ABSORPTION.
387. ABSORPTION is the process by which the materials of nutrition are
removed from the alimentary canal, to be conveyed into the circulatory
vessels. It is likewise the process by which the particles of matter
that have become injurious, or useless, are removed from the mass of
fluids and solids of which the body is composed. These renovating and
removing processes are performed by two sets of vessels
ANATOMY OF THE LYMPHATIC VESSELS.
388. The vessels that act exclusively for the growth and renovation of
the system, are found only in the alimentary canal. They are called
lacteals. The vessels whose sole function is to remove particles of
matter already deposited, are called _Lym-phat'ics_. The radicles, or
commencement of the veins, in many, and it may be in all parts of the
body, perform the office of absorption.
_Observation._ This fact accounts for the capacity of the venous
system exceeding the arterial. Had the veins no other function to
perform, beside returning the blood that had been distributed by the
arteries, it would be reasonable to suppose that this system would be
less than the arterial, but the reverse is known to be true.
389. The LYMPHATIC VESSELS, in structure, resemble the lacteals. They
exist in great numbers in the skin and mucous membranes, particularly
those of the lungs. Though no lymphatics have been traced to the
brain, it is presumed that they exist there, as this part of the body
is not exempt from the composition and decomposition, which are
perpetual in the body. These vessels are extremely minute at their
origin, so that in many parts of the system they cannot be detected
without the aid of a microscope.
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387. Define absorption. 388-391. _Give the anatomy of the lymphatic
vessels._ 388. What are those vessels called that act exclusively for
the growth and renovation of the body? Those whose office is to remove
the atoms already deposited? What other vessels perform the office of
absorption? Give observation. 389. Describe the lymphatics.
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[Illustration: Fig. 82. A single lymphatic vessel, much magnified.]
[Illustration: Fig. 83. The valves of a lymphatic trunk.]
[Illustration: Fig. 84. 1, A lymphatic gland with several vessels passing
through it.]
390. The lymphatic vessels, like the veins, diminish in number as they
increase in size, while pursuing their course toward the large veins
near the heart, into which they pour their contents. The walls of
these vessels have two coats of which the external one is cellular,
and is capable of considerable distention. The internal coat is folded
so as to form valves, like those in the veins. Their walls are so
thin, that these folds give them the appearance of being knotted.
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What is represented by fig. 82? By fig. 83? By fig. 84? 390. In what
respect do these vessels resemble the veins of the system? Give the
structure of their coats.
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391. At certain points, the lymphatic vessels pass through distinct,
soft bodies, peculiar to themselves, which are called _lymphatic
glands_, which are to these vessels what the mesenteric glands are to
the lacteals. The lymphatic glands vary in form and in size. They are
extremely vascular, and appear to consist of a collection of minute
vessels. These glands are found in different parts of the body, but
are most numerous in the groins, axilla, or arm-pits, neck, and
cavities of the chest and abdomen.
_Observation._ From exposure to cold, these glands are frequently
enlarged and inflamed. They are known under the name of "kernels."
They are often diseased, particularly in scrofula, or "king's evil."
PHYSIOLOGY OF THE LYMPHATIC VESSELS.
392. Though the lacteals and lymphatics resemble each other in their
structure and termination, yet they differ as to the nature of the
fluids which they convey, as well as the nature of their functions.
The lacteals open into the small intestine, and possess the power of
rejecting all substances in the passing aliment, but the chyle. The
lymphatics, on the contrary, not only imbibe all the various
constituents of the body, both fluid and solid, but they sometimes
absorb foreign and extraneous substances, when presented to their
mouths, as in vaccination.
393. The varieties of absorption are, the _In-ter-sti'tial_,
_Rec-re-men-ti'tial_, _Ex-cre-men-ti'tial_, _Cu-ta'ne-ous_,
_Res-pi'ra-to-ry_, _Ve'nous_, and the _Lac'te-al_.
