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

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 182 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.

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.

Fig. 82. A single lymphatic vessel, much magnified.

Fig. 83. The valves of a lymphatic trunk.

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 183 valves, like those in the veins. Their walls are so thin, that these folds give them the appearance of being knotted.

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.

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.”

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.

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.

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.

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?

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 186 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.

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?

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.

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?

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.

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?

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 190 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.

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?

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 191 trunks, that have been irritated and diseased by the passage of poisonous matter through them into the system.

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?

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.

413. What direction is given when the cuticle is broken? What suggestion is given when shrouding dead bodies?