will be thrown back, and the chest will become
broad and full.
202. Pupils, while standing during recitations, often inadvertently
assume the attitude represented by fig. 49, and it is the duty of
teachers to correct this position when assumed. When a child or adult
has contracted a habit of stooping, and has become round-shouldered,
it can be measurably, and generally, wholly, remedied by moderate and
repeated efforts to bring the shoulders back, and the spinal column in
an erect position. This deformity can and should be remedied in our
schools. It may take months to accomplish the desired end, yet it can
be done as well under the direction of the kind instructor, as under
the stern, military drill sergeant, who never fails to correct this
deformity among his raw recruits.
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200. What suggestion when it is necessary to call into action a part
of the muscular system? Give the experiment that illustrates this
principle. 201. Why should a child he taught to stand erect? 202. How
can round shoulders acquired by habit be remedied?
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[Illustration: Fig. 50. A proper position in sitting.]
203. _The child should be taught to sit erect when employed in study
or work._ This attitude favors a healthy action of the various organs
of the system, and conduces to beauty and symmetry of form. Scholars
are more or less inclined to lean forward and place the elbow on the
table or desk, for support and this is often done when their seats
are provided with backs. Where there is a predisposition to curvature
of the spine, no position is more unfavorable or more productive of
deformities than this; for it is usually continued in one direction,
and the apparent deformity it induces is a projection of the
shoulders. If the girl is so feeble that she cannot sit erect, as
represented by fig. 50, let her stand or recline on a couch; either is
preferable to the position represented by fig. 51. In furnishing
school-rooms, care should be taken that the desks are not so low as to
compel the pupils to lean forward in examining their books.
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203. Why should the erect attitude be assumed in sitting?
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[Illustration: Fig. 51. An improper position in sitting.]
204. _The muscles, when exhausted, cannot endure continued effort._
When the energies of the muscular system have been expended by severe
and long-continued exercise, or the brain and nervous system
prostrated by protracted mental effort, the muscles are unfitted to
maintain the body erect in standing or sitting for a long time, as the
nervous system, in its exhausted state, cannot supply a sufficient
amount of its peculiar influence to maintain the supporting muscles of
the body and head in a state of contraction. Hence, a child or adult,
when much fatigued, should not be compelled to stand or sit erect in
one posture, but should be permitted to vary the position frequently,
as this rests and recruits both the muscular and the nervous system.
205. _A slight relaxation of the muscles tends to prevent their
exhaustion._ In walking, dancing, and most of the mechanical
employments, there will be less fatigue, and the movements will be
more graceful, when the muscles are slightly relaxed. When riding in
cars or coaches, the system does not suffer so severely from the jar
if there is a slight relaxation of the muscles, as when they are in a
state of rigid contraction.
_Experiments._ Attempt to bow with the muscles of the limbs and trunk
rigid, and there will be a stiff bending of the body only at the
hip-joint. On the other hand, attempt to bow with the muscles
moderately relaxed; the ankle, the knee, and the hip-joint will
slightly bend, accompanied with an easy and graceful curve of the
body.
206. The muscles when relaxed, together with the yielding character of
the cartilage, and the porous structure of the ends of the bones that
form a joint, diffuse or deaden the force of jars, or shocks, in
stepping suddenly down stairs, or in falling from moderate heights.
Hence, in jumping or falling from a carriage, or any height, the shock
to the organs of the system may be obviated in the three following
ways: 1st. Let the muscles be relaxed, not rigid. 2d. Let the limbs be
bent at the ankle, knee, and hips; the head should be thrown slightly
forward, with the trunk a little stooping. 3d. Fall upon the toes, not
the heel.
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204. When are the muscles unfitted to maintain the system erect either
in standing or sitting? What is necessary when this condition of the
system exists? 205. Why should the muscular system be slightly relaxed
in walking, &c.? Give illustrative experiments. 206. What is the
reason that we do not feel the jar in falling from a moderate height?
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_Experiments._ Stand with the trunk and lower limbs firm, and the
muscles rigid; then jump a few inches perpendicularly to the floor,
and fall upon the heels. Again, slightly bend the limbs, jump a few
inches, and fall upon the toes, and the difference in the force of the
shock, to the brain and other organs, will be readily noticed.
207. _The muscles require to be educated, or trained._ The power of
giving different intonations in reading, speaking, singing, the varied
and rapid executions in penmanship, and all mechanical or agricultural
employments, depend, in a measure, upon the education of the muscles.
In the first effort of muscular education, the contractions of the
muscular fibres are irregular and feeble, as may be seen when the
child begins to walk, or in the first efforts of penmanship.
208. _Repetition of muscular action is necessary._ To render the
action of the muscles complete and effective, they must be called into
action repeatedly and at proper intervals. This education must be
continued until not only each muscle, but every fibre of the muscle,
is fully under the control of the will. In this way persons become
skilful in every employment. In training the muscles for effective
action, it is very important that correct movements be adopted at the
commencement. If this is neglected, the motions will be constrained
and improper, while power and skill will be lost.
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How is this shown by experiment? 207. Upon what do the different
intonations of sound or mechanical employments depend? Why are the
first efforts in educating the muscles indifferent or irregular? 208.
Why is repetition of muscular action necessary? Why is it important
that correct movements be adopted in the first efforts of muscular
education?
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_Illustration._ If a boy, while learning to mow, is allowed to swing
his scythe in a stooping position, twisting his body at every sweep of
the scythe, he will never become an easy, efficient mower. Proper
instruction is as necessary in many of the agricultural branches as in
the varied mechanical employments.
[Illustration: Fig. 52. An improper, but not an unusual position, when
writing.]
[Illustration: Fig. 53. A proper position, when writing.]
209. _Good penmanship requires properly trained muscles._ To a
deficient analysis of the movements of the arm, hand, and fingers, on
the part of teachers and pupils in penmanship, together with an
improper position in sitting, is to be ascribed the great want of
success in acquiring this art. The pen should be held loosely, and
when the proper position is attained, the scholar should make an
effort to imitate some definite copy as nearly as possible. The
movements of the fingers, hand, and arm, necessary to accomplish this,
should be made with ease and rapidity, striving, at each effort, to
imitate the copy more nearly.
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How is this illustrated? 209. Why have so many pupils failed in
acquiring good penmanship?
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210. When the arm, hand, and fingers are rigid, the large muscles,
that bend and extend these parts, are called into too intense action.
This requires of the small muscles, that produce the lateral
movements, which are essential to rapidity in writing, an effort which
they cannot make, or can with difficulty accomplish.
_Experiment._ Vigorously extend the fingers by a violent and rigid
contraction of the muscles upon the lower part of the arm, and the
lateral movement which is seen in their separation cannot be made. But
gently extend the fingers, and their oblique movements are made with
freedom.
211. An individual who is acquainted with the laws of health, whose
muscles are well trained, will perform a certain amount of labor with
less fatigue and waste to the system, than one who is ignorant of the
principles of hygiene, and whose muscles are imperfectly trained.
Hence the laboring poor have a deep interest in acquiring a knowledge
of practical physiology, as well as skill in their trade or vocation.
It is emphatically true to those who earn their bread by the "sweat of
their brow," that "knowledge is power."
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210. What is said of the lateral and oblique movements of the arm,
hand, and fingers in writing? How is this shown by experiment? 211.
Why is the study of physiology and hygiene of utility to the laborer?
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CHAPTER XII.
THE TEETH.
212. The teeth, in composition, nutrition, and growth, are different
from other bones of the body. They vary in number at different periods
of life, and, unlike other bones, they are exposed to the immediate
action of atmospheric air and foreign substances. The bones of the
system, generally, when fractured, unite; but there is never a
permanent union of a tooth when broken.
ANATOMY OF THE TEETH.
213. The TEETH are attached to the upper and lower jaw-bone, by means
of bony sockets, called _al've-o-lar_ processes. These give great
solidity to the attachment of the teeth, and frequently render their
extraction difficult. The gums, by their fibrous, fleshy structure,
serve to fix the teeth more firmly in the jaw.
_Observation._ When a _permanent_ tooth is extracted, these bony
processes are gradually absorbed, so that in advanced age there
remains only the jaw-bone covered by the lining membrane of the gum.
This accounts for the narrow jaw and falling in of the lips in old
age. Frequently, a piece of the alveolar process comes out with the
tooth when extracted, and the dentist has then the credit of "breaking
the jaw." No great injury results from the removal of the process in
this manner.
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212. What is said of the teeth? In what respect do they differ from
other bones of the body? 213-218. _Give the anatomy of the teeth._
213. What confines the teeth in the jaw-bone? What becomes of the
socket when a tooth is removed? What effect has this absorption upon
the jaw and lips?
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214. The teeth are formed in the interior of the jaws, and within
_dent'al cap'sules_, (membranous pouches,) which are enclosed within
the substance of the bone, and present in their interior a fleshy bud,
or granule, from the surface of which exudes the ivory, or the bony
part of the tooth. In proportion as the tooth is formed, it rises in
the socket, which is developed simultaneously with the tooth, and
passes through the gum, and shows itself without.
[Illustration: Fig. 54. 1, The body of the lower jaw. 2, Ramus, or branch
of the jaw, to which the muscles that move it are attached. 3, 3, The
processes which unite the lower jaw with the head. _i_, The middle and
lateral incisor tooth of one side. _b_, The bicuspid teeth. _c_, The
cuspids, or eye teeth. m, The three molar teeth. A, shows the relation of
the permanent to the temporary teeth.]
215. The first set, which appears in infancy, is called _tem'po-ra-ry_,
or milk teeth. They are twenty in number; ten in each jaw. Between
six and fourteen years of age, the temporary teeth are removed, and the
second set appears, called _per'ma-nent_ teeth. They number
thirty-two, sixteen in each jaw.
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214. Where and how are the teeth formed? Explain fig. 54. 215. What
are the first set called? How many in each jaw? The second set? How
many in number?
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216. The four front teeth in each jaw are called _in-ci'sors_,
(cutting teeth;) the next tooth in each side, the _cus'pid_, (eye
tooth;) the next two, _bi-cus'pids_, (small grinders;) the next two,
_mo'lars_, (grinders.) The last one on each side of the jaw is called
a _wisdom tooth_, because it does not appear until a person is about
twenty years old. The incisors, cuspids, and bicuspids, have each but
one root. The molars of the upper jaw have three roots, while those of
the lower jaw have but two.
[Illustration: Fig. 55. The permanent teeth of the upper and lower jaw.
_a_, _b_, The incisors. _c_, The cuspids. _d_, _e_, The bicuspids. _f_,
_g_, The molars, (double teeth.) _h_, The wisdom teeth.]
_Observation._ The shape of the teeth in different species of animals
is adapted to the kind of food on which they subsist. Those animals
that feed exclusively on flesh, as the lion, have the cuspids, or
canine teeth, largely developed, and the molars have sharp cutting
points. Those animals that feed on grass and grain, as the horse and
the sheep, have their molar teeth more rounded and flat on the crown.
The human teeth are adapted to feed on fruits, grain, or flesh, as
they are less pointed than those of the cat, and more pointed than
those of the sheep.
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216. Give the names of the permanent teeth. What teeth have but one
root, or "fang"? How many roots have the molars of the upper jaw? Of
the lower jaw? What is said of the shape of the teeth in different
species of animals?
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217. The teeth are composed principally of two substances--the
_i'vo-ry_ and the _en-am'el_. The internal part of the tooth or the
ivory, is harder and more enduring than bone, and forms the body of
the tooth. The enamel is remarkable for its hardness, and varies
somewhat in color with the age, temperament, habits, and manner of
living of different individuals. When any part of the enamel is
destroyed, it is never regenerated.
[Illustration: Fig. 56. A side view of the body and enamel of a front
tooth.]
[Illustration: Fig. 57. A side view of a molar tooth. 1, The enamel. 2,
The body of the tooth. 3, The cavity in the crown of the tooth that
contains the pulp. 4, A nerve that spreads in the pulp of the tooth. 5,
An artery that ramifies in the pulp of the tooth.]
