Substances insoluble, or that were not digested in the usual time in the stomach. Animal substances : 1. Tendinous parts. 2. Bones. 3. Oily or fatty parts. 4. In durated white of egg. Vegetable sub stances : 1. Oily or emulsive seeds. 2. Expressed oils of different nuts and ker nels. 3. Dried grapes, and the skins of fish. 4. Rind of farinaceous substances. 5. Pods of beans and pease. 6. Skins of stone fruits. 7. Husks of fruits with grains or seeds. 8. Capsules of fruit with grains. 9. Ligneous stones of fruits. 10. The gastric juice does not destroy the life of some seeds ; hence bitter-sweet, hemp, misletoe, and other plants which sometimes grow upon trees, are produc ed by the means of the excrements of birds, the kernels of the seeds being de fended from the menstruum by exterior covering. Substances partly soluble, or parts of which were digested. Animal substances : 1. Pork dressed various ways. 2. Black puddings. 3. Fritters of eggs, fried eggs and bacon. Vegeta ble substances : 1. Salads of different kinds, rendered more so when dressed.
2. White of cabbage, less soluble than red. 3. Beet, cardeons, onions, and leeks.
4. Roots of scurvy grass, red and yellow carrots, are more insoluble in the form of salad than any other way.
5. The pulp of fruit with seeds, when not fluid. 6. Warm bread, and sweet pas try, from their producing acidity. 7. Fresh and dry figs. By frying all the substances in butter or oil they become still less soluble. If they are not dissolv ed in the stomach, they are, however, in the course of their passage through the intestines. Substances soluble or easy of digestion, and which are reduced to a pulp in an hour, or an hour and a half. Animal substances : 1. Veal, lamb, and in general the flesh of young animals, are sooner dissolved than that of old. 2. Fresh eggs. 3. Cows' milk. 4. Perch boiled with a little salt and parsley ; when fried or seasoned with oil, wine, and white sauce, it is not so soluble. Vegetable substances : 1. Herbs, as spinach, mixed with sorrel, are less soluble ; celery, tops of asparagus, hops, and the ornithogalus of the Pyrenees. 2. Bottom of artichokes.
3. Boiled pulp of fruits, seasoned with sugar. 4. Pulp or meal of farinaceous seeds. 5. Different sorts of wheaten bread, without butter, the second day after baking, the crust more so than the crumb, salted bread of Geneva more so than that of Paris without salt ; brown bread, in proportion as it contains more bran, is less soluble. 6. Rapes, turnips, potatoes, parsnips not too old. 7. Gum arabic ; but its acid is soon felt : the Ara bians use it as food. Substances which facilitate the menstrual power of the gas tric juice are, sea-salt, spices, mustard, scurvy grass, horse radish, radish, ca pers, wine, spirits in small quantities, cheese, particularly when old, sugar, various bitters. Substances which retard the gastric power are water, particularly hot, and taken in large quantities. It oc casions the food to pass into the intes tines without being properly dissolved. All acids, astringents, twenty-four grains of Peruvian bark, taken half an hour after dinner, stop digestion. All unctu ous substances, kerrnes, corrosive subli mate.
Gosse likewise observed, that employ ment after a meal suspended or retarded digestion, as well as leaning with the', breast against a table ; and that repose of mind, vertical position, and gentle exer- t cise, facilitate it. It likewise appears, that from the soluble power of this fluid digestion goes on after death, but it is far less considerable than in the living , animal ; that in fishes it retains its pro perty of digesting flesh, but in an infe rior degree to that of birds ; and that in some animals heat is necessary to this power, which acts independent of the vi tal power.
Hunter attributes to the action of the gastric juice, the erosions found in the stomachs of those who have died sudden ly, in which sometimes the great curva ture of that organ is entirely consumed ; he often found them on opening dead bo dies ; the edges of the wounds appearing like half-digested food.
Such is the stupendous power of that fluid which is perpetually secreting by the stomach in a state of health, in order to comminute and dissolve into a pul taceous mass the alimentary substances which are introduced into it. Here, how ever, the action of the gastric juice, and perhaps of the stomach itself, ceases: for whatever is found in the stomach is chyme, or this pultaceous and uniform mass alone. We have no chyle, except by regurgitation from the smaller intes tines. The stomach is therefore altoge ther a preparatory organ and it appears to be the action of the different fluids se creted from the collatitious viscera, the saliva, the pancreatic juice, and the bile, (we confine ourselves to the more per feet animals) that are alone able to con vert this comminuted chyme into the saccharine fluid, called chyle, as it de scends through the pylorus, or inferior orifice of the stomach, into the duodenum, in which the process of chylification is chiefly performed, and amidst the folds or valvulte connivente8 of which the lac teals are most numerously seated.
Yet it is not every thing the stomach is capable of dissolving, that the secondary action of the chylopoletic viscera is capa ble of converting into food, or of convert ing with equal facility; nor is it every sub. stance, as we have already seen, contain ing the real principle of aliment, that the stomach itself is capable of dissolving in the same period of time, or with the same degree of ease.
Hence the necessity of attending to what we have made the second branch in our present tract on dietetics, the nature of different alimentary 'substances, and: especially of the common principle on which the aliment of all them may per haps depend.
Regarding this subject on a compre hensive scale, we have much reason to suppose that there is no substance what, ever, either in animal, vegetable, or mi neral existence, but contains a basis, from which some animal or other is capable of extracting nutriment. Nor is this much to be wondered at, since we have already observed, that in different classes of ani mals the organs of digestion vary in every possible manner, in regard to their pre sence or deficiency; and more especially since we knoW that the fluid secreted by the stomach itself, the only organ that is universal, is equally discrepant in its powers and qualities in animals of differ ent structure ; being in some naturally acid, in others alkaline, and in others again insipid or neutral. And hence we not only discern the truth, but can trace the real cause of the fact long ago ob served by Lucretius, iv. 640.
Tantaque in Nis rebus distantia, differitus gue est, lit, quad aids cibus est, allis fuat acre vole rum.
So vast, at times, The strange discordance, that which poisons this, To that proves healthful, and proton gates life."