son, and young persons often find themselves cursed with a terrible
disease known as alcoholism--a keen, morbid appetite for liquor that
demands gratification at any cost--stamped upon their very being through
the reckless indulgence of this habit on the part of some one of their
ancestors. [Footnote: The American Medical Association, at their meeting
in St. Paul, Minnesota (1883), restated in a series of resolutions their
conviction, that "alcohol should be classed with other powerful drugs;
that when prescribed medically, it should be done with conscientious
caution and a sense of great responsibility; that used as a beverage it is
productive of a large amount of physical and mental disease; that it
_entails diseased and enfeebled constitutions upon offspring_, and
that it is the cause of a large percentage of the crime and pauperism of
our large cities and country."]
THE LAW OF HEREDITY is, in this connection, well worth consideration. "The
world is beginning to perceive," says Francis Galton, "that the life of
each individual is, in some real sense, a continuation of the lives of his
ancestors." "Each of us is the footing up of a double column of figures
that goes back to the first pair." "We are omnibuses," remarks Holmes, "in
which all our ancestors ride." We inherit from our parents our features,
our physical vigor, our mental faculties, and even much of our moral
character. Often, when one generation is skipped, the qualities will
reappear in the following one. The virtues, as well as the vices, of our
forefathers, have added to, or subtracted from, the strength of our brain
and muscle. The evil tendencies of our natures, which it is the struggle
of our lives to resist, constitute a part of our heirlooms from the past.
Our descendants, in turn, will have reason to bless us only if we hand
down to them a pure healthy physical, mental, and moral being.
"There is a marked tendency in nature to transmit all diseased conditions.
Thus, the children of consumptive parents are apt to be consumptives. But
of all agents, alcohol is the most potent in establishing a heredity that
exhibits itself in the destruction of mind and body. [Footnote: Nearly all
the diseases springing from indulgence in distilled and fermented liquors
are liable to become hereditary, and to descend to at least three or four
generations, unless starved out by uncompromising abstinence. But the
distressing aspect of the heredity of alcohol is the transmitted drink-
crave. This is no dream of an enthusiast, but the result of a natural law.
Men and women upon whom this dread inheritance has been forced are
everywhere around us, bravely struggling to lead a sober life.--DR.
NORMAN KERR.] Its malign influence was observed by the ancients long
before the production of whiskey or brandy, or other distilled liquors,
and when fermented liquors or wines only were known. Aristotle says,
'Drunken women have children like unto themselves,' and Plutarch remarks,
'One drunkard is the father of another.' The drunkard by inheritance is a
more helpless slave than his progenitor, and his children are more
helpless still, unless on the mother's side there is an untainted blood.
For there is not only a propensity transmitted, but an actual disease of
the nervous system."--DR. WILLARD PARKER. [Footnote: The subject of
alcohol is continued in the chapter on the Nervous System.]
PRACTICAL QUESTIONS.
1. How do clothing and shelter economize food?
2. Is it well to take a long walk before breakfast?
3. Why is warm food easier to digest than cold?
4. Why is salt beef less nutritious than fresh? [Footnote: The French
Academicians found that flesh soaked in water so as to deprive it of its
mineral matter and juices, lost its nutritive value, and that animals fed
on it soon died. Indeed, for all purposes of nutrition, Liebig said it was
no better than stones, and the utmost torments of hunger were hardly
sufficient to induce them to continue the diet. There was plenty of
nutritive food, but there was no medium for its solution and absorption,
and hence it was useless.] 5. What should be the food of a man recovering
from a fever?
6. Is a cup of black coffee a healthful close to a hearty dinner?
7. Should iced water be used at a meal?
8. Why is strong tea or coffee injurious?
9. Should food or drink be taken hot?
10. Are fruitcakes, rich pastry, and puddings wholesome?
11. Why are warm biscuit and bread hard of digestion?
12. Should any stimulants be used in youth?
13. Why should bread be made spongy?
14. Which should remain longer in the mouth, bread or meat?
15. Why should cold water be used in making soup, and hot water in boiling
meat?
16. Name the injurious effects of overeating.
17. Why do not buckwheat cakes, with syrup and butter, taste as well in
July as in January?
