Gastric juice

“ The question is often asked why the stomach itself is not digested by the gastric juice, since it belongs to the albuminous substances. Some have assigned as the probable reason that life protects that organ, and assert that living tissues can not be digested; but the fallacy of this has been clearly shown by experiments that have been made with living tissues in the course of scientific research. The latest opinion is that the blood which circulates so freely through the vessels of the lining of the stomach, being alkaline, protects the tissue against the acidity of the gastric juice. ”

“ In many cases the glands that secrete the gastric juice are feeble; in others they seem cramped, and far from ready to act when food is presented. The hot water has the same effect on them as it has everywhere else on the body—that of stimulating the circulation and bringing about natural action. It looks a very frail remedy; but when we can, as it were, see these glands opening and filling with arterial blood the instant they are bathed in this same water, and see how ready they become to supply gastric juice for digestion, the remedy does not look so insignificant. ”

“ The solvent power of the gastric juice is evidently controlled by the vital principle of life; while the gastric juice of a healthy stomach acts vigorously upon the hardest kinds of food; yet sometimes, when it comes in contact with anything possessed of the principles of life, its power is stayed—worms, while living, are not affected by it, but when destroyed, are often digested. ”

“ It excites the sides of the stomach, and by this promotes the secretion of the juice by which food is dissolved. It often occurs, that if but a minute quantity of fat has been taken, it envelops the food in the stomach; and as the gastric juice dissolves fat only with great difficulty, this food often remains undigested in the stomach, and nutrition then is carried on but defectively. Digestion, therefore, may be greatly improved, if the stomach is so affected as to secrete a greater quantity of gastric juice ”

“ Walther for the pancreatic juice, and by my own for the gastric juice. If this sequence of foods, therefore, holds good for healthy people, it must be even more strictly adhered to in pathological conditions. Thus, when a person has no appetite, or only a weak one, he has no psychic juice or only very little; consequently, the meal must in every case be begun with a strong chemical excitant—for example, with a solution of the extractives of flesh. [Pg 268] Otherwise solid foods, particularly if they do not consist of meat, would remain long in the stomach without any digestion whatever. ”

“ The most remarkable property of the gastric juice is unquestionably the power which it possesses of dissolving and reducing to the appearance of a soft thickish fluid mass every thing in the shape of food which is submitted to its action,—while it exerts no perceptible influence on living or inorganic matter; for, so far as is yet known, nothing which is not organized, or which is still alive, can serve as nutriment for the animal frame. ”

“ When the food reaches the stomach, gastric juice is secreted. This juice contains a ferment called pepsin and hydrochloric acid. Pepsin is only active in an acid media. Starch digestion proceeds in the stomach to such a time—stated as from 15 to 30 minutes—when the acid gastric juice has been poured out in sufficient quantity to neutralise the alkalinity of the saliva. The gastric juice acts upon the proteids only. After a time the liquefied contents of the stomach are passed into the first portion of the small intestine, called the duodenum. ”

“ The pancreatic juice appears to have the function of digesting whatever alimentary substance has escaped digestion by the saliva, gastric juice, and bile. It is a clear, viscid liquid of alkaline reaction. It rapidly changes starch into glucose. It converts proteids into peptones and emulsifies fats. While the gastric juice requires an acid medium for the performance of its digestive function, the pancreatic juice requires one that is alkaline. ”

“ As chemical factors, water and salts are the two necessary substances for gastric digestion, since the enzymes in the juices cannot act except in their presence.
Alkaline carbonates and fatty foods both check the flow of gastric juice, and retard digestion. The psychic factors which result in a stimulation of the secretory cells in the stomach are exerted through the sight, smell, and taste. One often hears the expression: “The food looked, smelled, or tasted so good that it made my mouth water.” ”

“ In cream the fat is held in the form of an emulsion which allows it to mingle freely with water. As previously stated, each atom of fat is surrounded with a film of casein. The gastric juice has no more power to digest casein than it has free fat, and the little particles of fat thus protected are carried to the small intestines, where the pancreatic juice digests them, and on their way they do not interfere with the stomach digestion of other foods, as the presence of butter and other free fats may do. ”