218. Each tooth is divided into two parts, namely, _crown_ and _root_.
The crown is that part which protrudes from the jaw-bone and gum, and
is covered by the highly polished enamel. The root, or "fang," is
placed in the sockets of the jaw, and consists of bony matter. Through
this bony substance several small vessels pass, to aid in the growth
and also in the removal of the tooth. There are, beside these
vessels, small white cords passing to each tooth, called _nerves_.
(See fig. 57.) When these nerves are diseased, we have the toothache.
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217. Give the structure of the teeth. What is said of the enamel? 218.
Into how many parts are the teeth divided? Describe the crown. The
root. What vessels pass through the bony matter? What is their use?
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PHYSIOLOGY OF THE TEETH.
219. The use of the teeth is twofold. 1st. By the action of the
incisors the food is divided, while the molars grind or break down the
more solid portions of it. By these processes, the food is prepared to
pass more easily and rapidly into the stomach.
220. In the mastication of food there are two movements of the lower
jaw--the action by which the teeth are brought together, and the
lateral motion. In the former, the food is cut or divided, the jaws
acting like shears. This movement is produced by the action of two
large muscles situated on each side of the head and face.
_Observation._ The muscles attached to the lower jaw are of great
strength; by their action alone, some persons are enabled to bite the
hardest substances. By putting the fingers upon the side of the head
above and in front of the ears, and upon the face above the angle of
the jaw, while masticating food, the alternate swelling and relaxation
of these muscles will be clearly felt.
221. The lateral, or grinding movement of the teeth, is produced by
the action of a strong muscle that is attached to the lower jaw on the
inside.
_Observation._ Those animals that live solely on flesh, have only the
cutting, or shear-like movement of the jaws. Those that use
vegetables for food, have the grinding motion; while man has both the
cutting and grinding movement.
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219-222. _Give the physiology of the teeth._ 219. Give one of the
functions of the teeth. 220. How many movements of the lower jaw in
masticating food? What effect has the first movement upon the food?
How produced? What is the character of the masticating muscles? 221.
How is the grinding motion of the teeth produced? What is said of the
movements of the teeth in different animals?
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222. 2d. The teeth aid us in articulating with distinctness certain
letters and words. An individual who has lost his front teeth cannot
enunciate distinctly certain letters called dental. Again, as the
alveolar processes are removed by absorption soon after the removal of
the teeth, the lips and cheeks do not retain their former full
position, thus marring, in no slight degree, the symmetry of the lower
part of the face. Consequently, those simple observances that tend to
the preservation of the teeth are of great practical interest to all
persons.
HYGIENE OF THE TEETH.
223. _To preserve the teeth, they must be kept clean._ After eating
food, they should be cleansed with a brush and water, or rubbed with a
piece of soft flannel, to prevent the _tartar_ collecting, and to
remove the pieces of food that may have lodged between them.
Toothpicks may be useful in removing any particles inaccessible to the
brush. They may be made of bone, ivory, or the common goose-quill.
Metallic toothpicks should not be used, as they injure the enamel.
224. _The mouth should be cleansed with pure tepid water at night, as
well as in the morning_; after which the teeth should be brushed
upward and downward, both on the posterior and anterior surfaces. It
may be beneficial to use refined soap, once or twice every week, to
remove any corroding substance that may exist around the teeth; care
being taken to thoroughly rinse the mouth after its use.
225. _Food or drink should not be taken into the mouth when very hot
or very cold._ Sudden changes of temperature will crack the enamel,
and finally produce decayed teeth.
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222. What is another use of the teeth? 223-232. _Give the hygiene of
the teeth._ 223. How can the teeth be preserved? By what means? 224.
How often should they be cleansed? 225. What is said of very hot or
cold drinks?
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_Observation._ On this account, smoking is pernicious, because the
teeth are subjected to an alternate inhalation of both cold and warm
air.
226. _The temporary teeth should be removed as soon as they become
loose._ If a permanent tooth makes it appearance before the first is
removed, or has become loose, the milk tooth, although not loose,
should be removed without delay. This is necessary that the second set
of teeth may present a regular and beautiful appearance.
227. _In general, when the permanent teeth are irregular, one or more
should be removed._ If the teeth are crowded and irregular, in
consequence of the jaw being narrow and short, or when they press so
hard upon each other as to injure the enamel, remove one or more to
prevent their looking unsightly, and in a few months the remaining
teeth, with a little care, will fill the spaces.
_Observation._ When it is necessary to remove a tooth, apply to some
skilful operator. It requires as much skill and knowledge to extract
teeth _well_, as it does to amputate a limb; yet some persons, who
possess strong arms, will obtain a pair of forceps, or a tooth-key,
and hang out the sign of "surgeon-dentist," although ignorant of the
principles that should guide them.
228. _It is not always necessary to have teeth extracted when they
ache._ The nerve, or the investing membrane of the root, may be
diseased, and the tooth still be sound. In such instances, the tooth
should not be extracted, but the diseased condition may be remedied by
proper medication. There are many sound teeth, that become painful, as
already mentioned, which are unnecessarily removed.
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Why is smoking injurious to the teeth? 226. What remark respecting the
temporary teeth? 227. What remarks respecting the permanent teeth? Do
those persons that extract teeth require skill as well as knowledge?
228. Why should not teeth be extracted at all times when they are
painful?
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_Illustration._ Dr. H. M., of Belfast, Me., related to me that an
individual in that vicinity had his teeth, (all of them sound,) on one
side of the lower jaw, extracted by an ignoramus of a "tooth-puller,"
and this without any relief from pain. The disease was tic douloureux,
which was relieved by Dr. M.
229. _The preservation of the teeth requires that they be frequently
examined._ When a part of the enamel is removed, and a small portion
of the body of the tooth has become carious, in many instances such
teeth may be preserved from further decay by having them filled or
"plugged" with _gold foil_. All amalgams, pastes, and cheap patent
articles for filling, should be avoided, if you would preserve both
the teeth and the general health.
230. The practice of cracking nuts with the teeth, or of lifting heavy
bodies, and the constant habit of biting thread, should be avoided, as
they finally destroy the enamel.
231. _All acidulated drinks and mineral waters, that "set the teeth on
edge," are injurious._ All tooth-powders and washes that contain any
article that is acid, corrosive, or grinding, should be banished from
the toilet. Tobacco is not a preservative of the teeth. It contains
"grit," which wears away the enamel; beside, when chewed, it
debilitates the vessels of the gums, turns the teeth yellow, and
renders the breath and the appearance of the mouth disagreeable.
232. Healthy persons have generally sound teeth, while feeble persons
have decayed teeth. For this reason, we should try to learn and
practise the few simple rules that promote health.
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Give an illustration of the removal of sound teeth. 229. How may
decaying teeth be preserved? What should be avoided in the filling of
teeth? 230. What practices should also be avoided? 231. What is said
of acidulated drinks? What effect has the chewing of tobacco upon the
teeth? 232. What is one reason for preserving health?
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CHAPTER XIII.
THE DIGESTIVE ORGANS.
233. From the earliest existence of the human system to the last ray
of life, change is impressed upon it by the Giver of this curious
fabric. New atoms of matter are deposited, while the old and now
useless particles are constantly removed. The material necessary to
sustain the growth of the body in early life, and also to repair the
waste that is unceasing to animal existence, is the food we eat.
234. Food, animal or vegetable, contains most of the elements of the
different tissues of the system, yet it must undergo certain essential
alterations before it can become a part of the body. The first change
is effected by the action of the _Digestive Organs_.
ANATOMY OF THE DIGESTIVE ORGANS
235. The DIGESTIVE ORGANS are the _Mouth_, _Teeth_,[7] _Sal'i-va-ry
Glands_, _Phar'ynx_, _OE-soph'a-gus_, (gullet,) _Stom'ach_,
_In-tes'tines_, (bowels,) _Lac'te-als_, (milk, or chyle vessels,)
_Tho-rac'ic Duct_, _Liv'er_, and the _Pan'cre-as_, (sweetbread.)
[7] See Chapter XII.
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233. What is impressed upon the human system from its earliest
existence? What maintains this change? 234. Has animal or vegetable
food any resemblance to the different tissues of which it finally
forms a part? By what organs is the first change in the food effected?
235-258. _Give the anatomy of the digestive organs._ 235. Name them.
236. Describe the mouth.
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MOUTH is an irregular cavity, which contains the instruments of
mastication and the organs of taste. It is bounded in front by the
lips; on each side by the internal surface of the cheeks; above, by
the _hard palate_ (roof of the mouth) and teeth of the upper jaw;
below, by the tongue and teeth of the lower jaw; behind, it is
continuous with the pharynx, but is separated from it by a kind of
movable curtain, called the _soft palate_. This may be elevated or
depressed, so as to close the passage or leave it free.
237. The SALIVARY GLANDS are six in number; three on each side of the
jaw. They are called the _pa-rot'id_, the _sub-max'il-la-ry_ and the
_sub-lin'gual_.
[Illustration: Fig. 58. A view of the salivary glands in their proper
situations. 1, The parotid gland. 2, Its duct. 3, The submaxillary gland.
4, Its duct. 5, The sublingual gland, brought to view by the removal of a
section of the lower jaw.]
238. The PAROTID GLAND, the largest, is situated in front of the
external ear, and behind the angle of the jaw. A duct (Steno's) from
this gland opens into the mouth, opposite the second molar tooth of
the upper jaw.
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237. How many glands about the mouth? Give their names. What does fig.
58 represent? 238. Describe the parotid gland.
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239. The SUBMAXILLARY GLAND is situated within the lower jaw, anterior
to its angle. Its excretory duct (Wharton's) opens into the mouth by
the side of the _frae'num lin'guae_, (bridle of the tongue.)
240. The _SUBLINGUAL GLAND_ is elongated and flattened, and situated
beneath the mucous membrane of the floor of the mouth, on each side of
the fraenum linguae. It has seven or eight small ducts, which open into
the mouth by the side of the bridle of the tongue.
_Observation._ In the "mumps," the parotid gland is diseased. The
swelling under the tongue called the "frog" is a disease of the
sublingual gland.
[Illustration: Fig. 59. A side view of the face, oesophagus, and trachea.
1, The trachea (wind pipe.) 2, The larynx. 3, The oesophagus. 4, 4, 4,
The muscles of the upper portion of the oesophagus forming the pharynx.
5, The muscle of the cheek. 6, The muscle that surrounds, the mouth. 7,
The muscle that forms the floor of the mouth.]
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239. The submaxillary. 240. The sublingual. What observation
respecting these glands? What does fig. 59 represent?
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241. The PHARYNX is a membranous sac, situated upon the upper portion
of the spinal column. It extends from the base of the skull to the top
of the _tra'che-a_, (windpipe,) and is continuous with the oesophagus.
From the pharynx are four passages; one opens upward and forward to
the nose, the second leads forward to the mouth, the third downward to
the trachea and lungs, the fourth downward and backward to the
stomach.
242. The OESOPHAGUS is a large membranous tube that extends behind the
trachea, the heart, and lungs, pierces the diaphragm, and terminates
in the stomach. It is composed of two membranes--an internal, or
mucous, and a muscular coat. The latter is composed of two sets of
fibres; one extends lengthwise, the other is arranged in circular
bands.
243. The STOMACH is situated in the left side of the abdomen,
immediately below and in contact with the diaphragm. It has two
openings; one connected with the oesophagus, called the _car'di-ac_
orifice; the other connected with the upper portion of the small
intestine, called the _py-lor'ic_ orifice. It is composed of three
coats, or membranes. The exterior or serous coat is very tough and
strong, and invests every part of this important organ. The middle, or
muscular coat is composed of two layers of muscular fibres, one set of
which is arranged longitudinally, the other circularly. The interior
coat is called the mucous, and is arranged in _ru'gae_, (folds.) The
stomach is provided with a multitude of small glands, in which is
secreted the gastric fluid.
_Illustration._ The three coats of the stomach anatomically resemble
tripe, which is a preparation of the largest stomach of the cow or ox.
The outer coat is smooth and highly polished. The middle coat is
composed of minute threads, which are arranged in two layers. The
fibres of these layers cross each other. The inner coat is soft, and
presents many folds, usually named "the honey-comb."
