The striped is the variety most commonly used as food. Unstriped muscle has a softer texture, but is not so easily masticated as striped, and for this reason may be indigestible. _Tripe_ is composed of the unstriped muscle and connective tissue of the stomach of the cow, and if well cooked forms a cheap and easily digested dish.
_The influence of feeding_ on the quality of the meat is great. In ill-fed or old animals, connective tissue is more abundant, and the meat is tougher. Well-fed and fattened meat contains for equal weights much more nutritious matter than non-fattened meat, the fat which is deposited in the muscle replacing water and not proteid. Hence the gain in nutritive value is an absolute one, and is not attained at the expense of the proteid part of the meat. Young animals, again, contain more water and fat and a larger proportion of connective tissue than the full-grown, and are consequently not so nourishing.
Meat ought to be eaten either before the onset of _rigor mortis_, or near its end, before putrefaction has commenced. During _rigor mortis_ it is denser, tougher, and more difficult to digest than after it.
The proportion of fat in meat varies greatly in different individuals of the same species, in different animals, and in different parts of the same animal. According to Dr. Ed. Smith, the proportion of fat in fat oxen is ⅓, in fat sheep ½, in calves ⅙, lambs ⅓, and fat pigs ½.
Good meat, whether beef or mutton, ought to have a marbled appearance, a medium colour, neither pale pink nor deep purple; its texture should be firm, and not leave the impress of the finger; its odour slight and pleasant, the juice reddish and acid, the bundles of fibres not coarse, and free from foreign particles imbedded in them; and lastly, it should not be taken from an animal killed near the time of parturition, nor in consequence of any accident or disease.
=Beef= is, as a rule, more lean than mutton or pork; it has a closer texture, and more nutritive material in a given bulk. It is also fullest of the red-blood juices, and possesses a richer flavour than the two others.
Liebig’s beef extract contains little if any albumin or gelatin. It is a useful stimulant to the gastric secretion, as in soups at the beginning of a meal, but is not a food. Its chief constituents are the various extractives of meat, the most important of which are inosinic acid, kreatin (C₄H₉N₃O₂,H₂O), and inosite, or muscle sugar (C₆H_{ 12}O₆, 2H₂O). Even in substances like Bovril, containing powdered meat fibre mixed with Liebig’s extract, the amount of nutritive material is very small. The white of one egg contains as much nutritive matter as three teaspoonsful of bovril. None of these substances can be trusted like eggs or milk to keep a patient alive for several weeks.