Peculation

“ The pancreatic secretion contains three separate and distinct ferments, which act respectively upon carbohydrate, protein, and fat. The absorption of fat, however, is materially assisted also by the action of the bile.
A part of what we eat always escapes digestion; the unused portion, it has been estimated, is somewhat less than one-tenth of an ordinary mixed diet. The residue from vegetables is notably larger than the residue from meat. The undigested portions of all the food- stuffs collect in the lowermost portion of the intestine and form a part of the feces. ”

“ Now, we do find in the liver itself and in the bile a ferment having the same diastatic power as the pancreatic juice, but it does not appear in such quantities as one would expect if the whole of the pancreatic ferment were simply reëxcreted by the liver along with the bile, and, as we have no evidence that the ferment is destroyed during its action in the intestine, we are naturally led to think that it may undergo a change in the liver, the converse of that which it undergoes in the pancreatic gland during the process of secretion. ”

“ Hitherto we have been accustomed to regard the phases of digestion, gastric digestion, pancreatic digestion, and intestinal digestion, as almost separate processes, any of which we might increase indefinitely without doing any harm to the patient. We forget the relation which each bears to the other; and yet such a relation undoubtedly exists, for we find that when pepsin is mixed with bile it is precipitated and rendered inert. Further transformation of foods by the gastric juice is thus arrested as soon as the chyme leaves the stomach. ”

“ They are dissolved in this fluid. Some others are soluble in dilute acid. These too are dissolved here. Albumen, and matters like it, are reduced to solution by the aid of the pepsin, which is the principle of digestion. But there are some few mineral bodies, and many vegetable substances, as fats and resins, which cannot be thus dissolved by the juice of the stomach. They are soluble, more or less, in a weak alkaline fluid; and such a fluid is the bile, which is poured out [Pg 22] into the first portion of the intestine. They too are reduced to solution and absorbed. ”

“ In this stomach it is digested, and from the digested mass the chyle is formed, which, being absorbed by the lacteal vessels, is afterwards thrown into the mass of blood, and becomes the principle of nutrition to all the solids and fluids of the body. The intention of rumination, or chewing the cud, seems to be, that the food may be sufficiently comminuted, that, being more fully acted on by the stomachs, it may afford the greatest possible portion of nutritive juices. ”

“ The stomach has three coats,—the outermost, or peritoneum, which constitutes the common covering of all the intestines; the muscular or fibrous coat, which acts upon, and mingles the food, and prepares it for digestion; and the mucous or villous coat, which is peculiarly developed in the pig, and into which open the mouths of numerous little vessels, conveying the gastric juice to the semi-digested food, and by its action conveying it into a pultaceous fluid, commonly called chyme. ”

“ That of the liver is largely excretion or refuse from the blood without direct action on the food, but it enables the pancreatic juice to do its work by making the food again alkaline, and stimulates the muscular coats of the intestine to force its contents along. That of the pancreas is the most important digestive fluid in the body, containing many ferments; it acts alike on proteids, carbohydrates, and fats—in fact, digests everything—so that the rest of the long tube is freed from any more laborious duty than absorbing them as they pass. ”

“ In this pitiable disease, through the valve of the colon, through the pylorus, the cardia, and the pharinx, are ejected, first, the contents of the stomach and intestines, with the excrement and even clysters themselves; then the fluid from the lacteals, which is now poured into the intestines by their retrograde motions, is thrown up by the mouth; and, lastly, every fluid, which is absorbed by the other lymphatic branches, from the cellular membrane, the skin, the bladder, and all other cavities of the body ”

“ We are at liberty, however, to suppose that the fat on the one hand is of importance for the inhibition of the gastric glands, and the alkalinity on the other for the restraint of the pancreas. Thus the gastric glands and the pancreas, notwithstanding the presence of excitants, are maintained by milk at a certain but not too high degree of activity, a matter which is in every way desirable in consideration of the easy digestibility of its constituents. ”

“ Food when taken in through the wall of the body forms little pellets, which become surrounded by a digestive liquid exuded from the enclosing mass into rounded cavities or extemporised stomachs. Minute granules are seen to circulate in the gelatinous interior, and may be substitutes for blood-cells, and the outer layer of the « 61 » body is capable of protrusion in any direction into long processes, which are very mobile, and used for locomotion and prehension. ”

“ And it is not at all strange that they should, since there is so much pressure from within, so much pressure downward, and so much pressure from without—all through the requirements of fashion, indulgence, and ignorance. But the stomach, upper portion of the duodenum, and small intestine, cæcum, the ascending colon, and especially the transverse colon and sigmoid flexure, are susceptible to various forms of displacement, inhibiting the ready flow or passage of food stuffs, gases, and feces from one segment of the digestive apparatus to another, until the vent is reached. ”

“ Available Foods.—It must be borne in mind that the food must not be too concentrated in character or it will be so completely absorbed as to leave little or no residue for the feces, and since the waste products of metabolism, both of food and body materials, must be eliminated, a certain amount of fecal matter is necessary to assist in this work. ”

“ The muscles in the colon only contract when they are stretched, so it is the volume of the fecal matter stretching the large intestine that triggers the muscles to push the waste material along toward the rectum and anus.
Eating food lacking fiber greatly reduces the volume of the chyme and slows peristalsis. But moving through fast or slow, the colon still keeps on doing another of its jobs, which is to transfer the water in the chime back into the bloodstream, reducing dehydration. So the longer chime remains in the colon, the dryer and harder and stickier it gets. ”