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241. Describe the pharynx and the passages leading from it. 242. Give
the structure of the oesophagus. 243. Where is the stomach situated?
How many coats has it? Describe them. What article prepared for food
does the stomach resemble?
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[Illustration: Fig. 60. The inner surface of the stomach and duodenum. 1,
The lower portion of the oesophagus. 2, The opening through which the
food is passed into the stomach. 8, The stomach. 9, The opening through
which the food passes out of the stomach into the duodenum, or upper
portion of the small intestine. 10, 11, 14, The duodenum 12, 13, Ducts
through which the bile and pancreatic fluid pass into it. _a_, _b_, _c_,
The three coats of the stomach.]
244. The INTESTINES, or alimentary canal, are divided into two
parts--the _small_ and _large_. The small intestine is about
twenty-five feet in length, and is divided into three portions,
namely, the _Du-o-de'num_, the _Je-ju'num_, and the _Il'e-um_. The
large intestine is about five feet in length, and is divided into
three parts, namely, the _Cae'cum_, the _Co'lon_, and the _Rec'tum_.
(Appendix D.)
245. The DUODENUM is somewhat larger than the rest of the small
intestine, and has received its name from being in length about the
breadth of twelve fingers. It commences at the pylorus, and ascends
obliquely backward to the under surface of the liver. It then descends
perpendicularly in front of the right kidney, and passes transversely
across the lower portion of the spinal column, behind the colon, and
terminates in the jejunum. The ducts from the liver and pancreas open
into the perpendicular portion, about six inches from the stomach.
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244. Explain fig. 60. What is the length of the small intestine, and
how is it divided? What is the length of the large intestine? Give its
divisions. 245. Describe the duodenum.
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246. The JEJUNUM is continuous with the duodenum. It is thicker than
the rest of the small intestine, and has a pinkish tinge.
247. The ILEUM is smaller, and thinner in texture, and somewhat paler,
than the jejunum. There is no mark to distinguish the termination of
the one or the commencement of the other. The ileum terminates near
the right haunch-bone, by a valvular opening into the colon at an
obtuse angle. This arrangement prevents the passing of substances from
the colon into the ileum. The jejunum and ileum are surrounded above
and at the sides by the colon.
248. The small intestine, like the stomach, has three coats. The
inner, or mucous coat is thrown into folds, or valves. In consequence
of this valvular arrangement, the mucous membrane is more extensive
than the other tissues, and gives a greater extent of surface with
which the aliment comes in contact. There are imbedded under this
membrane an immense number of minute glands, and it has a great number
of piles, like those upon velvet. For this reason, this membrane is
sometimes called the _vil'lous_ coat.
249. The CAECUM is the blind pouch, or cul-de-sac, at the commencement
of the large intestine. Attached to its extremity is the _ap-pend'ix
verm-i-form'is_, (a long, worm-shaped tube.) It is from one to six
inches in length, and of the size of a goose-quill.
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What important ducts open into it? 246. Describe the jejunum. 247. The
ileum. 248. What is said of the coats of the intestines? Why is the
mucous membrane sometimes called the villous coat? 249. Describe the
caecum.
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250. The COLON is divided into three parts--the _ascending_,
_transverse_, and _descending_. The ascending colon passes upward from
the right haunch-bone to the under surface of the liver. It then bends
inward, and crosses the upper part of the abdomen, below the liver and
stomach, to the left side under the name of the transverse colon. At
the left side, it turns, and descends to the left haunch-bone, and is
called the descending colon. Here it makes a peculiar curve upon
itself, which is called the _sig'moid flex'ure_.
[Illustration: Fig. 61. 1, 1, The duodenum. 2, 2, The small intestine. 3,
The junction of the small intestine with the colon. 4, The appendix
vermiformis. 5, The caecum. 6, The ascending colon. 7, The transverse
colon. 8, The descending colon. 9, The sigmoid flexure of the colon. 10,
The rectum.]
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250. Describe the course of the divisions of the colon. Explain fig.
61.
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251. The RECTUM is the termination of the large intestine. The large
intestine has three coats, like the stomach and small intestine. The
longitudinal fibres of the muscular coat are collected into three
bands. These bands are nearly one half shorter than the intestine, and
give it a sacculated appearance, which is characteristic of the caecum
and colon.
252. The LACTEALS are minute vessels, which commence in the villi,
upon the mucous surface of the small intestine. From the intestine
they pass between the membranes of the _mes'en-ter-y_ to small glands,
which they enter. The first range of glands collects many small
vessels, and transmits a few larger branches to a second range of
glands; and, finally, after passing through several successive ranges
of these glandular bodies, the lacteals, diminished in number and
increased in size, proceed to the enlarged portion of the thoracic
duct, into which they open. They are most numerous in the upper
portion of the small intestine.
253. The THORACIC DUCT commences in the abdomen, by a considerable
dilatation, which is situated in front of the lower portion of the
spinal column. From this point, it passes through the diaphragm, and
ascends to the lower part of the neck. In its ascent, it lies anterior
to the spine, and by the side of the aorta and oesophagus. At the
lower part of the neck, it makes a sudden turn downward and forward,
and terminates by opening into a large vein which passes to the heart.
The thoracic duct is equal in diameter to a goose-quill, and, at its
termination, is provided with a pair of semilunar valves, which
prevent the admission of venous blood into its cylinder.
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251. What is said of the arrangement of the fibres of the muscular
coat of the large intestine? 252. What are the lacteals? Give their
course from the mucous coat of the intestine to the thoracic duct.
253. Describe the course of the thoracic duct. How is the venous blood
prevented from passing into this duct?
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[Illustration: Fig. 62. A portion of the small intestine, lacteal
vessels, mesenteric glands, and thoracic duct. 1, The intestine. 2, 3, 4,
Mesenteric glands, through which the lacteals pass to the thoracic duct.
5, 6, The thoracic duct. 7, The point in the neck where it turns down to
enter the vein at 8. 9, 10, The aorta. 11, 12, Vessels of the neck. 13,
14, 15, The large veins that convey the blood and chyle to the heart. 16,
17, The spinal column. 18, The diaphragm, (midriff.)]
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Explain fig. 62. What is said respecting the mesenteric glands?
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_Observation._ The mesenteric glands, which are situated between two
layers of serous membrane (mesentery) that connects the small
intestine with the spinal column, occasionally become diseased in
childhood, and prevent the chyle from passing to the thoracic duct.
Children thus affected have a voracious appetite, and at the same time
are becoming more and more emaciated. The disease is called mesenteric
consumption.
254. The LIVER, a gland appended to the alimentary canal, is the
largest organ in the system, and weighs about four pounds. It is
situated in the right side, below the diaphragm, and is composed of
several lobes. Its upper surface is convex; its under, concave. This
organ is retained in its place by several ligaments. It performs the
double office of separating impurities from the venous blood, and of
secreting a fluid (bile) necessary to chylification. On the under
surface of the liver is a membranous sac, called the _gall-cyst_,
which is generally considered as a reservoir for the bile.
[Illustration: Fig. 63. The under surface of the liver. 1, The right
lobe. 2, The left. 3, 4, Smaller lobes. 10, The gall-bladder, or cyst,
lodged in its depression. 17, The notch on the posterior border, for the
spinal column.]
_Observation._ A good idea of the liver and intestines can be obtained
by examining these parts of a pig. In this animal, the sacs, or
pouches, of the large intestine are well defined.
255. The PANCREAS is a long, flattened gland, analogous to the
salivary glands. It is about six inches in length, weighs three or
four ounces, and is situated transversely across the posterior wall of
the abdomen, behind the stomach. A duct from this organ opens into the
duodenum.
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254. Describe the liver. 255. What is said of the pancreas?
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256. The SPLEEN, (milt,) so called because the ancients supposed it to
be the seat of melancholy, is an oblong, flattened organ, situated in
the left side, in contact with the diaphragm, stomach, and the
pancreas. It is of a dark, bluish color, and is abundantly supplied
with blood, but has no duct which serves as an outlet for any
secretion. Its use is not well determined.
[Illustration: Fig. 64. The pancreas with its duct, through which the
pancreatic secretion passes into the duodenum.]
257. The OMENTUM (caul) consists of four layers of the serous
membrane, which descends from the stomach and transverse colon. A
quantity of adipose matter is deposited around its vessels, which
ramify through its structure. Its function is twofold in the animal
economy. 1st. It protects the intestines from cold. 2d. It facilitates
the movements of the intestines upon each other during their
vermicular, or worm-like action.
258. Every part of the digestive apparatus is supplied with arteries,
veins, lymphatics, and nervous filaments, from the ganglionic system
of nerves.
-=-=-=-=-=-=-=-=-=-=-=-=
256. Why is the spleen so called? What is peculiar to this organ? 257.
Of what is the omentum composed? What is its use? 258. With what is
every part of the digestive apparatus supplied?
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CHAPTER XIV.
PHYSIOLOGY OF THE DIGESTIVE ORGANS.
259. Substances received into the stomach as food, must necessarily
undergo many changes before they are fitted to form part of the animal
body. The solid portions are reduced to a fluid state, and those parts
that will nourish the body are separated from the waste material.
260. The first preparation of food for admission into the system,
consists in its proper mastication. The lips in front, the cheeks upon
the side, the soft palate, by closing down upon the base of the
tongue, retain the food in the mouth, while it is subjected to the;
process of _mas-ti-ca'tion_, (chewing.) The tongue rolls the mass
around, and keeps it between the teeth, while they divide the food to
a fineness suitable for the stomach.
261. While the food is in process of mastication, there is incorporated
with it a considerable amount of _sa-li'va_, (spittle.) This fluid is
furnished by the salivary glands, situated in the vicinity of the
mouth. The saliva moistens and softens the food, so that, when carried
into the pharynx. it is passed, with ease, through the oesophagus into the
stomach.
262. When the food has been properly masticated, (and in rapid eaters
when it is not,) the soft palate is raised from the base of the tongue
backward, so as to close the posterior opening through the nostrils.
By a movement of the muscles of the tongue, cheeks, and floor of the
mouth, simultaneous with that of the soft palate, the food is pressed
into the upper part of the pharynx.
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259-272. _Give the physiology of the digestive organs._ 259. What is
necessary before food can nourish the body? 260. Describe how
mastication is performed. 261. Of what use is the saliva in the
process of mastication? 262. How is the food pressed into the
pharynx?
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263. When in the pharynx, the food and drink are prevented from
passing into the trachea by a simple valve-like arrangement, called
the _ep-i-glot'tis_. The ordinary position of this little organ is
perpendicular, so as not to obstruct the passage of air into the
lungs; but in the act of swallowing, it is brought directly over the
opening of the trachea, called the _glot'tis_. The food, being forced
backward, passes rapidly over the epiglottis into the oesophagus,
where the circular band of muscular fibres above, contracts and forces
the food to the next lower band. Each band relaxes and contracts
successively, and thus presses the alimentary ball downward and onward
to the stomach.[8]
[8] The process of deglutition may be comprehended by analyzing the
operation of swallowing food or saliva.
_Observation._ If air is inhaled when the food or drink is passing
over the glottis, some portions of it may be carried into the larynx
or trachea. This produces violent spasmodic coughing, and most
generally occurs when an attempt is made to speak while masticating
food; therefore, never talk when the mouth contains food.
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263. When the food is in the pharynx, how is it prevented from passing
into the trachea, or windpipe? Describe how it is passed into the
stomach? Give the observation. 264. Describe how the food in the
stomach is converted into chyme.
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264. When the food reaches the stomach, the gastric glands are excited
to action, and they secrete a powerful solvent, called gastric juice.
The presence of food in the stomach also increases a contractile
action of the muscular coat, by which the position of the food is
changed from one part of this cavity to another. Thus the aliment is
brought in contact with the mucous membrane, and each portion of it
becomes saturated with gastric juice, by which it is softened, or
dissolved into a pulpy homogeneous mass, of a creamy consistence,
called _Chyme_. The food is not all converted into chyme at the same
time; but as fast as it is changed, it passes through the pyloric
orifice into the duodenum.