18. Why is a late supper injurious?
19. What makes a man "bilious"?
20. What is the best remedy? _Ans_. Diet to give the organs rest, and
active exercise to arouse the secretions and the circulation.
21. What is the practical use of hunger?
22. How can jugglers drink when standing on their heads?
23. Why do we relish butter on bread?
24. What would you do if you had taken arsenic by mistake? (See Appendix.)
25. Why should ham and sausage be thoroughly cooked?
26. Why do we wish butter on fish, eggs with tapioca, oil on salad, and
milk with rice?
27. Explain the relation of food to exercise.
28. How do you explain the difference in the manner of eating between
carnivorous and herbivorous animals?
29. Why is a child's face plump and an old man's wrinkled?
30. Show how life depends on repair and waste.
31. What is the difference between the decay of the teeth and the constant
decay of the body?
32. Should biscuit and cake containing yellow spots of soda be eaten?
33. Tell how the body is composed of organs, how organs are made up of
tissues, and how tissues consist of cells.
34. Why do we not need to drink three pints of water per day?
35. Why, during a pestilence, are those who use liquors as a beverage the
first, and often the only victims?
36. What two secretions seem to have the same general use?
37. How may the digestive organs be strengthened?
38. Is the old rule, "after dinner sit awhile," a good one?
39. What would you do if you had taken laudanum by mistake? Paris Green?
Sugar of lead? Oxalic acid? Phosphorus from matches? Ammonia? Corrosive
sublimate? (See p. 265.)
40. What is the simplest way to produce vomiting, so essential in case of
accidental poisoning?
41. In what way does alcohol interfere with the digestion?
42. Is alcohol assimilated?
43. What is the effect of alcohol on the albuminous substances?
44. Is there any nourishment in beer?
45. Show how the excessive use of alcohol may first increase, and,
afterward, decrease, the size of the liver.
46. Will liquor help one to endure cold and exposure?
47. What is a fatty degeneration of the kidneys?
48. Contrast the action of alcohol and water in the body.
49. Is alcohol, in any proper sense of the term, a food?
50. Does liquor strengthen the muscles of a working man?
51. Is liquor a wholesome "tonic"?
52. Is it a good plan to take a glass of liquor before dinner?
VII.
THE NERVOUS SYSTEM.
"Mark then the cloven sphere that holds
All thoughts in its mysterious folds,
That feels sensation's faintest thrill,
And flashes forth the sovereign will;
Think on the stormy world that dwells
Lock'd in its dim and clustering cells;
The lightning gleams of power it sheds
Along its hollow, glassy threads!"
"As a king sits high above his subjects upon his throne, and from it
speaks behests that all obey, so from the throne of the brain cells is all
the kingdom of a man directed, controlled, and influenced. For this
occupant, the eyes watch, the ears hear, the tongue tastes, the nostrils
smell, the skin feels. For it, language is exhausted of its treasures, and
life of its experience; locomotion is accomplished, and quiet insured.
When it wills, body and spirit are goaded like overdriven horses. When it
allows, rest and sleep may come for recuperation. In short, the slightest
penetration may not fail to perceive that all other parts obey this part,
and are but ministers to its necessities."--Odd Hours of a Physician.
ANALYSIS OF THE NERVOUS SYSTEM.
_
| 1. THE STRUCTURE
| _
| _ | 1. _Description._
| | 1. The Brain........| 2. _The Cerebrum._
| | |_3. _The Cerebellum._
| | _
| | 2. The Spinal Cord..| 1. _Its Composition._
| | |_2. _Medulla Oblongata._
| | _
| 2. ORGANS OF | | 1. _Description._
| THE NERV- | | 2. _Motory and Sensory._
| OUS SYSTEM..| | 3. _Transfer of Pain._
| | | 4. _The Spinal Nerves--
| | | 31 Pairs._
| |_3. The Nerves.......| 5. _The Cranial Nerves--
| | 12 Pairs._
| | 6. _Sympathetic System._
| | 7. _Crossing of Cords._
| | 8. _Reflex Action._
| | 9. _Uses of Reflex
| |_ Action_
| _
| | 1. Brain Exercise.
| | 2. Connection between Brain Growth and Body Growth.
| 3. HYGIENE.....| 3. Sleep.
