The digestibility of different substances we considered under the article Aliment, and we there spoke from observation, assuming, as the criterion, the exacerbation of hectic paroxysms, which always occurs during digestion, and is greater in proportion to the difficult solubility of the food. Constitutions, however, greatly differ in this respect; and we ought to add, that the opinions of other authors differ from our own. We shall, therefore, adduce the conclusions of a respectable observer, M. Gosse, of Geneva, who, by swallowing air, was at any time able to discharge the contents of the stomach. His experiments are recorded in Spalan-zani's work; but, that we may not be suspected of distorting them to favour our own ideas, we shall transcribe the account from a late respectable, but unequal, publication.

"He informs us, that in about an hour and a half after the food is taken into the stomach, it is changed into a pultaceous mass; the gastric juice, likewise, renders it fluid, without altering its nature; and when digestion is properly carried on, there is no appearance of acidity or alkalescence; the food does not ferment; and the process of digestion is not completed until the space of between two and three hours has elapsed.

"The chyme which arises from aliments taken either from the animal or vegetable kingdom is the same; they both are, by the gastric fluid, converted into the same substance, which is in consequence most probably of their both containing gelatine, etc. If, however, the digesting solvent is not in sufficient quantity, or is in a diseased state, the acetous fermentation will take place in vegetable, and the putrid in animal, matter; hence milk, vegetable matter containing sugar, wine, and even spirits, will degenerate, when left to their spontaneous changes in the stomach, to a very strong acid, and sooner sometimes than out of the body, perhaps from the heat, etc. All oily substances likewise become rancid, and flesh meat putrid, producing acid and putrid eructations, Which is never the case in a state of healthy digestion; whilst, in many animals, the digestion is finished before the acetous or putrid fermentation can begin.

"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. Indurated white of egg.

"Vegetable substances.

"1. Oily or emulsive seeds. 2. Expressed oils of different nuts and kernels. 3. Dried grapes, and the skins offish. 4. Rind of farinaceous substances. 5. Pods of beans and peas. 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. It does not destroy the life of some seeds; hence bitter-sweet, hemp, misletoe, and other plants which sometimes grow upon trees, arc produced by the means of the excrements of birds, the kernels of the seeds being defended from the menstruum by their 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.

"Vegetable substances.

"1. Salads of different kinds rendered more so when dressed. 2. White of cabbage, less soluble than red. 3. Beet, cardoons, onions, and leeks. 4. Roots of scurvy grass, red and yellow carrots, succory, 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 pastry, from their producing acidity. 7. Fresh and dry figs. By frying all the substances in butter or oil they become less soluble. If they are not dissolved in the stomach, they arc, 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, arc sooner dissolved than that of old. 2. Fresh eggs. 3. Cow's 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 ornitho-galus 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 Arabians use it as food.

"Substances which facilitated the menstrual power of the gastric juice are, sea salt, spices, mustard, scurvy grass, horse radish, radish, capers, wine, spirits in small quantities, cheese, particularly when old, sugar, various bitters.

"Substances which retarded the gastric power are, water, particularly hot, and taken in large quantities. It occasions the food to pass into the intestines without being properly dissolved. All acids, astringents, 24 grains of Peruvian bark, taken half an hour after dinner, stopped digestion. All unctuous substances, ker-mes, corrosive sublimate. Gosse likewise observed, that employment after a meal suspended or retarded digestion, as well as leaning with the breast against the table; and that repose of mind, vertical position, and gentle exercise, facilitated it."

See Fordyce on Digestion; Richerand's Elements of Physiology; Senebier's Observations (Journal de Physique, Mars, 1785); Carminiati's Experiments, ibid, vol. xxvi.; Spalanzani's Tracts; Brugnatelli Sagio d'un Analisi Chimica de succi Gastrici; Steven's Thesis; Gosse's Experiments.