_Observation._ The gastric juice has the property of coagulating
liquid albuminous matter when mixed with it. It is this property of
rennet, which is an infusion of the fourth stomach of the calf, by
which milk is coagulated, or formed into "curd."
265. The CHYME is conveyed through the pyloric orifice of the stomach
into the duodenum. The chyme not only excites an action in the
duodenum, but also in the liver and pancreas. _Mucus_ is then secreted
by the duodenum, _bile_ by the liver, and _pancreatic fluid_ by the
pancreas. The bile and pancreatic fluid are conveyed into the
duodenum, and mixed with the chyme. By the action of these different
fluids, the chyme is converted into a fluid of a whitish color, called
_Chyle_, and into residuum.
_Observation._ The bile has no agency in the change through which
the food passes in the stomach. In a healthy condition of this
organ, no bile is found in it. The common belief, that the stomach
has a redundancy of this secretion, is erroneous. If bile is ejected
in vomiting, it merely shows, not only that the action of the
stomach is inverted, but also that of the duodenum. A powerful
emetic will, in this way, generally bring this fluid from the most
healthy stomach. A knowledge of this fact might save many a stomach
from the evils of emetics, administered on false impressions of
their necessity, and continued from the corroboration of these by
the appearance of bile, till derangement, and perhaps permanent
disease, are the consequences.
266. The CHYLE and residual matter are moved over the mucous surface
of the small intestine, by the action of its muscular coat. As the
chyle is carried along the tract of the intestine, it comes in contact
with the villi, where the lacteal vessels commence. These imbibe, or
take up, the chyle, and transfer it through the mesenteric glands into
the thoracic duct, through which it is conveyed into a large vein at
the lower part of the neck. In this vein the chyle is mixed with the
venous fluid. The residual matter is conveyed into the large
intestine, through which it is carried and excreted from the system.
(Appendix E.)
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What peculiar property has gastric juice? 265. Where and how is chyme
converted into chyle? What is said in regard to the bile? 266. What
becomes of the chyle? Of the residuum?
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267. In the process of digestion, the food is subjected to five
different changes. 1st. The chewing and admixture of the saliva with
the food; this process is called _mastication_.
268. 2d. The change through which the food passes in the stomach by
its muscular contraction, and the secretion from the gastric glands;
this is called _chymification_.
269. 3d. The conversion of the homogeneous chyme, by the agency of the
bile and pancreatic secretions, into a fluid of milk-like appearance;
this is _chylification_.
270. 4th. The absorption of the chyle by the lacteals, and its
transfer through them and the thoracic duct, into the subclavian vein
at the lower part of the neck.[9]
[9] The chyle is changed by the lacteals and mesenteric glands, but
the nature of this change is not, as yet, well defined or
understood.
271. 5th. The separation and excretion of the residuum.
272. Perfection of the second process of digestion requires thorough
and slow mastication. The formation of proper chyle demands
appropriate mastication and chymification; while a healthy action of
the lacteals requires that all the anterior stages of the digestive
process be as perfect as possible. (Appendix F.)
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267. Recapitulate the five changes in the digestive process.
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_Note._ Let the pupil review the anatomy and physiology of the
digestive organs from figs. 62 and 65, or from anatomical outline
plate No. 5.
[Illustration: Fig. 65. An ideal view of the organs of digestion, opened
nearly the whole length. 1, The upper jaw. 2, The lower jaw. 3, The
tongue. 4, The roof of the mouth. 5, The oesophagus. 6, The trachea. 7,
The parotid gland. 8, The sublingual gland. 9, The stomach. 10, 10, The
liver. 11, The gall-cyst. 12, The duct that conveys the bile to the
duodenum, (13, 13.) 14, The pancreas. 15, 15, 15, 15, The small
intestine. 16, The opening of the small intestine into the large
intestine. 17, 18, 19, 20, The large intestine. 21, The spleen. 22, The
upper part of the spinal column.]
CHAPTER XV.
HYGIENE OF THE DIGESTIVE ORGANS.
273. It is a law of the system, that each organ is excited to healthy
and efficient action, when influenced by its appropriate stimulus.
Accordingly, nutrient food, that is adapted to the wants of the
system, imparts a healthy stimulation to the salivary glands during
the process of mastication. The food that is well masticated, and has
blended with it a proper amount of saliva, will induce a healthy
action in the stomach. Well-prepared chyme is the natural stimulus of
the duodenum, liver, and pancreas; pure chyle is the appropriate
excitant of the lacteal vessels.
274. The perfection of the digestive process, as well as the health of
the general system, requires the observance of certain conditions.
These will be considered under four heads:--1st. The _Quantity_ of
food that should be taken. 2d. Its _Quality_. 3d. The _Manner_ in
which it should be taken. 4th. The _Condition_ of the system when food
is taken.
275. The QUANTITY of food necessary for the system varies. Age,
occupation, temperament, temperature, habits, amount of clothing,
health and disease are among the circumstances which produce the
variation.
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273-330. _Give the hygiene of the digestive organs._ 273. Give a law
of the system. What is the appropriate stimulus of the salivary glands
during mastication? Of the stomach? Of the duodenum? Of the lacteal
vessels? 274. What does the perfection of the digestive organs
require? 275. What exert an influence on the quantity of food
necessary for the system?
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276. _The child and youth require food to promote the growth of the
different parts of the body._ The more rapid the growth of the child,
the greater the demand for food. This accounts for the keen appetite
and vigorous digestion in childhood. When the youth has attained his
full growth, this necessity for nutriment ceases; after this period of
life, if the same amount of food is taken, and there is no increase of
labor or exertion, the digestive apparatus will become diseased, and
the vigor of the whole system diminished.
_Observation._ When the body has become emaciated from want of
nutriment, either from famine or disease, there is an increased demand
for food. This may be gratified with impunity until the individual has
regained the usual size, but repletion should be avoided.
277. _Food is required to repair the waste, or loss of substance
that attends action._ In every department of nature, waste, or loss of
substance, attends and follows action. When an individual increases
his exercise,--changes from light to severe labor,--or the inactive
and sedentary undertake journeys for pleasure, the fluids of the
system circulate with increased energy. The old and exhausted
particles of matter are more rapidly removed through the action of
the vessels of the skin, lungs, kidneys, and other organs, and
their places are filled with new atoms, deposited by the small
blood-vessels.
278. As the chyle supplies the blood with the newly vitalized
particles of matter, there is, consequently, an increased demand for
food. This want of the system induces, in general, a sensation of
hunger or appetite, which may be regarded as an indication of the
general state of the body. The sympathy that exists throughout the
system accords to the stomach the power of making known this state to
the nervous system, and, if the functions of this faithful monitor
have not been impaired by disease, abuse, or habit, the call is
imperious, and should be regarded.
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276. At what age is the appetite keen and the digestion vigorous? Why?
What is said in regard to the quantity of food when the youth has
attained his growth? What exception, as given in the observation? 277.
Give another demand for food. What effect has increased exercise upon
the system? 278. How are the new particles of matter supplied? What
does this induce?
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279. _When exercise or labor is lessened, the quantity of food should
be diminished._ When a person who has been accustomed to active
exercise, or even hard manual labor, suddenly changes to an employment
that demands less activity, the waste attendant on action will be
diminished in a corresponding degree; hence the quantity of food
should be lessened in nearly the same proportion as the amount of
exercise is diminished. If this principle be disregarded, the tone of
the digestive organs will be impaired, and the health of the system
enfeebled.
280. This remark is applicable to those students who have left
laborious employments to attend school. Although the health is firm,
and the appetite keen from habit, yet every pupil should practise some
self-denial, and not eat as much as the appetite craves, the first
week of the session. After some days, the real wants of the system
will generally be manifested by a corresponding sensation of hunger.
_Observation._ It is a common observation that in academies and
colleges, the older students from the country, who have been
accustomed to hard manual labor, suffer more frequently from defective
digestion and impaired health than the younger and feebler students
from the larger towns and cities.
281. _Food is essential in maintaining a proper temperature of the
system._ The heat of the system, at least in part, is produced in the
minute vessels of the several organs, by the union of oxygen with
carbon and hydrogen, which the food and drink contain. The amount of
heat generated, is greatest when it is most rapidly removed from the
system, which occurs in cold weather. This is the cause of the system
requiring more food in winter than summer.
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279. Why should the quantity of food be diminished when the exercise
is lessened? What effect if this principle be disregarded? 280. To
what class is this remark applicable? What is often observed among
students in academies and colleges? 281. State another demand for
food. What is one source of heat in the body?
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_Observation._ Persons that do not have food sufficient for the
natural wants of the system, require more clothing than those who are
well fed.
282. The last-mentioned principle plainly indicates the propriety and
necessity of lessening the quantity of food as the warm season
approaches. Were this practised, the tone of the stomach and the vigor
of the system would continue unimpaired, the "season complaints" would
be avoided, and the "strengthening bitters" would not be sought to
create an appetite.
_Observation._ Stable-keepers and herdsmen are aware of the fact, that
as the warm season commences, then animals require less food. Instinct
teaches these animals more truly, in this particular, than man allows
reason to guide him.
283. _The quantity of food should have reference to the present
condition of the digestive organs._ If they are weakened or diseased,
so that but a small quantity of food can be properly digested or
changed, that amount only should be taken. Food does not invigorate
the system, except it is changed, as has been described in previous
paragraphs.
_Observation._ When taking care of a sick child, the anxiety of the
mother and the sufferings of the child may induce her to give food
when it would be highly injurious. The attending physician is the only
proper person to direct what quantity should be given.
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Why do we eat more in the winter than in the summer? What practical
observation is given? 282. Why should the quantity of food be lessened
as warm weather commences? What would be avoided if this principle
were obeyed? 283. Why should the present condition of the digestive
organs be regarded in reference to the quantity of food? Mention an
instance in which it would be injudicious to give food.
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284. _The quantity of food is modified, in some degree, by habit._ A
healthy person, whose exercise is in pure air, may be accustomed to
take more food than is necessary. The useless excess is removed from
the system by the waste outlets, as the skin, lungs, liver, kidneys,
&c. In such cases, if food is not taken in the usual quantity, there
will be a feeling of emptiness, if not of hunger, from the want of the
usual distention of the stomach. This condition of the digestive
organs may be the result of disease, but it is more frequently
produced by inordinate daily indulgence in eating, amounting almost to
gluttony.
285. _Large quantities of food oppress the stomach, and cause general
languor of the whole body._ This is produced by the extra demands made
on the system for an increased supply of blood and nervous fluid to
enable the stomach to free itself of its burden. Thus, when we intend
to make any extraordinary effort, mental or physical, at least for one
meal, we should eat less food than usual, rather than a greater
quantity.
286. _No more food should be eaten than is barely sufficient to
satisfy the appetite._ Nor should appetite be confounded with taste.
The one is a natural desire for food to supply the wants of the
system; the other is an artificial desire merely to gratify the
palate.
287. Although many things may aid us in determining the quantity of
food proper for an individual, yet there is no certain guide in all
cases. It is maintained by some, that the sensation of hunger or
appetite is always an indication of the want of food, while the
absence of this peculiar sensation is regarded as conclusive evidence
that aliment is not demanded. This assertion is not correct, as an
appetite may be created for food by condiments and gormandizing, which
is as artificial and as morbid as that which craves tobacco or ardent
spirits. On the other hand, a structural or functional disease of the
brain may prevent that organ from taking cognizance of the sensations
of the stomach, when the system actually requires nourishment.
Observation shows, that disease, habit, the state of the mind, and
other circumstances, exert an influence on the appetite.
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284. Show the effect of habit upon the quantity of food that is eaten.
What is said in regard to inordinate eating? 285. What is the effect
of eating large quantities of food? What suggestion when an
extraordinary effort, either mental or physical, is to be made? 286.
How much food should generally be eaten? 287. What is the assertion of
some persons relative to the quantity of food necessary for the
system?
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_Observation._ Dr. Beaumont noticed, in the experiments upon Alexis
St. Martin, that after a certain amount of food was converted into
chyme, the gastric juice ceased to ooze from the coats of the stomach.
