NUTRITION 119 



PERCENTAGE COMPOSITION OF CERTAIN FOODS. 



Generally the animal foods predominate in proteids and 

 fat. Lean beef consists almost entirely of proteid, and can 

 therefore practically be regarded as a pure proteid food. 

 Butter is nearly altogether fat. Of the animal foods we find 

 carbohydrates only in the milk and, in very small quan- 

 tities, in the liver (lactose and glycogen respectively). 



The vegetables chiefly contain the carbohydrates and but 

 little or no fat. Proteids are found in all vegetables, 

 especially in the legumes. 



The following details deserve mention: 



The muscles are called beef. They consist of the muscle fibre 

 proper and connective tissue; the first contains true proteids, the 

 other a substance yielding gelatin. The real proteid value of 

 meat is determined by the proportion of fibres and connective 

 tissue present. 



The amount of fat found in beef varies much and depends upon 

 the feeding. 



The manner of preparation (boiling, roasting, etc.) does not 

 alter the value of beef as a food. Boiled beef (meat from 

 which soup is made) has still the same food value as the red or 

 roasted meat, but is slightly less palatable because the extrac- 

 tives which give it taste have been removed. In beef tea (or 



