CH. XXVIII.] 



MEAT AND FLOUR. 



463 



not eaten ; in some cases this is a matter of fashion, in others, 

 owing to an unpleasant taste, such as the flesh of carnivora is 

 said to have ; and in other cases (e.g. the horse) because it is more 

 lucrative to use the animal as a beast of burden. 



Meat is the most concentrated and most easily assimilable 

 of nitrogenous foods. It is our chief source of nitrogen. Its 

 chief solid constituent is proteid, and the principal proteid is 

 myosin. In addition to the extractives and salts contained 

 in muscle, there is always a certain percentage of fat, even 

 though all visible adipose tissue is dissected off. The fat-cells 

 are placed between the muscular fibres, and the amount of fat so 

 situated varies in different animals ; it is particularly abundant 

 in pork ; hence the indigestibility of this form of flesh : the fat 

 prevents the gastric juice from obtaining ready access to the 

 muscular fibres. 



The following table gives the chief substances in some of the 

 principal meats used as food : 



The large percentage of water in meat should be particularly 

 noted ; if a man wished to take his daily minimum of 100 

 grammes of proteid entirely in the form of meat, it would be 

 necessary for him to consume about 500 grammes (i.e., a little 

 more than lib.) of meat per diem. 



Flour. 



The best wheat flour is made from the interior of wheat grains, 

 and contains the greater proportion of the starch of the grain and 

 most of the proteid. Whole flour is made from the whole grain 

 minus the husk, and thus contains not only the white interior but 

 also the harder and browner outer portion of the grain. This 

 outer region contains a somewhat larger proportion of the proteids 

 of the grain. Whole flour contains i to 2 per cent, more proteid 



* The flesh of young animals is richer in gelatin than that of old : thus, 

 looo parts of beef yield 6, of veal 50, parts of gelatin. 