| | 4. Effect of Sleeping Draughts.
| |_5. Sunlight.
|
| 4. WONDERS OF THE BRAIN.
| _
| | 1. Alcohol (Con'd.)
| | _ | 1. _Stage of Excitement._
| || | 2. _Stage of Muscular
| || | Weakness._
| || 1. Effect of Alco- | 3. _Stage of Mental
| || hol upon the | Weakness._
| || Nervous System | 4. _Stage of Unconscious-
| || |_ ness._
| ||
| || 2. Effect upon the Brain
| ||_3. Effect upon the Mental and Moral Powers.
| |
| | 2. Tobacco.
| | _
| || 1. Constituents of Tobacco.
| 5. ALCOHOLIC || 2. Physiological Effects.
| DRINKS AND|| 3. Possible Disturbances produced by Smoking.
|_ NARCOTICS.|| 4. Influence upon the Nervous System.
|| 5. Is Tobacco a Food?
||_6. Influence of Tobacco on Youth.
| _
| | 1. _Description._
| 3. Opium............| 2. _Physiological
| |_ Effects._
| 4. Chloral Hydrate.
| 5. Chloroform.
|_6. Cocaine.
THE NERVOUS SYSTEM. [Footnote: The organs of circulation, respiration, and
digestion, of which we have already spoken, are often called the
vegetative functions, because they belong also to the vegetable kingdom.
Plants have a circulation of sap through their cells corresponding to that
of the blood through the capillaries. They breathe the air through their
leaves, which act the part of lungs, and they take in food which they
change into their own structure by a process which answers to that of
digestion. The plant, however, is a mere collection of parts incapable of
any combined action. On the other hand, the animal has a nervous system
which binds all the organs together.]
STRUCTURE.--The nervous system includes the _brain_, the _spinal
cord_, and the _nerves_. It is composed of two kinds of matter--
the _white_, and the _gray_. The former consists of minute,
milk-white, glistening fibers, sometimes as small as 1/25000 of an inch in
diameter; the latter is made up of small, ashen-colored cells, forming a
pulp-like substance of the consistency of blancmange. [Footnote: In
addition to the cells, the gray substance contains also nerve fibers
continuous with the white fibers, but generally much smaller. These form
half the bulk of the gray substance of the spinal cord, and a large part
of the deeper layer of the gray matter in the brain.--LEIDY'S
_Anatomy_, p. 507.] This is often gathered in little masses, termed
ganglions (_ganglion_, a knot), because, when a nerve passes through
a group of the cells, they give it the appearance of a knot. The nerve
fibers are conductors, while the gray cells are generators, of nervous
force. [Footnote: What this force is we do not know. In some respects it
is like electricity, but, in others, it differs materially. Its velocity
is about thirty three meters per second.--_Popular Physics_, p. 244,
Note.] The ganglia, or nervous centers, answer to the stations along a
telegraphic line, where messages are received and transmitted, and the
fibers correspond to the wires that communicate between different parts.
FIG. 50.
[Illustration: _The Nervous System._ A, _cerebrum_; B,
_cerebellum._]
The BRAIN is the seat of the mind. [Footnote: In proportion to the rest
of the nervous matter in the body, it is larger in man than in any of the
lower animals. It is the function which the brain performs that
distinguishes man from all other animals, and it is by the action of his
brain that he becomes a conscious, intelligent, and responsible being. The
brain is the seat of that knowledge which we express when we say _I_.
I know it, I feel it, I saw it, are expressions of our individual
consciousness, the seat of which is the brain. It is when the brain is at
rest in sleep that there is least consciousness. The brain may be put
under the influence of poisons, such as alcohol and chloroform, and then
the body is without consciousness. From these and other facts the brain is
regarded as the seat of _consciousness_.--LANKESTER.] Its average
weight is about fifty ounces. [Footnote: Cuvier's brain weighed 64 1/2
ounces; Webster's, 53 1/2 ounces; James Fisk's, 58 ounces; Ruloff's, 59
ounces; an idiot's, 19 ounces. See Table in FLINT'S _Nervous
System_.] It is egg-shaped, and, soft and yielding, fills closely the
cavity of the skull. It reposes securely on a water bed, being surrounded
by a double membrane _(arachnoid)_, delicate as a spider's web, which
forms a closed sac filled, like the spaces in the brain itself, with a
liquid resembling water. Within this, and closely investing the brain, is
a fine tissue (_pia mater_), with a mesh of blood vessels which dips
down into the hollows, and bathes them so copiously that it uses one fifth
of the entire circulation of the body. Around the whole is wrapped a tough
membrane (_dura mater_), which lines the bony box of the skull, and
separates the various parts of the organ by strong partitions. The brain
consists of two parts--the _cerebrum_, and the _cerebellum_.