Consequently, it has been inferred by some writers on physiology, that
the glands which supply the gastric fluid, by a species of instinctive
intelligence, would only secrete enough fluid to convert into chyme
the aliment needed to supply the real wants of the system. What are
the reasons for this inference? There is no evidence that the gastric
glands possess instinctive intelligence, and can there be a reason
adduced, why they may not be stimulated to extra functional action as
well as other organs, and why they may not also be influenced by
habit?
288. While all agree that the remote or predisposing cause of hunger
is, usually, a demand of the system for nutrient material, the
proximate or immediate cause of the sensation of hunger is not clearly
understood. Some physiologists suppose that it is produced by an
engorged condition of the glands of the stomach which supply the
gastric juice; while others maintain that it depends on a peculiar
condition of the nervous system.
289. The QUALITY of the food best adapted to the wants of the system
is modified by many circumstances. There are many varieties of food,
and these are much modified by the different methods of preparation.
The same kind of food is not equally well adapted to different
individuals, or to the same individual in all conditions; as vocation,
health, exposure, habits of life, season, climate, &c., influence the
condition of the system.
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What does observation show? 288. What is said of the causes of
hunger? 289. Why is not the same kind of food adapted to different
individuals?
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290. All articles of food may be considered in two relations: 1st, As
nutritive. 2d, As digestible. Substances are nutritious in proportion
to their capacity to yield the elements of chyle, of which carbon,
oxygen, hydrogen, and nitrogen are the most essential; they are
digestible in proportion to the facility with which they are acted
upon by the gastric juice. These properties should not be confounded
in the various articles used for food.
291. As a "living body has no power of forming elements, or of
converting one elementary substance into another, it therefore follows
that the elements of which the body of an animal is composed must be
in the food." (Chap. III.) Of the essential constituents of the human
body, carbon, hydrogen, oxygen, and nitrogen are the most important,
because they compose the principal part of the animal body; while the
other elements are found in very small proportions, and many of them
only in a few organs of the system. (Appendix G.)
_Observation._ Nitrogen renders food more stimulating, particularly if
combined with a large quantity of carbon, as beef. Those articles that
contain the greatest amount of the constituent elements of the system
are most nutritious. As milk and eggs contain all the essential
elements of the human system, so they are adapted to almost universal
use, and are highly nutritious.
-=-=-=-=-=-=-=-=-=-=-=-=
290. In what proportion are substances nutritious? Digestible? Why
does beef stimulate the system? What is said of milk and eggs?
-=-=-=-=-=-=-=-=-=-=-=-=
292. The following table, by Pereira, in his treatise on Food and
Diet may aid the student in approximating to correct conclusions of
the quantity of nutriment in different kinds of food, and its
adaptation to the wants of the system.
TABLE,
SHOWING THE AVERAGE QUANTITY OF DRY, OR SOLID MATTER, CARBON,
NITROGEN, AND MOISTURE, IN DIFFERENT ARTICLES OF DIET.
-------------------+---------+---------+-----------+------------
One hundred Parts. | Dry | Carbon. | Nitrogen. | Water
| Matter. | | |
-------------------+---------+---------+-----------+------------
Arrowroot, | 81.8 | 36.4 | | 18.2
Beans, | 85.89 | 38.24 | | 14.11
Beef, fresh, | 25 | 12.957 | 3.752 | 75
Bread, rye, | 67.79 | 30.674 | | 32.21
Butter, | 100 | 65.6 | |
Cabbage, | 7.7 | | 0.28 | 92.3
Carrot, | 12.4 | | 0.30 | 87.6
Cherries, | 25.15 | | | 74.85
Chickens, | 22.7 | | | 77.3
Codfish, | 20 | | | 80
Cucumbers, | 2.86 | | | 97.14
Eggs, whites, | 20 | | | 80
----, yolk, | 46.23 | | | 53.77
Lard, hog's, | 100 | 79.098 | |
Milk, cow's, | 12.98 | | | 87.02
Oats, | 79.2 | 40.154 | 1.742 | 20.8
Oatmeal, | 93.4 | | | 6.6
Olive-oil, | 100 | 77.50 | |
Oysters, | 12.6 | | | 87.4
Peaches, | 19.76 | | | 80.24
Pears, | 16.12 | | | 83.88
Peas, | 84 | 35.743 | | 16
Plums, greengage, | 28.90 | | | 71.10
Potatoes, | 24.1 | 10.604 | 0.3615 | 75.9
Rye, | 83.4 | 38.530 | 1.417 | 16.6
Suet, mutton, | 100 | 78.996 | |
Starch, potato, | 82 | 36.44 | | 18
----, wheat, | 85.2 | 37.5 | | 14.8
Sugar, maple, | | 42.1 | |
----, refined, | | 42.5 | |
----, brown, | | 40.88 | |
Turnips, | 7.5 | 3.2175 | 0.1275 | 92.5
Veal, roasted, | | 52.52 | 14.70 |
Wheat, | 85.5 | 39.415 | 1.966 | 14.5
-------------------+---------+---------+-----------+------------
_Note._ Let the pupil mention those articles of food that are
most nutritious, from a review of this table, and the last four
paragraphs.
293. Those articles that do not contain the essential elements of the
system should not be used as exclusive articles of diet. This
principle has been, and may be illustrated by experiment. Feed a dog
with pure sugar, or olive-oil, (articles that contain no nitrogen,)
for several weeks, and the evil effects of non-nitrogenous nutriment
will be manifested. At first, the dog will take his food with avidity,
and seem to thrive upon it; soon this desire for food will diminish,
his body emaciate, his eye become ulcerated, and in a few weeks he
will die; but mix bran or sawdust with the sugar or oil, and the
health and vigor of the animal will be maintained for months. A
similar phenomenon will be manifested, if grain only be given to a
horse, without hay, straw, or material of like character. (Appendix
H.)
294. Some articles of food contain the elements of chyle in great
abundance, yet afford but little nutriment, because they are difficult
of digestion; while other articles contain but a small quantity of
these elements, and afford more nourishment, because they are more
easily affected by the digestive process.
-=-=-=-=-=-=-=-=-=-=-=-=
293. How has the effect of non-nitrogenous nutriment been illustrated?
294. Why do some articles of food that contain the elements of chyle
afford but little nutriment? Why do articles that contain a small
quantity of these elements afford more nourishment? 295. How was the
time required for digesting different articles of food ascertained?
-=-=-=-=-=-=-=-=-=-=-=-=
295. The following table exhibits the general results of experiments
made on Alexis St. Martin, by Dr. Beaumont, when he endeavored to
ascertain the time required for the digestion of different articles of
food.[10] The stomach of St. Martin was ruptured by the bursting of a
gun. When he recovered from the effects of the accident under the
surgical care of Dr. Beaumont, the stomach became adherent to the
side, with an external aperture. Nature had formed a kind of valve,
which closed the aperture from the interior, and thus prevented the
contents of the stomach from escaping; but on pushing it aside, the
process of digestion could be seen. Through this opening, the
appearance of the coats of the stomach and food, at different stages
of digestion, were examined.
[10] The time required for the digestion of the different articles of
food might vary in other persons; and would probably vary in
the same individual at different periods, as the employment,
health, season, &c., exert a modifying influence.
TABLE,
SHOWING THE MEAN TIME OF DIGESTION OF THE DIFFERENT
ARTICLES OF DIET.
-----------------------------+--------------+--------
Articles. | Preparation. | Time
| | h. m.
-----------------------------+--------------+--------
Apples, sour, hard, | Raw, | 2 50
Apples, sour, mellow, | Raw, | 2
Apples, sweet, do., | Raw, | 1 30
Bass, striped, fresh, | Broiled, | 3
Beans, pod, | Boiled, | 2 30
Beef, fresh, lean, rare, | Roasted, | 3
Beef, fresh, lean, dry, | Roasted, | 3 30
Beef steak, | Broiled, | 3
Beef, with salt only, | Boiled, | 3 36
Beef, with mustard, | Boiled, | 3 10
Beef, fresh, lean, | Fried, | 4
Beef, old, hard, salted, | Boiled, | 4 15
Beets, | Boiled, | 3 45
Bread, wheat, fresh, | Baked, | 3 30
Bread, corn, | Baked, | 3 15
Butter, | Melted, | 3 30
Cabbage head, | Raw, | 2 30
Cabbage, with vinegar, | Raw, | 2
Cabbage, | Boiled, | 4 30
Cake, sponge, | Baked, | 2 30
Carrot, orange, | Boiled, | 3 15
Catfish, | Fried, | 3 30
Cheese, old, strong, | Raw, | 3 30
Chicken, full-grown, | Fricas'd, | 2 45
Codfish, cured, dry, | Boiled, | 2
Corn, green, & beans, | Boiled, | 3 45
Corn bread, | Baked, | 3 15
Corn cake, | Baked, | 3
Custard, | Baked, | 2 45
Dumpling, apple, | Boiled, | 3
Ducks, domesticated, | Roasted, | 4
Ducks, wild, | Roasted, | 4 30
Eggs, fresh, | Boiled hard, | 3 30
Eggs, fresh, | Boiled soft, | 3
Eggs, fresh, | Fried, | 3 30
Eggs, fresh, | Raw, | 2
Flounder, fresh, | Fried, | 3 30
Fowl, domestic, | Boiled, | 4
Fowl, domestic, | Roasted, | 4
Goose, | Roasted, | 2 30
Lamb, fresh, | Broiled, | 2 30
Liver, beef's, fresh, | Broiled, | 2
Meat hashed with vegetables, | Warm'd, | 2 30
Milk, | Boiled, | 2
Milk, | Raw, | 2 15
Mutton, fresh, | Roasted, | 3 15
Mutton, fresh, | Broiled, | 3
Mutton, fresh, | Boiled, | 3
Oysters, fresh, | Raw, | 2 55
Oysters, fresh, | Roasted, | 3 15
Oysters, fresh, | Stewed, | 3 30
Parsnips, | Boiled, | 2 30
Pig, sucking, | Roasted, | 2 30
Pigs' feet, soused, | Boiled, | 1
Pork, fat and lean, | Roasted, | 5 15
Pork, recently salted, | Boiled, | 4 30
Pork, recently salted, | Fried, | 4 15
Pork, recently salted, | Broiled, | 3 15
Pork, recently salted, | Raw, | 3
Pork, steak, | Broiled, | 3 15
Potatoes, Irish, | Boiled, | 3 30
Potatoes, Irish, | Baked, | 2 30
Rice, | Boiled, | 1
Sago, | Boiled, | 1 45
Salmon, salted, | Boiled, | 4
Sausage, fresh, | Broiled, | 3 20
Soup, beef, vegetables, and | Boiled, | 4
bread, | |
Soup, chicken, | Boiled, | 3
Soup, mutton, | Boiled, | 3 30
Soup, oyster, | Boiled, | 3 30
Suet, beef, fresh, | Boiled, | 5 30
Suet, mutton, | Boiled, | 4 30
Tapioca, | Boiled, | 2
Tripe, soused, | Boiled, | 1
Trout, salmon, fresh, | Boiled, | 1 30
Trout, salmon, fresh, | Fried, | 1 30
Turkey, domesticated, | Roasted, | 2 30
Turkey, | Boiled, | 2 25
Turkey, wild, | Roasted, | 2 18
Turnips, flat, | Boiled, | 3 30
Veal, fresh, | Broiled, | 4
Veal, fresh, | Fried, | 4 30
Venison steak, | Broiled, | 1 35
-----------------------------+--------------+--------
296. In view of this table, the question may be suggested, Is that
article of food most appropriate to the system which is most easily
and speedily digested? To this it may be replied, that the stomach is
subject to the same law as the muscles and other organs; exercise,
within certain limits, strengthens it. If, therefore, we always eat
those articles most easily digested, the digestive powers will be
weakened; if over-worked, they will be exhausted. Hence the kind and
amount of food should be adapted to the maintenance of the digestive
powers, and to their gradual invigoration when debilitated.
_Observation._ Food that is most easily digested is not always most
appropriate to a person convalescing from disease. If the substance
passes rapidly through the digestive process, it may induce a
recurrence of the disease. Thus the simple preparations which are not
stimulating, as water-gruel, are better for a sick person than the
more digestible beef and fish.