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391. Describe the lymphatic glands. What observation is given in
regard to these glands? 392-403. _Give the physiology of the lymphatic
vessels._ 392. Explain the difference between the lacteals and
lymphatics 393. Name the varieties of absorption.
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394. INTERSTITIAL absorption is that change which is constantly going
on in the animal economy among the particles of matter of which every
texture is composed. The ordinary functions of the body, in health,
require incessant action of the lymphatics; the circulatory system,
with its myriads of small vessels, is constantly depositing new atoms
of matter, which become vitalized, and perform a course of actions,
then die, or become useless. These old atoms are removed by the
absorbent system. Thus, wherever there is a minute artery to deposit a
living particle of matter, there is a lymphatic vessel, or venous
radicle, to remove it as soon as it shall have finished its particular
office.
395. The action of the lymphatic vessels counterbalances those of
nutrition, and thus the form and size of every part of the body is
preserved. When their action exceeds that of the nutrient vessels, the
body emaciates; when it is deficient, plethora is the result. In
youth, they are less active than the nutrient vessels, and the limbs
are plump; but in later periods of life, we find these actions
reversed, and the body diminishes in size. It is not unfrequent that
wens, and other tumors of considerable size, disappear, and even the
entire bone of a limb has been removed from the same general cause.
The effused fluids of bruises are also removed by absorption.
_Observations._ 1st. When little or no food is taken into the stomach,
life is supported by the lymphatic vessels and veins imbibing the fat
and reconveying it into the blood vessels. It is the removal of this
secretion which causes the emaciation of the face and extremities of a
person recovering from a fever. In consumption, the extreme
attenuation of the limbs is caused by the absorption, not only of the
fat, but also of the muscles and more solid parts of the system.
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394. What is interstitial absorption? Flow are the new atoms of matter
deposited? How removed? 395. What vessels do the lymphatics
counterbalance in action? What is the result when their action exceeds
that of the nutrient vessels? When it is less? Mention some instances
of active absorption. What causes the emaciated limbs of a person
recovering from fever? The extreme attenuation in consumption?
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2d. Animals which live in a half torpid state during the winter,
derive their nourishment from the same source. In other words, we may
say the starving animal lives for a time upon itself, eating up, by
internal absorption, such parts of the body as can be spared under
urgent necessity, to feed those organs and continue those functions
that are absolutely essential to life.
396. RECREMENTITIAL absorption is the removal of those fluids from the
system, which are secreted upon surfaces that have no external outlet.
These fluids are various, as the fat, the marrow, the synovia of
joints, serous fluids, and the humors of the eye. Were it not for this
variety of absorption, dropsy would generally exist in the cavities of
the brain, chest, and abdomen, from the continued action of the
secretory vessels.
397. EXCREMENTITIAL absorption relates to the fluids which have been
excreted, such as the bile, pancreatic fluid, saliva, milk, and other
secretions.
398. CUTANEOUS absorption relates to the skin. Here the lymphatic
vessels extend only to the cuticle, which they do not permeate. There
has been much diversity of opinion on the question of cutaneous
absorption; some maintaining that this membrane absorbs, while others
deny it. Many experiments have proved that the skin may absorb
sufficient nutriment to support life for a time, by immersing the
patient in a bath of milk or broth. It has been found that the hand,
immersed to the wrist in warm water, will absorb from ninety to one
hundred grains of fluid in the space of an hour.
399. Thirst may be quenched by applying moist clothes to the skin, or
by bathing. It is no uncommon occurrence, during a passage from one
continent to the other, for the saliva to become bitter by the
absorption of sea water. Medicinal substances, such as mercury,
morphine, and Spanish flies, are frequently introduced into the system
through the skin.
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396. What is recrementitial absorption? 397. Define excrementitial
absorption. 393. To what does cutaneous absorption relate? Is there a
diversity of opinion respecting this variety of absorption? What do
well attested experiments show? 399. What remark in reference to
quenching thirst? What agency conveys medicinal substances and
ointments into the system when tabbed on the skin?