The CEREBRUM fills the front and upper part of the skull, and comprises
about seven eighths of the entire weight of the brain. As animals rise in
the scale of life, this higher part makes its appearance. It is a mass of
white fibers, with cells of gray matter sprinkled on the outside, or
lodged here and there in ganglia. It is so curiously wrinkled and folded
as strikingly to resemble the meat of an English walnut. This structure
gives a large surface for the gray matter,--sometimes as much as six
hundred and seventy square inches. The convolutions are not noticeable in
an infant, but increase with the growth of the mind, their depth and
intricacy being characteristic of high mental power.
FIG. 51.
[Illustration: _Surface of the Cerebrum._]
The cerebrum is divided into two hemispheres, connected beneath by fibers
of white matter. Thus we have two brains, [Footnote: This doubleness has
given rise to some curious speculations. In the case of the hand, eye,
etc, we know that the sensation is made more sure. Thus we can see with
one eye, but not so well as with both. It is perhaps the same with the
brain. We may sometimes carry on a train of thought, "build an air castle"
with one half of our brain, while the other half looks on and watches the
operation; or, we may read and at the same time think of something else.
So in delirium, a patient often imagines himself two persons, thus showing
a want of harmony between the two halves.--DRAPER, _Human
Physiology_, p. 320.] as well as two hands and two eyes. This provides
us with a surplus of brains, as it were, which can be drawn upon in an
emergency. A large part of one hemisphere has been destroyed without
particularly injuring the mental powers, [Footnote: A pointed iron bar,
three and a half feet long and one inch and a quarter in diameter, was
driven by the premature blasting of a rock completely through the side of
the head of a man who was present. It entered below the temple, and made
its exit at the top of the forehead, just about the middle line. The man
was at first stunned, and lay in a delirious, semistupefied state for
about three weeks. At the end of sixteen months, however, he was in
perfect health, with wounds healed and mental and bodily functions
unimpaired, except that sight was lost in the eye of the injured side.--
DALTON. It is noticeable, however, that the man became changed in
disposition, fickle, impatient of restraint, and profane, which he was not
before. He died epileptic, nearly thirteen years after the injury. The
tamping iron and the skull are preserved in the Warren Anatomical Museum,
Boston.]--just as a person has been blind in one eye for a long time
without having discovered his loss. The cerebrum is the center of
intelligence and thought. [Footnote: In man, the cerebrum presents an
immense preponderance in weight over other portions of the brain; in some
of the lower animals, the cerebrum is even less in weight than the
cerebellum. Another interesting point is the development of cerebral
convolutions in certain animals, by which the relative amount of gray
matter is increased. In fishes, reptiles, and birds, the surface of the
hemispheres is smooth; but, in many mammalia, especially in those
remarkable for intelligence, the cerebrum presents a greater or less
number of convolutions, as it does in the human subject.--FLINT. The
average weight of the human brain in proportion to the entire body is
about 1 to 36. The average of mammalia is 1 to 186; of birds, 1 to 212; of
reptiles, 1 to 1,321; and of fishes, 1 to 5,668. There are some animals in
which the weight of the brain bears a higher proportion to the body than
it does in man; thus in the blue-headed tit, the proportion is as 1 to 12;
in the goldfinch, as 1 to 24; and in the field mouse, as 1 to 31. "It does
not hence follow, however, that the _cerebrum_ is larger in
proportion; in fact, it is probably not nearly so large; for in birds and
rodent animals the sensory ganglia form a very considerable portion of the
entire brain. M. Baillarger has shown that the _surface_ and the
_bulk_ of the cerebral hemispheres are so far from bearing any
constant proportion to each other in different animals that,
notwithstanding the depth of the convolutions in the human cerebrum, its
bulk is two and a half times as great in proportion to its surface as it
is in the rabbit, the surface of whose cerebrum is smooth. The _size_
of the cerebrum, considered alone, is not, however, a fair test of its
intellectual power. This depends upon the quantity of _vesicular
matter_ which it contains, as evinced not only by superficial area, but
by the number and depth of the convolutions and by the thickness of the
cortical layer."--CARPENTER.] Persons in whom it is seriously injured or
diseased often become unable to converse intelligently, both from
inability to remember words and from loss of power to articulate them.
