FOOD AND DIGESTION. 327 



pork, 10; beef is also firmer, more satisfying, and is supposed to be 

 more strengthening than mutton, whereas the latter is more digestible. 

 The flesh of young animals, such as lamb and veal, is less digestible and 

 less nutritious. Pork is comparatively indigestible, and contains a 

 large amount of fat. 



Flesh contains: (1) Nitrogenous bodies; chiefly myosin, and one or 

 more globulins; serum-albumin, gelatin (from the interstitial fibrous 

 connective tissue); elastin (from the elastic tissue), as well as hcemo- 

 globin. (2) Fatty matters, including lecithin and cholesterin. (3) Ex- 

 tractive matters, some of which are agreeable to the palate, e.g. osmazome, 

 and others, which are weakly stimulating, e.g., creatin. Besides, there 

 are sarcolactic and inositic acids, taurin, xanthin, and others. (4) Salts, 

 chiefly of potassium, calcium, and magnesium. (5) Water, the amount 

 of which varies from 15 per cent in dried bacon to 39 in pork, 51 to 53 

 in fat beef and mutton, to 72 per cent in lean beef and mutton. (6) A 

 certain amount of carbo-hydrate material is found in the flesh of some 

 animals, in the form of inosiie, dextrin, grape sugar, and (in young 

 animals) glycogen. 



PORK, AND VEAL. 



Fats. Salts. 



3.6 5.1 



29.8 4.4 



4.9 4.8 



31.1 3.5 



15.8 4.7 



48.9 2.3 



Together with the flesh of the above-mentioned animals, that of the 

 deer, hare, rabbit, and birds, constituting venison, game, and poultry, 

 should be added as taking part in the supply of nitrogenous substances, 

 and alsofah salmon, eels, etc., and shell-fish, e.g., lobster, crab, mussels, 

 oysters, shrimps, scollops, cockles, etc. 



TABLE OF PERCENTAGE COMPOSITION OF POULTRY AND FISH. (LETHEBY.) 



Water. Proteid. Fats. Salts. 

 Poultry . ; . ..*.-. . 74 21 3.8 1.2 



(Singularly devoid of fat, and is therefore generally eaten with bacon 

 or pork.) 



Water. Proteid. Fats. Salts. 



White Fish . . .. . ; 78 18.1 2.9 1. 



Salmon . . 77 16.1 5.5 1.4 



Eels (very rich in fat) 75 9.9 13.8 1.3 



Oysters . . , . 75.74 11.72 2.42 2.73 



(7.39 consist of non-nitrogenous matter and loss.) (Payen.) 

 Even now the list of fleshy foods is not complete, as the flesh of 

 nearly all animals has been occasionally eaten, and we may presume 