297. The question is not well settled, whether animal or vegetable
food is best adapted to nourish man. There are nations, particularly
in the torrid zone, that subsist, exclusively, on vegetables; while
those of the frigid zone feed on fish or animal food. In the temperate
zone, among civilized nations, a mixed diet is almost universal. When
we consider the organization of the human system, the form and
arrangement of the teeth, the structure of the stomach and intestines,
we are led to conclude, that both animal and vegetable food is
requisite, and that a mixed diet is most conducive to strength,
health, and long life.
-=-=-=-=-=-=-=-=-=-=-=-=
296. How is the question answered, whether that article is most
appropriate to the system which is most easily digested? Give
observation. 297. What is said of the adaptation of animal and
vegetable food to man?
-=-=-=-=-=-=-=-=-=-=-=-=
298. _The food should be adapted to the distensible character of the
stomach and alimentary canal._ The former will be full, if it contain
only a gill; it may be so distended as to contain a quart. The same is
true of the intestines. If the food is concentrated, or contains the
quantity of nutriment which the system requires, in small bulk, the
stomach and intestines will need the stimulation of distention and
friction, which is consequent upon the introduction and transit of the
innutritious material into and through the alimentary canal. If the
food is deficient in innutritious matter, the tendency is, to produce
an inactive and diseased condition of the digestive organs. For this
reason, nutrient food should have blended with it innutritious
material. Unbolted wheat bread is more healthy than hot flour cakes;
ripe fruits and vegetables than rich pies, or jellies.
_Observation._ 1st. The observance of this rule is of more importance
to students, sedentary mechanics, and those individuals whose
digestive apparatus has been enfeebled, than to those of active habits
and firm health.
2d. The circumstance that different articles of food contain different
proportions of waste, or innutritious matter, may be made practically
subservient in the following way: If, at any particular season of the
year, there is a tendency to a diarrhoea, an article that contains a
small proportion of waste should be selected for food; but, if there
is a tendency to an inactive or costive condition of the intestinal
canal, such kinds of food should be used as contain the greatest
proportion of waste, as such articles are most stimulating to the
digestive organs, and, consequently, most laxative.
299. _In the selection of food, the influence of season and climate
should be considered._ Food of a highly stimulating character may be
used almost with impunity during the cold weather of a cold climate;
but in the warm season, and in a warm climate, it would be very
deleterious. Animal food, being more stimulating than vegetable, can
be eaten in the winter but vegetable food should be used more freely
in the spring and summer.
-=-=-=-=-=-=-=-=-=-=-=-=
298. What is said of the distensible character of the stomach and
alimentary canal? What is the effect of eating highly concentrated
food? Why is the unbolted wheat bread more healthy than flour cakes?
Give observation 1st. Observation 2d. 299. What kind of food is
adapted to cold weather? To warm weather?
-=-=-=-=-=-=-=-=-=-=-=-=
300. _The influence of food on the system is modified by the age of
the individual._ The organs of a child are more sensitive and
excitable than those of a person advanced in years. Therefore a
vegetable diet would be most appropriate for a child, while
stimulating animal food might be conducive to the health of a person
advanced in life.
_Observation._ When the digestive organs are highly impressible or
diseased, it is very important to adopt a nutritious, unstimulating,
vegetable diet, as soon as the warm season commences.
301. _Habit is another strong modifying influence._ If a person has
been accustomed to an animal or vegetable diet, and there is a sudden
change from one to the other, a diseased condition of the system,
particularly of the digestive apparatus, usually follows. When it is
necessary to change our manner of living, it should be done
gradually.[11]
[11] The system is gradually developed, and all changes of food,
apparel, labor, exercise, or position, should be gradual. Even
a change from a bad to a good habit, on this principle, should
be gradual.
302. _Some temperaments require more stimulating food than others._ As
a general rule, those persons whose sensations are comparatively
obtuse, and movements slow, will be benefited by animal food; while
those individuals whose constitutions are highly impressible, and
whose movements are quick and hurried, require a nutritious and
unstimulating vegetable diet.
-=-=-=-=-=-=-=-=-=-=-=-=
300. What kinds of food are appropriate to old age? Why? What kinds to
childhood? Why? 301. What is the effect when there is a sudden change
from a vegetable to an animal diet? How should all changes of the
system be made? 302. Do different temperaments require different kinds
of food? What general rule is given?
-=-=-=-=-=-=-=-=-=-=-=-=
CHAPTER XVI.
HYGIENE OF THE DIGESTIVE ORGANS, CONTINUED.
303. The MANNER in which food should be taken is of much practical
importance; upon it the health of the digestive organs measurably
depends. But few circumstances modify the proper manner of taking
food, or should exercise any controlling influence.
304. _Food should be taken at regular periods._ The interval between
meals should be regulated by the character of the food, the age,
health, exercise, and habits of the individual. The digestive process
is more energetic and rapid in the young, active, and vigorous, than
in the aged, indolent, and feeble; consequently, food should be taken
more frequently by the former than by the latter class.
305. In some young and vigorous persons, food may be digested in one
hour; in other persons, it may require four hours or more. The average
time, however, to digest an ordinary meal, will be from two to four
hours. In all instances, the stomach will require from one to three
hours to recruit its exhausted powers after the labor of digesting a
meal before it will again enter upon the vigorous performance of its
duties.
306. _Food should not be taken too frequently._ If food is taken
before the stomach has regained its tone and energy by repose, the
secretion of the gastric juice, and the contraction of the muscular
fibres, will be imperfect. Again, if food is taken before the
digestion of the preceding meal has been completed, the effects will
be still worse, because the food partially digested becomes mixed with
that last taken. Therefore the interval between each meal should be
long enough for the whole quantity to be digested, and the time of
repose should be sufficient to recruit the exhausted organs. The
feebler the person and the more debilitated the stomach, the more
important to observe the above directions.
-=-=-=-=-=-=-=-=-=-=-=-=
303. Why is it important that we regard the manner of taking our food?
304. How should the intervals between meals be regulated? 305. What is
the average time required to digest an ordinary meal? 306. Why should
not food be taken too frequently?
-=-=-=-=-=-=-=-=-=-=-=-=
_Observation._ In the feeding of infants, as well as in supplying food
to older children, the preceding suggestions should always be
regarded. The person who has been confined by an exhausting sickness,
should most scrupulously regard this rule, if he wishes to regain his
strength and flesh with rapidity. As the rapidity of the digestive
process is less in students and individuals who are engaged in
sedentary employments, than in stirring agriculturists, the former
class are more liable to take food too frequently than the latter,
while its observance is of greater importance to the sedentary artisan
than to the lively lad and active farmer.
307. _Food should be well masticated._ All solid aliments should be
reduced to a state of comparative fineness, by the teeth, before it is
swallowed; the gastric fluid of the stomach will then blend with it
more readily, and act more vigorously in reducing it to chyme. The
practice of swallowing solid food, slightly masticated, or "bolting"
it down, tends to derange the digestive process and impair the
nutrition of the system.
308. _Mastication should be moderate, not rapid._ In masticating food,
the salivary glands are excited to action, and some time must elapse
before they can, secrete saliva in sufficient quantities to moisten
it. If the aliment is not supplied with saliva, digestion is retarded;
besides, in rapid eating, more food is generally consumed than the
system demands, or can be easily digested. Laborers, as well as men of
leisure, should have ample time for taking their meals. Imperfect
mastication is a prevailing cause of indigestion.
-=-=-=-=-=-=-=-=-=-=-=-=
What persons would be benefited by observing the preceding remarks?
307. Why should food be well masticated? What is the effect of
"bolting down" food? 308. How should mastication be performed? Why?
-=-=-=-=-=-=-=-=-=-=-=-=
309. _Food should be masticated and swallowed without drink._ As the
salivary glands supply fluid to moisten the dry food, the use of tea,
coffee, water, or any other fluid, is not demanded by nature's laws
while taking a meal. One objection to "washing down" the food with
drink is, the aliment is moistened, not with the saliva, but with the
drink. This tends to induce disease, not only in the salivary organs,
by leaving them in a state of comparative inactivity, but in the
stomach, by the deficiency of the salivary stimulus. Another is, large
quantities of fluids, used as drinks, give undue distention to the
stomach, and lessen the energy of the gastric juice by its dilution,
thus retarding digestion. Again, drinks taken into the stomach must be
removed by absorption before the digestion of other articles is
commenced.
_Observation._ Were it customary not to place drinks on the table
until the solid food is eaten, the evil arising from drinking too much
at meals would be obviated. The horse is never known to leave his
provender, nor the ox his blade of grass, to wash it down; but many
persons, from habit rather than thirst, drink largely during meals.
310. The peculiar sensation in the mouth and fauces, called thirst,
may not always arise from the demand for fluids to increase the
_serum_ (water) of the blood, as in the desire for drink attendant on
free perspiration, for then, pure water or some diluent drink is
absolutely necessary; but it may be the result of fever, or local
disease of the parts connected with the throat. In many instances,
thirst may be allayed by chewing some hard substance, as a dry
cracker. This excites a secretion from the salivary glands, which
removes the disagreeable sensation. In thirst, attendant on a heated
condition of the system, this practice affords relief, and is safe;
while the practice of drinking large quantities of cold fluids, is
unsafe, and should never be indulged.
-=-=-=-=-=-=-=-=-=-=-=-=
Why should all persons have ample time for eating? 309. Why are drinks
not necessary while masticating food? Give the objections to "washing
down" food. What observation relative to drink? 310. Does the
sensation of thirst always arise from a real want of the system?
-=-=-=-=-=-=-=-=-=-=-=-=
311. _Food or drink should not be taken when very hot._ When food or
drink is taken hot, the vessels of the mucous membrane of the gums,
mouth, and stomach are unduly stimulated for a short time; and this is
followed by reaction, attended by a loss of tone, and debility of
these parts. This practice is a fruitful cause of spongy gums, decayed
teeth, sore mouth, and indigestion.
312. _Food or drink should not be taken very cold._ If a considerable
quantity of very cold food or liquid be taken immediately into the
stomach, the health will be endangered, and the tone of the system
will be impaired, from the sudden abstraction of heat from the coats
of the stomach, and from surrounding organs, to impart warmth to the
cold food or drink. This arrests the digestive process, and the food
is retained in the stomach too long, and causes oppression and
irritation. Consequently, food and drink that are moderately heated
are best adapted to the natural condition of the digestive apparatus.
_Observation._ Food of an injurious quality, or taken in an improper
manner, affects the inferior animals as well as man. The teeth of cows
that are closely penned in cities, and are fed on distillery slops, or
the unhealthy slops and remnants of kitchens, decay and fall out in
about two years. Can the milk of such diseased animals be healthy--the
proper nourishment for children?
-=-=-=-=-=-=-=-=-=-=-=-=
Give instances when it does and when it does not. 311. Why should not
food or drink be taken hot? 312. Why should they not be taken cold?
Show some of the effects of improper food upon the inferior animals.
-=-=-=-=-=-=-=-=-=-=-=-=
313. The CONDITION of the system should be regarded when food is
taken. This is necessary, as the present and ulterior condition of the
digestive apparatus is strongly influenced by the state of the other
organs of the system.
314. _Food should not be taken immediately after severe exertion,
either of the body or mind._ For all organs in action require and
receive more blood and nervous fluid, than when at rest. This is true
of the brain, muscles, and vocal organs, when they have been actively
exercised. The increased amount of fluid, both sanguineous and
nervous, supplied to any organ during extra functional action, is
abstracted from other parts of the system. This enfeebles and
prostrates the parts that supply the blood and nervous fluid to the
active organ. Again, when any organ has been in vigorous action for a
few hours, some time will elapse before the increased action of the
arteries and nerves abates, and a due supply of fluids is transmitted
to other organs, or an equilibrium of action in the system is
reestablished.
315. Thus food should not be taken immediately after severe mental
labor, protracted speaking, continued singing, or laborious manual
toil; as the digestive organs will be in a state of comparative
debility, and consequently unfit to digest food. From thirty to sixty
minutes should elapse, after the cessation of severe employment,
before food is taken. This time may be spent in cheerful amusement or
social conversation.