“ The gastric juice, of which about seventy ounces is formed by the stomach daily, con [Pg 100] tains in addition to hydrochloric acid, a quantity of pepsin, which with the acid dissolves all sorts of proteids or albuminous substances, like meat and eggs; and it also contains rennet, which coagulates milk. The gastric juice digests proteids by converting them into pepsin, an exceedingly soluble substance which passes readily into the blood.
The bile manufactured by the liver has the function of digesting fats. Fats are not changed chemically, as are starches and proteids. ”

“ This first secreted juice is called “appetite juice,” and is an important factor in the complicated process of digestion. “The appetite is the first and mightiest exciter of the secretory nerves of the stomach.” (Pawlow, p. 75.) Pawlow’s results have been confirmed in man by Hornborg, Umber, Bickel, and 428Cade and Latarjet. The mere chewing of appetizing food, for instance, is followed by a copious discharge of gastric juice, while chewing of rubber and distasteful substances has a negative result. Depressing emotions inhibit the secretion of juice (Bickel) . ”

“ At times there exists a certain condition of inactivity of the digestive organs when the gastric juice is not secreted in sufficient quantity, and perfectly sound food may undergo fermentation and set up an attack. ”

“ The gastric juice is partly prevented from secreting and that which is secreted is unhealthy, the ducts of the liver and pancreatic gland are prevented from performing their healthy functions and consequently the food is not taken in due quantity to nourish the system, and what is taken is not properly digested, for the want of a free and healthy action of the digestive functions. ”

“ Gastric juice is secreted continuously, but quantities sufficiently large for examination are not usually obtainable from the fasting stomach. In clinical work, therefore, it is desirable to stimulate secretion with food—which is the natural and most efficient stimulus—before attempting to collect the gastric fluid. Different foods stimulate secretion to different degrees ”

“ The stomach accustomed for a time to the smallest quantity, is no longer able to provide gastric juice sufficient for the purposes of digestion; and being irritated by continued craving, its secretions are vitiated and its sensibility exalted to such a degree as to require the wisest management to enable it to regain its healthy tone. ”

“ Punctuality at meals is absolutely essential for the maintenance of good health. The stomach gets into the habit of secreting its digestive juices at certain times, as meals fall due. If it does not meet with the food it has come to act upon, it will seize upon the stomach wall and cause pain and a nauseous sense of sinking. And these sensations will probably be followed by a headache, for the gastric juice, which is one of our vital agents, is nothing less than an irritant poison if it has no work to do. It is like a man loitering about an office or workshop when trade is slack. ”

“ Fahrenheit, and thus no taste of fat is produced. For this purpose he threw into the washtub containing the artificial gastric juice about two liters per hundred kilograms of greasy substance. This gastric juice is made with the half of a stomach of a pig or sheep, well washed, and three liters of water containing thirty grams of biphosphate of lime. ”

“ Exercise in the open air is most valuable for promoting an 273appetite, and persons sitting constantly in close places often lack this; thus their gastric juice, which is indispensable to a thorough digestion (see chapter on hygiene of eating—how to obtain an appetite) fails, and eating without this juice their food will not be well digested and will create stomach troubles, which are extremely frequent in such office workers, but rarer in the case of peasants, coachmen, and other fortunate individuals whose occupation keeps them in the fresh open air. ”

“ In a state of health the abundantly secreted gastric juice speedily redissolves the chief part of the curd in the stomach, while when it has passed into the intestine the alkaline bile which there becomes mixed with it, completes its solution, and converts the whole into a fluid which closely resembles one of the chief elements of the blood, is consequently very easily taken up by the minute vessels whose office it is to do so, and thus supplies with nourishment the whole body. ”

“ In like manner, when meat out of the stomach was placed in a vial containing gastric juice, its solution was uniformly accelerated by gentle agitation, which acted simply by removing the coating of chyme as it formed on the surface, and thus affording to the gastric fluid an easier access to the undigested portions below. ”