Among the circumstances which affect the digestibility and nutrient power of meats are the age at which the animals eaten were killed, and the care bestowed upon them in feeding, shelter, and transportation. Animals which have been underfed, ill-treated, and worried yield very inferior meat.

Almost all meat is tougher immediately after killing, and improves on being kept for a day or two. Violent exercise is believed to increase the tenderness of the meat of hunted animals.

In general, the flesh of young is more digestible than that of old animals, provided they are not still suckling.

It would be convenient if meats and animal foods of all kinds could be arranged in a table of comparative digestibility, but such tables are necessarily inaccurate, if not actually misleading, owing to the great variations produced by the character of the particular samples of food used, by the time and manner of cooking, by the condition of the digestive organs, and by personal idiosyncrasy. No two tables of this kind given by different authors are found to agree in all respects.

The following table is offered as an average of the ease of digestibility of animal foods, the time required for the completion of gastric digestion being the chief standard, but some foods may be well enough digested although they require half an hour or so longer time than others.

Table Of Comparative Digestibility

(Commencing with the Most Digestible, and ending with the Least Digestible of Meats and Other Common Animal Foods')

Oysters.

Soft-cooked eggs. Sweetbread.

White fish, boiled or broiled, such as bluefish, shad, red snapper, weakfish, smelt. Chicken, boiled or broiled. Lean roast beef or beefsteak. Eggs, scrambled, omelette. Mutton, roasted or boiled. Squab, partridge. Bacon (crisp).

Roast fowl, chicken, capon, turkey. Tripe, brains, liver.

Roast lamb.

Chops, mutton or lamb.

Corned beef.

Veal.

Ham.

Duck, snipe, venison, rabbit, and other game.

Salmon, mackerel, herring.

Roast goose.

Lobsters and crabs.

Pork.

Smoked, dried, or pickled fish and meats in general.

The table given below is published by E. Jessen as the result of giving test meals of single articles of food. The stomach was first cleansed and emptied by siphonage, then a hundred grains of meat were introduced with eight ounces of water. Samples of the digested stomach contents were from time to time withdrawn, and the complete disappearance of all muscular fibre when examined by the microscope occurred as follows:

Beef, raw, chopped fine................................... 2 hours.

Beef, half cooked......................................... 2 "

Beef, well cooked......................................... 3 "

Beef, thoroughly roasted.................................. 4 "

Mutton, raw............................................. 2 "

Veal, cooked............................................. 2 "

Pork, cooked............................................ 3 "

These estimates fall somewhat below those of other writers, and for comparison he gives the time for digestion of six hundred cubic centimetres of raw cow's and goat's milk as three and a half hours, and that of boiled milk as four hours, which is too long.