THE CEREBELLUM lies below the cerebrum, and in the back part of the head
(Fig. 50). It is about the size of a small fist. Its structure is similar
to that of the brain proper, but instead of convolutions it has parallel
ridges, which, letting the gray matter down deeply into the white matter
within, give it a peculiar appearance, called the _arbor vitæ_, or
tree of life (Fig. 55). This part of the brain is the center for the
control of the voluntary muscles, [Footnote: The exact nature of the
functions of the cerebellum is one of those problems concerning which
there is no unanimity of opinion amongst physiologists. It may be
premised, however, that the knowledge we at present possess does enable us
to come to one very important conclusion with respect to the functions of
the cerebellum,--it enables us to say that this organ has no independent
function either in the province of mind or in the province of motility.
And we may perhaps safely affirm still further, that the cerebellum is
much more intimately concerned with the production of bodily movements
than with the evolution of mental phenomena. The anatomical distinctness
of the cerebellum from the larger brain and other parts of the nervous
system is more apparent than real....That there is an habitual community
of action between the cerebellum and the spinal cord is, I believe,
doubted by none, and the fact that an intimate functional relationship
exists between the cerebrum and the cerebellum is shown by the
circumstance that atrophy of one cerebral hemisphere entails a
corresponding atrophy of the opposite half of the cerebellum. The
subordinate or supplementary nature of the cerebellar function, however,
in this latter relation seems equally well shown by the fact that atrophy
of one side of the cerebellum (when it occurs as the primary event) does
not entail any appreciable wasting in the opposite half of the cerebrum.
What other conclusion can be drawn? If the cutting off of certain cerebral
stimuli leads to a wasting of the opposite half of the cerebellum, this
would seem to show that each half of the cerebellum is naturally called
into activity in response to, or conjointly with, the opposite cerebral
hemisphere. Whilst conversely, if atrophy of one half of the cerebellum
does not entail a relative diminution in the opposite cerebral hemisphere,
this would go to show that the cerebral hemispheres do not act in response
to cerebellar stimuli, since their nutrition does not suffer when such
stimuli are certainly absent. The action of the cerebrum is therefore
shown to be primary, whilst that of the cerebellum is secondary or
subordinate in the performance of those functions in which they are both
concerned.--H. CHARLTON BASTIAN, _Paralysis from Brain Disease_.]
particularly those of locomotion. Persons in whom it is injured or
diseased walk with tottering and uncertain movements as if intoxicated,
and can not perform any orderly work.
THE SPINAL CORD occupies the cavity of the backbone. It is protected by
the same membranes as the brain, but, unlike it, the white matter is on
the outside, and the gray matter is within. Deep fissures separate it into
halves (Fig. 50), which are, however, joined by a bridge of the same
substance. Just as it starts from the brain, there is an expansion called
the _medulla oblongata_ (Fig. 55).
THE NERVES are glistening, silvery threads, composed, like the spinal
cord, of white matter without and gray within. They ramify to all parts of
the body. Often they are very near each other, yet are perfectly distinct,
each conveying its own impression. [Footnote: Press two fingers together,
and, closing the eyes, let some one pass the point of a pin lightly from
one to the other; you will be able to tell which is touched, yet if the
nerves came in contact with each other anywhere in their long route to the
brain, you could not thus distinguish.] Those which carry the orders of
the mind to the different organs are called the _motory_ nerves;
while those which bring back impressions which they receive are styled
_sensory_ nerves. If the sensory nerve leading to any part be cut,
all sensation in that spot will be lost, while motion will remain; if the
motory nerve be cut, all motion will be destroyed, while sensation will
exist as before.