“ It happens, however, that the next of the digestive juices to act upon the food are the pancreatic juice and bile, which are secreted respectively by the pancreas and liver, and are poured into the small intestine by ducts from these organs just a few inches beyond the outlet sphincter from the stomach. In order for these juices to mix well with the food it is important that only a little food come into the small intestine at a time. ”

“ 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. ”

“ If the patient’s vital powers are low, the milk may be peptonised by using Fairchild’s powders or by adding a little of Benger’s Liquor Pancreatices. In cases when milk cannot be taken in sufficient amount, animal food may be given in the form of plain meat broth. ”

“ Here the bile and the pancreatic juice, breaking up the fat into tiny{122} particles, mix fat, and broken meat, and empty wrappings, and salts, and water, all together into a thick, dirty, yellowish cream. Squeezed along the intestine by the contraction of the muscular walls, the goodness of this cream is little by little sucked up. The fat goes drop by drop, particle by particle, into the lacteals, and so away into the blood. The proteids, more and more dissolved the further they travel along the canal, soak away into blood-vessel or into lacteal. ”

“ The secretion of the pancreas also contains a very active ferment, which, on entering the bowel, meets and mixes with another ferment four times as powerful as gastric juice, which completes the digestion of the proteids.
Meantime, the secretions of Lieberkühn's glands (of which there are immense numbers in the small intestine) are further aiding the digestion of the chyme, while the liver (the largest and most important gland in the body) sends its ferments, and the gall-bladder its bile, which further emulsifies the fatty acids and glycerin until they are ready to be absorbed. ”

“ The pancreas is a gland near the stomach; it secretes the juice known as pancreatic and pours it into the duodenum, or small intestine, which—some ten or fifteen feet in length, is folded about it. To prevent intestinal indigestion there must be an abundant flow of pancreatic juice, and this flow is stimulated by the vinegar in the salad we eat and other acids in our food. ”

“ The cells lining the oesophagus resemble ectodermal cells; those lining the stomach are nearly all gland-cells, and obviously secrete the digestive juice. The powerful muscles of this portion of the gut produce a strong peristalsis which thoroughly mixes the juice with the food, and in the thin-walled intestine absorption of the digested material takes place. ”

“ Second, The gastric juice; secreted in the inner or third lining of the stomach,—an acid, and powerful enough to dissolve all the fiber and albumen of flesh food.
Third, The pancreatic juice; secreted by the pancreas, which you know in animals as sweetbreads. This juice has a peculiar influence upon fats, which remain unchanged by saliva and gastric juice; and not until dissolved by pancreatic juice, and made into what chemists call an emulsion, can they be absorbed into the system.
Fourth, The bile; which no physiologist as yet thoroughly understands. ”

“ Once in the stomach, chewed food has to be churned in order to mix it with hydrochloric acid, pepsin, and other digestive enzymes. Manufacturing these enzymes is also considerable work! Churning is even harder work than chewing but normally, people are unaware of its happening. While the stomach is churning (like a washing machine) a large portion of the blood supply is redirected from the muscles in the extremities to the stomach and intestines to aid in this process. ”

“ There are, however, scattered throughout the skin, and also throughout the lining of the digestive tract, a number of specially modified epithelial cells, which are no doubt delicate organs of sense. They are provided at their free extremity with a long hair, and are prolonged on their inner side into fine processes which penetrate into the deeper part of the epithelial layer of the skin or digestive wall. They eventually join a fine network of protoplasmic fibres which forms a special layer immediately within the epithelium. ”

“ Ptisan, then, appears to me to be justly preferred before all the other preparations from grain in these diseases, and I commend those who made this choice, for the mucilage of it is smooth, consistent, pleasant, lubricant, moderately diluent, quenches thirst if this be required, and has no astringency; gives no trouble nor swells up in the bowels, for in the boiling it swells up as much as it naturally can. ”

“ The food over and over again is brought into closest contact with the intestinal walls by the swift kneading movement of the muscles. Thereby not only is the undigested food intimately mixed with the digestive juices, but the digested food is thoroughly exposed to the organs of absorption. Mall has shown that contraction of the intestinal wall has the effect of pumping the blood from the submucous venous plexus into the radicles of the superior mesenteric vein, and thus materially aids the intestinal circulation. ”

“ If one, however, mixes with the condensed foods named above a good proportion of cereals, fruits and vegetables, all of which possess a considerable percentage of undigestible material, the presence of this undigestible material in the intestines leads to strong peristaltic movements, causing the passage of this material along the intestinal tract to the rectum, which will be periodically evacuated. In such cereal foods as the coarser meals (like oatmeal, various wheat preparations and corn meal) , the proportion of bran substance serves as a local stimulation to the intestinal activity. ”

“ Then, lest haply a stomach, unaccustomed to the new and highly concentrated materials, should, as is not improbable, find itself unequal to the task of digesting and absorbing them, a portion of gastric juice, borrowed for the occasion, mostly from the pig, is associated therewith to meet, if possible, that difficulty, and so to introduce the nourishment by hook or by crook into the system. ”

“ Not only is this the case with the secretion from the glands surrounding the mouth, but the pancreas which is concerned in a later stage of digestion is a gland so similar to the salivary glands that in ordinary cookery both are dressed and served as ‘sweetbreads;’ the ‘pancreatic juice’ is a liquid closely resembling saliva, and contains a similar diastase, or substance that converts starch into dextrin, and from dextrin to sugar. ”