_Observation._ The practice of students and accountants going
immediately from severe mental labor to their meals, is a pernicious
one, and a fruitful cause of indigestion and mental debility. The
custom of farmers and mechanics hurrying from their toil to the
dinner-table, does much to cause dyspepsia and debility among these
classes in community.
-=-=-=-=-=-=-=-=-=-=-=-=
313. Should the condition of the system be regarded in taking food?
314. When should food not be taken? Why? What is the result when an
organ has been in vigorous action? 315. After the cessation of severe
toil, how much time should expire before eating? What is one cause of
indigestion among students and accountants?
-=-=-=-=-=-=-=-=-=-=-=-=
316. _Severe mental or manual toil should not be entered upon
immediately after eating._ As there is an increased amount of blood
and nervous fluid supplied to the stomach and alimentary canal during
the digestion of food, a deficiency exists in other organs. This is
evinced by a slight paleness of the skin, and a disinclination to
active thought and exercise. Under such circumstances, if either the
mind, vocal organs, or muscles are called into energetic action, there
will be an abstraction of the necessary amount of blood and nervous
fluid from the stomach, and the process of digestion will be arrested.
This will not only cause disease of the digestive organs, but chyle
will not be formed, to nourish the system.
_Illustration._ An English gentleman fed two dogs upon similar
articles of food. He permitted one to remain quiet in a dark room; the
other he sent in pursuit of game. At the expiration of one hour, he
had both killed. The stomach of the dog that had remained quiet was
nearly empty. The food had been properly changed and carried forward
into the alimentary canal. In the stomach of the dog that had used his
muscles in chasing game, the aliment remained nearly unaltered.
317. The same principle may be applied to the action of the organs of
man. If his mind or muscles act intensely soon after eating, the
stomach will not be sufficiently stimulated by blood and nervous fluid
to change the food in a suitable period. The Spanish practice of
having a "siesta," or sleep after dinner, is far better than the
custom of the Anglo-Saxon race, who hurry from their meals to the
field, shop, or study, in order to save time, which, in too many
instances, is lost by a sense of oppression and suffering which soon
follows.
-=-=-=-=-=-=-=-=-=-=-=-=
316. Why should not severe manual or mental exertion be made
immediately after eating? State the illustration. 317. May this
principle be applied to the action of the human stomach? What is said
of the Spanish custom of resting after dinner?
-=-=-=-=-=-=-=-=-=-=-=-=
318. In some instances of good health, the infringement of this
organic law may seem to pass with impunity, but Nature, though
lenient, sooner or later asserts her claims. The practice of the
Spaniard may be improved by indulging, for an hour before resuming
toil, in moderate exercise of the muscular system, conjoined with
agreeable conversation and a hearty laugh, as this facilitates
digestion, and tends to "shake the cobwebs from the brain."
_Observation._ No judicious teamster drives his animals as soon as
they have swallowed their food, but gives them a period for repose, so
that their food may be digested, and their systems invigorated. In
this way, he secures the greatest amount of labor from his team.
319. _The mind exerts an influence upon the digestive process._ This
is clearly exhibited, when an individual receives intelligence of the
loss of a friend or of property. He may at the time be sitting before
a plentiful board, with a keen appetite; but the unexpected news
destroys it, because the excited brain withholds its stimulus. This
shows the propriety of avoiding absorbing topics of thought at meals,
as labored discussions and matters of business; but substitute
cheerful and light conversation, enlivening wit, humor, the social
intercourse of family and friends; these keep the brain in action, but
not in toil. Under such circumstances, the blood and nervous fluid
flow freely, the work of digestion is readily commenced, and easily
carried on.
320. _Indigestion arising from a prostration of the nervous system,
should be treated with great care._ The food should be simple,
nutritious, moderate in quantity, and taken at regular periods. Large
quantities of stimulating food, frequently taken, serve to increase
the nervous prostration. Those afflicted should exercise in the open
air, and engage in social conversation, that the brain may be excited
to a natural or healthy action, in order that it may impart to the
digestive organs the necessary stimulation.
-=-=-=-=-=-=-=-=-=-=-=-=
Of the Anglo-Saxon race? 318. How can the Spanish custom be improved?
319. How is the influence of the mind on the digestive process
exhibited? What does it show the necessity of avoiding? 320. How
should indigestion arising from nervous prostration be treated?
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321. _Persons should abstain from eating, at least three hours before
retiring for sleep._ It is no unusual occurrence, for those persons
who have eaten heartily immediately before retiring to sleep, to have
unpleasant dreams, or to be aroused from their unquiet slumber by
colic pains. In such instances, the brain becomes partially dormant,
and does not impart to the digestive organs the requisite amount of
nervous influence. The nervous stimulus being deficient, the unchanged
food remains in the stomach, causing irritation of this organ.
_Illustration._ A healthy farmer, who was in the habit of eating one
fourth of a mince pie immediately before going to bed, became annoyed
with unpleasant dreams, and, among the varied images of his fancy, he
saw that of his deceased father. Becoming alarmed, he consulted a
physician, who, after a patient hearing of the case, gravely advised
him to eat _half_ of a mince pie, assuring him that he would then see
his grandfather.
322. _When the general system and digestive organs are enfeebled,
mild, unstimulating food, in small quantities, should be given._ In
the instance of a shipwrecked and famished mariner, or a patient
recovering from disease, but a small quantity of nourishment should be
given at a time. The reason for this, is, that when the stomach is
weakened from want of nourishment, it is as unfitted for a long period
of action in digesting food, as the muscles are, under like
circumstances, for walking. Consequently, knowledge and prudence
should direct the administration of food under these circumstances.
The popular adage, that "food never does harm when there is a desire
for it," is untrue, and, if practically adopted, may be injurious and
destructive to life.
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321. What is the effect of eating immediately before retiring for
sleep? How is this illustrated in the case of a healthy farmer? 322.
How should the food be given when both the digestive organs and
general system are debilitated? Give the reason.
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_Observation._ Liquids are rapidly removed from the stomach by
absorption. Hence, in cases of great prostration, when it is desirable
to introduce nutriment into the system, without delay, the animal and
vegetable broths are a desirable and convenient form of supplying
aliment.
323. _The condition of the skin exercises an important influence on
the digestive apparatus._ Let free perspiration be checked, either
from uncleanliness or from chills, and it will diminish the functional
action of the stomach and its associated organs. This is one of the
fruitful causes of the "liver and stomach complaints" among the
half-clothed and filthy population of the crowded cities and villages
of our country. Attention to clothing and bathing would likewise
prevent many of the diseases of the alimentary canal, called "season
complaints," particularly among children.
324. _Restricting the movements of the ribs and diaphragm impairs
digestion._ At each full inspiration, the ribs are elevated, and the
central portion of the diaphragm is depressed, from one to two inches.
This depression is accompanied by a relaxation of the anterior
abdominal walls. At each act of expiration, the relaxed abdominal
muscles contract, the ribs are depressed, the diaphragm relaxes, and
its central parts ascend. These movements of the midriff cause the
elevation and depression of the stomach, liver, and other abdominal
organs, which is a natural stimulus of these parts.
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In cases of great prostration, what is recommended? 323. How is the
influence that the skin exercises on the digestive organs illustrated?
324. What effect on the digestive process has the restriction of the
ribs and diaphragm?
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325. It is noted of individuals who restrain the free movements of the
abdominal muscles by tight dresses, that the tone and vigor of the
digestive organs are diminished. The restricted waist will not admit
of a full and deep inspiration and so essential is this to health,
that abuse in this respect soon enfeebles and destroys the functions
of the system.
326. _Pure air is necessary to give a keen appetite and vigorous
digestion._ The digestive organs not only need the stimulus of blood,
but they absolutely need the influence of pure blood, which cannot
exist in the system, except when we breathe a pure air. From this we
learn why those persons who sleep in small, ill ventilated rooms, have
little or no appetite in the morning, and why the mouth and throat are
so dry and disagreeable. The effect of impure blood, in diminishing
the desire for food, and enfeebling the digestive organs, is well
illustrated by the following incidents.
_Illustrations._ 1st. Dr. Reid, in his work on "Ventilation of Rooms,"
relates that an innkeeper in London, when he provided a public dinner,
always spread his tables in an under-ground room, with low walls,
where the air was confined and impure. He assigned as a reason for so
doing, that his guests consumed only one third as much food and wine,
as if the tables were laid in the open air.
2d. A manufacturer stated before a committee of the British
Parliament, that he had removed an arrangement for ventilating his
mill, because he noticed that his men ate much more after his mill was
ventilated, than previous to admitting fresh air into the rooms, and
that he could not _afford_ to have them breathe pure air.
_Observation._ Many of the cases of indigestion among clergymen,
seamstresses, school teachers, sedentary mechanics, and factory
operatives, are produced by breathing the impure air of the rooms they
occupy. These cases can be prevented, as well as cured, by proper
attention to ventilation.
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325. What is observed of those individuals that restrict the movements
of the abdominal muscles? 326. Why is pure air necessary to vigorous
digestion? Give illustration 1st. Illustration 2d. What is one cause
of indigestion among the sedentary class in community?
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327. _The position of a person, in standing or sitting, exerts an
influence upon the digestive organs._ If a person lean, or stoop
forward, the distance between the pelvic bones and the diaphragm is
diminished. This prevents the depression of the diaphragm, while the
stomach, liver, pancreas, and other abdominal organs, suffer
compression, which induces many severe diseases of these organs. As
healthy and well-developed muscles keep the spinal column in an erect
position, which conduces to the health of the organs of digestion, the
child should be taught to avoid all positions _but the erect_, while
studying or walking. This position, combined with unrestricted waists,
will do much to remove the now prevalent disease, dyspepsia.
328. _Whatever kind of aliment is taken, it is separated into
nutriment and residuum_; the former of which is conveyed, through the
medium of the circulation, to all organs of the system, and the
latter, if not expelled, accumulates, causing headache and dizziness,
with a general uneasiness; and, if allowed to continue, it lays the
foundation of a long period of suffering and disease. For the
preservation of health, it is necessary that there should be a daily
evacuation of the residual matter.
_Observation._ In chronic diseases of the digestive organs, very
frequently, there is an inactive, or costive condition of the
alimentary canal. This may be removed in many cases, and relieved in
all instances, by friction over the abdominal organs, and by making an
effort at some stated period each day, (evening is best,) to evacuate
the residuum. In acute diseases, as fever, regard should be given to
regularity in relieving the intestines of residuum. Attention to this
suggestion will in many instances obviate the necessity of cathartic
medicine.
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327. Why does the position of a person affect digestion? 328. Into
what are different kinds of aliment separated?
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329. We would add, for the benefit of those afflicted with hemorrhoids,
or piles, that the best time for evacuating the intestinal canal
would be immediately before retiring for the night. During the
night, while recumbent, the protruding parts return to their proper
place, and the surrounding organs acquire increased tone to retain them.
The same observance will do much to prevent such prostrating
diseases.[12]
[12] The urinary organs, as well as the intestinal canal, should be
frequently and regularly evacuated. Some most distressing and
frequently incurable complaints are caused by false customs and
false delicacy in this particular. Teachers should be
particularly careful, and regard this suggestion in reference
to young pupils.
330. To recapitulate: digestion is most perfect when the action of the
cutaneous vessels is energetic; the brain and vocal organs moderately
stimulated by animated conversation; the blood well purified; the
muscular system duly exercised; the food of an appropriate quality,
taken in proper quantities, at regular periods, and also properly
masticated.
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330. Give the summary when digestion is most perfect.
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CHAPTER VXII.
THE CIRCULATORY ORGANS.
331. The ultimate object of the food and drink introduced into the
body, is to furnish material to promote the growth and repair the
waste of the organs of the system. The formation of chyle (the
nutrient portion of the food) has been traced through the digestive
process, and its transfer into the vein at the lower part of the neck,
from which it is conveyed to the heart; and, finally, in the lungs it
assimilates to the character of blood.