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400. RESPIRATORY absorption has reference to the lungs. The mucous
membrane of these organs is abundantly supplied with lymphatic
vessels. By their action, substances finely pulverized, or in the form
of gas, are readily imbibed when inhaled into the lungs, such as
metallic vapors, odoriferous particles, _tobacco smoke_, and other
effluvia. In this way, contagious diseases are frequently contracted.
_Illustration._ In inhaling sulphuric ether, or letheon, it is
introduced into the vessels of the lungs in the form of vapor, and
through them it is rapidly conveyed to the brain, and thus influences
the nervous system.
401. VENOUS absorption is the function which the veins perform in
absorbing from the alimentary canal liquids of various kinds that have
been taken into the stomach and are not converted into chyle. In other
parts of the body, they also perform the common office of lymphatics.
402. LACTEAL, or digestive absorption has reference to the absorption
of chyle only, which is destined for the nutrition of the body.
403. Absorption is not only very abundant, but generally very rapid,
and all these varieties are maintained through life, except when
suspended by disease.
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400. What is said of respiratory absorption? How is letheon introduced
into the system? 401. Define venous absorption. 402. What is lacteal
absorption? 403. What is said of absorption?
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[Illustration: Fig. 85. A representation of the lymphatic vessels and
glands. 1, 2, 3, 4, 5, 6, The lymphatic vessels and glands of the lower
limbs. 7, Lymphatic glands. 8, The commencement of the thoracic duct. 9,
The lymphatics of the kidney. 10, Of the stomach. 11, Of the liver. 12,
12, Of the lungs. 13, 14, 15, The lymphatics and glands of the arm. 16,
17, 18, Of the face and neck. 19, 20, Large veins. 21, The thoracic duct.
26, The lymphatics of the heart.]
HYGIENE OF THE LYMPHATIC VESSELS.
404. By the action of the lymphatics, substances of an injurious, as
well as of a beneficial, character may be conveyed into the system.
These vessels, under certain conditions, are more active in their
office than at other periods; and it is of practical utility to know
what influences their action.
405. _The function of these vessels is increased by moisture, and
lessened by an active state of the lacteals._ Observation shows that
the ill-fed, and those persons that live in marshy districts, contract
contagious diseases more readily than those individuals who are well
fed, and breathe a dry and pure air.
406. _The air of the sick-room should be dry._ If due attention is not
given to ventilation, the clothing of the nurse and patient, together
with the air of the room, will be moistened by the exhalations from
the skin and lungs. This exhalation may contain a poison of greater or
less power, according to its quantity and degree of concentration, and
may be absorbed and reconveyed into the system, causing inflammatory
diseases, and not unfrequently death.
_Observations._ 1st. When we are attending a sick person a current of
air that has passed over the patient should be avoided. We may
approach with safety very near a person who has an infectious disease,
provided care is taken to keep on the side from which the currents of
air are admitted into the room.
2d. When we have been visiting or attending on a sick person, it is
judicious to change the apparel worn in the sick-room, and also give
the skin a thorough bathing. The outside garments, also, should be
aired, as poisonous matter may have penetrated the meshes of the
clothing.
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404-413. _Give the hygiene of the lymphatic vessels._ 404. What is
said respecting the action of the lymphatic vessels? 405. What
influences the function of these vessels? What does observation show?
406. Why should the air of the sick-room be dry? What suggestion when
we have been visiting or attending on the sick?
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407. _The stomach should be supplied with food of a nutrient and
digestible character, in proper quantities, and at stated periods._
The chyle formed from the food stimulates the lacteals to activity,
which activity is attended with an inactive state of the lymphatics of
the skin and lungs. Thus due attention should be given to the food of
the attendants on the sick, and the members of the family. Before
visiting a sick person it is judicious to take a moderate amount of
nutritious food.
_Observation._ Many individuals, to prevent contracting disease that
may be communicated from one person to another, use tobacco, either
chewed or smoked; and sometimes alcohol, with decoctions of bitter
herbs. These substances do not diminish, but tend to increase, the
activity of the lymphatics. Thus they make use of the means by which
the poisonous matter formed in the system of the diseased person, may
be more readily conveyed into their own.
408. _The skin and clothing, as well as the bed-linen, should be
frequently cleansed._ This will remove the poisonous matter that may
be deposited upon the skin and garments, which, if suffered to remain,
might be conveyed into the system by the action of the lymphatics.
This points also to a frequent change of the wearing apparel, as well
as the coverings of the bed. In visiting the unhealthy districts of
the South and West, the liability of contracting disease is much
lessened by taking a supply of food at proper periods, keeping the
skin and clothing in a clean state, the room well ventilated, and
avoiding the damp chills of evening.
409. _Absorption by the skin is most vigorous when the cuticle is
removed by vesication, or blistering._ Then external applications are
brought into immediate contact with the orifices of the lymphatics of
the skin, and by them rapidly imbibed and circulated through the
system. Thus arsenic applied to the cutaneous vessels, and strong
solutions of opium to extensive burns, have been absorbed in
quantities sufficient to poison the patient.
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407. Why should the stomach be supplied with food of a nutrient and
digestible character? What is said of the use of alcohol, or tobacco,
in preventing the introduction of the poisonous matter of contagious
diseases? 408. Why should the clothing and bed-linen be frequently
washed? What suggestion to persons in visiting the unhealthy districts
of the South and West? 409. When is cutaneous absorption most
vigorous? Why?
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410. _When the cuticle is only punctured or abraded, poisonous matter
may be introduced into the system._ The highly respected Dr. W., of
Boston, lost his life by poisonous matter from the body of a patient
subjected to a post mortem examination. He had removed from his
finger, previous to the examination, a "hang-nail," and the poison
from the dead body was brought in contact with the denuded part, and
through the agency of the lymphatics it was conveyed into the system.
411. Puncture any part of the cuticle with the finest instrument that
has upon its point the smallest conceivable quantity of the _vaccine
virus_, or small-pox matter, and it will be brought into contact with
the lymphatic vessels, and through their agency conveyed into the
system. The result is, that persons thus operated upon have the
small-pox, or the vaccine disease.
412. When we expose ourselves to any poisonous vapors, or handle
diseased animals or sick persons, safety and health require that the
cuticle be not broken or otherwise injured. In many instances, the
poisonous animal matter upon hides has been introduced into the
systems of tanners, through small ulcers upon their fingers or hands.
From these sores there would be seen small red lines extending up the
arm. These swelled tracts indicate an inflammation of the large
lymphatic trunks, that have been irritated and diseased by the
passage of poisonous matter through them into the system.
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410. Do the same results follow, if the cuticle is only punctured?
Relate an instance of death by the absorption of poisonous matter.
411. By what means is the vaccine matter introduced into the system?
412. What caution is necessary when we expose ourselves to poisonous
vapors?
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_Observation._ A distressing illustration of the absorption of
deleterious substances from the surface of a sore, is seen in the
favorite experiments of that class of "quacks," who style themselves
"cancer doctors." With them, every trifling and temporary enlargement,
or tumor, is a cancer. Their general remedy is arsenic; and happy is
the unfortunate sufferer who escapes destruction in their hands, for
too frequently their speedy cure is death.
413. In case of an accidental wound, it is best immediately to bathe
the part thoroughly in pure water, and to avoid all irritating
applications. In some instances, it would be well to apply _lunar
caustic_ immediately. When handling or shrouding dead bodies, or
removing the skin from animals that have died of disease, it would
be well to lubricate the hands with olive-oil or lard. This affords
protection to the minute portions of the skin, from which the cuticle
may be removed. In all cases where there is an ulcer or sore, the
part should be covered with something impervious to fluids, as
court-plaster, before exposing the system to any animal, vegetable,
or mineral poison.
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413. What direction is given when the cuticle is broken? What
suggestion is given when shrouding dead bodies?
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