332. The BLOOD, after standing a short time, when drawn from its
vessels, separates into _se'rum_, (a watery fluid,) and _co-ag'u-lum_,
(clot.) This fluid is distributed to every part of the system. There
is no part so minute that it does not receive blood. The organs by
which this distribution is effected are so connected that there is
properly neither beginning nor end; but as it respects their
functions, they are connected in a complete circle. From this
circumstance, they are called the _Circulatory Organs_.
ANATOMY OF THE CIRCULATORY ORGANS.
333. The CIRCULATORY ORGANS are the _Heart_, _Ar'te-ries_, _Veins_,
and _Cap'il-la-ries_.
334. The HEART is placed obliquely, in the left cavity of the chest,
between the right and left lung. Its general form is that of an
inverted cone, the base of which is directed upward and backward,
toward the right shoulder, while its apex points forward to the left
side, about three inches from the sternum to the space between the
fifth and sixth ribs. Its under side rests upon the tendinous portion
of the diaphragm. The heart is surrounded by a sac, called the
_per-i-car'di-um_, (heart-case.) The interior surface of this membrane
secretes a watery fluid, that lubricates the exterior of the heart,
and obviates friction between it and the pericardium.
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331. what is the ultimate object of the food? 332. Of what is the
blood composed? What is said of the distribution of the blood? 333.
Name the circulatory organs. 334-351. _Give the anatomy of the
circulatory organs._ 334. Describe the heart.
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[Illustration: Fig. 66. A front view of the heart. 1, The right auricle
of the heart. 2, The left auricle. 3, The right ventricle. 4, The left
ventricle. 5, 6, 7, 8, 9, 10, The vessels[13] through which the blood
passes to and from the heart.]
[Illustration: Fig. 67. A back view of the heart. 1, The right auricle.
2, The left auricle. 3, The right ventricle. 4, The left ventricle. 5, 6,
7, The vessels that carry the blood to and from the heart. 9, 10, 11, The
nutrient vessels of the heart.]
[13] All vessels that carry blood to the heart, are called _veins_.
All vessels that carry blood _from_ the heart, are called
_arteries_.
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With what is it surrounded? What is its use? How much fluid does this
membrane contain when healthy?
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_Observation._ In health, there is usually about a tea-spoonful of
fluid in the pericardium. When these parts are diseased, it may be
thrown out more abundantly, and sometimes amounts to several ounces,
producing a disease called dropsy of the heart. But all the unpleasant
sensations in the region of the heart are not caused by an increased
amount of fluid in the pericardium, as this disease is not of frequent
occurrence.
335. The heart is composed of muscular fibres, that traverse it in
different directions, some longitudinally, but most of them in a
spiral direction. The human heart is a double organ, or it has two
sides, called the right and the left. The compartments of the two
sides are separated by a muscular _sep'tum_, or partition. Again, each
side of the heart is divided into two parts, called the _Au'ri-cle_
(deaf ear) and the _Ven'tri-cle_.
[Illustration: Fig. 68. A section of the heart, showing its cavities and
valves. 3, The right auricle. 4, The opening between the right auricle
and right ventricle. 5, The right ventricle. 6, The tricuspid valves. 7,
The pulmonary artery. 9, The semilunar valves of the pulmonary artery.
10, The septum between the right and left ventricle. 12, The left
auricle. 13, The opening between the left auricle and left ventricle. 14,
The left ventricle. 15, The mitral valves. 16, The aorta. 17, The
semilunar valves of the aorta.]
336. The AURICLES differ in muscularity from the ventricles. Their
walls are thinner, and of a bluish color. These cavities are a kind of
reservoir, designed to contain the blood arriving by the veins.
337. The VENTRICLES not only have their walls thicker than the
auricles, but they differ in their internal structure. From the
interior of these cavities arise fleshy columns, called _co-lum'nae
car'ne-ae_. The walls of the left ventricle are thicker and stronger
than those of the right.
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335. Of what is the heart composed? Give its divisions. 336. Describe
the auricles. 337. Describe the ventricles.
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338. The cavities in the right side of the heart are triangular in
shape; those of the left, oval. Each cavity will contain about two
ounces of blood. Between the auricle and ventricle in the right side
of the heart, there are three folds, or doublings, of thin, triangular
membrane, called the _tri-cus'pid_ valves. Between the auricle and
ventricle in the left side, there are two valves, called the
_mi'tral_. There are seen passing from the floating edge of these
valves to the columnae carneae, small white cords, called _chor'dae
ten'di-nae_, which prevent the floating edge of the valve from being
carried into the auricle.
339. The right ventricle of the heart gives rise to the _Pul'mo-na-ry_
artery; the left ventricle, to a large artery called the _A-ort'a_. At
the commencement of each of these arteries there are three folds of
membrane, and from their shape, they are called _sem-i-lu'nar_
valves.
340. The heart is supplied with arteries and veins, which ramify
between its muscular fibres, through which its _nutrient_ blood
passes. It has, likewise, a few lymphatics, and many small nervous
filaments from the sympathetic system of nerves. This organ, in its
natural state, exhibits but slight indications of sensibility, and
although nearly destitute of the sensation of touch, it is yet,
however, instantly affected by every painful bodily excitement, or
strong mental emotions.
_Observation._ To obtain a clear idea of the heart and its valves, it
is recommended to examine this part of an ox or calf. In order that
each ventricle be opened without mutilating the fleshy columns,
tendinous cords, and valves, cut on each side of the septum parallel
to it. This may be easily found between the ventricles, as they differ
in thickness.
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338. How do the cavities in the heart differ? What is found between
the auricle and ventricle in the right side of the heart? How many
valves in the left side, and their names? Where are the tendinous
cords, and what is their use? 339. What vessels proceed from the
ventricles? What is said of their valves? 340. With what is the heart
supplied? What is said of its sensibility? How can an idea of the
structure of the heart be obtained?
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341. The ARTERIES are the cylindrical tubes that convey the blood from
the heart to every part of the system. They are dense in structure,
and preserve, for the most part, the cylindrical form, when emptied of
their blood, which is their condition after death.
342. The arteries are composed of three coats. The external, or
cellular coat, is firm and strong; the middle, or fibrous coat, is
composed of yellowish fibres. This coat is elastic, fragile, and
thicker than the external coat. Its elasticity enables the vessel to
accommodate itself to the quantity of blood it may contain. The
internal coat is a thin, serous membrane, which lines the interior of
the artery, and gives it the smooth polish which that surface
presents. It is continuous with the lining membrane of the heart.
343. Communications between arteries are free and numerous. They
increase in frequency with diminution in the size of the branches, so
that through the medium of the minute ramifications, the entire body
may be considered as one circle of inosculation. The arteries, in
their distribution through the body, are enclosed in a loose, cellular
investment, called a sheath, which separates them from the surrounding
tissues.
344. The PULMONARY ARTERY commences in front of the origin of the
aorta. It ascends obliquely to the under surface of the arch of the
aorta, where it divides into two branches, one of which passes to the
right, the other to the left lung. These divide and subdivide in the
structure of the lungs, and terminate in the capillary vessels, which
form a net-work around the air-cells, and become continuous with the
minute branches of the pulmonary veins. This artery conveys the impure
blood to the lungs, and, with its corresponding veins, establishes the
_lesser_, or _pulmonic circulation_.
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341. What are arteries? 342. Give their structure. 343. What is said
of the communications between the arteries? In their distribution, how
are they separated from the surrounding tissues? 344. Describe the
pulmonary artery.
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[Illustration: The divisions of this artery continue to divide and
subdivide, until they become no larger than hairs in size. These minute
vessels pass over the air-cells, represented by small dark points around
the margin of the lungs.]
345. The AORTA proceeds from the left ventricle of the heart, and
contains the pure, or nutrient blood. This trunk gives off branches,
which divide and subdivide to their ultimate ramifications,
constituting the great arterial tree which pervades, by its minute
subdivisions, every part of the animal frame. This great artery and
its divisions, with their returning veins, constitute the _greater_,
or _systemic circulation_.
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What does this artery and its corresponding veins establish? Explain
fig. 69. 345. Describe the aorta. What do this artery and its
corresponding veins constitute?
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[Illustration: Fig. 70. The aorta and its branches. 1, The commencement
of the aorta. 2, The arch of the aorta. 3, The carotid artery. 4, The
temporal artery. 5, The subclavian artery. 6, The axillary artery. 7, The
brachial artery. 8, The radial artery. 9, The ulnar artery. 10, The iliac
artery. 11, The femoral artery. 12, The tibial artery, 13. The peroneal
artery.]
346. The VEINS are the vessels which return the blood to the auricles
of the heart, after it has been circulated by the arteries through
the various tissues of the body. They are thinner and more delicate in
structure than the arteries, so that when emptied of their blood, they
become flattened and collapsed. The veins commence by minute radicles
in the capillaries, which are every where distributed through the
textures of the body, and coalesce to constitute larger and larger
branches, till they terminate in the large trunks which convey the
dark-colored blood directly to the heart. In diameter they are much
larger than the arteries, and, like those vessels, their combined area
would constitute an imaginary cone, the apex of which is placed at the
heart, and the base at the surface of the body.
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What does fig. 70 represent? 346. What are the veins?
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347. The communications between the veins are more frequent than
between the arteries, and take place between the larger as well as
among the smaller vessels. The office of these inosculations is very
apparent, as tending to obviate the obstructions to which the veins
are peculiarly liable, from the thinness of their coats, and from
inability to overcome great impediments by the force of their current.
These tubes, as well as the arteries, are supplied with nutrient
vessels, and it is to be presumed that nervous filaments from the
sympathetic nerves are distributed to their coats.
348. The external, or cellular coat of the veins, is dense and firm,
resembling the cellular tunic of the arteries. The middle coat is
fibrous, like that of the arteries, but extremely thin. The internal
coat is serous, and also similar to that of the arteries. It is
continuous with the lining membrane of the heart at one extremity, and
with the lining membrane of the capillaries at the other.
349. At certain intervals, the internal coat forms folds, or
duplicatures, which constitute valves. They are generally composed of
two semilunar folds, one on each side of the vessel. The free
extremity of the valvular folds is concave, and directed forward, so
that while the current of blood sets toward the heart, they present no
impediment to its free passage; but let the current become retrograde,
and it is impeded by their distention. The valves are most numerous in
the veins of the extremities, particularly the deeper veins situated
between the muscles; but in some of the larger trunks, and also in
some of the smaller veins, no valves exist.
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Where do they commence? 347. What is said of their communications?
What is the apparent design of the inosculations of the veins? What
vessels are distributed to the coats of the veins? 348. Give the
structure of the coats of the veins. 349. How are the valves in the
veins formed?
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[Illustration: Fig. 71. A vein laid open to show the valves. 1, The trunk
of the vein. 2, 2, Its valves. 3, An opening of a branch into the main
trunk.]
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What is their use? Where are they the most numerous?
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350. The CAPILLARIES constitute a microscopic net-work, and are so
distributed through every part of the body as to render it impossible
to introduce the smallest needle beneath the skin, without wounding
several of these fine vessels. They are remarkable for the uniformity
of diameter, and for the constant divisions and communications which
take place between them.
351. The capillaries inosculate, on the one hand, with the terminal
extremity of the arteries, and on the other, with the commencement of
the veins. They establish the communication between the termination of
the arteries and the beginning of the veins. The important operations
of secretion and the conversion of the nutrient materials of the blood
into bone, muscle, &c., are performed in these vessels.
[Illustration: Fig. 72. An ideal view of a portion of the pulmonic
circulation. 1, 1, A branch of the artery that carries the impure blood
to the lungs. 3, 3, Capillary vessels. 2, 2, A vein through which red
blood is returned to the left side of the heart.]
[Illustration: Fig. 73. An ideal view of a portion of the systemic
circulation. 1, 1, A branch of the aorta. This terminates in the
capillaries, (3, 3.) 2, 2, A vein through which the impure blood is
carried to the right side of the heart.]
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350. What do the capillaries constitute? For what are they remarkable?
351. What relation do they bear to the arteries and veins? What
important operations are performed in these vessels? What is
represented by fig. 72? By fig. 73?
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