COMPOSITION OF ANIMAL BODIES 373 



498. Influence of Food upon the Composition of Ani- 

 mal Bodies. The nature of the food consumed has a 

 noticeable effect upon the composition of the animal body. 

 The food affects both the amount of meat produced and 

 its composition. As a general rule, an unbalanced ration, 

 particularly one with a large amount of non-nitrogenous 

 compounds, produces flesh that is poor in circulatory pro- 

 teids. But few systematic experiments have been made 

 to study the influence of food upon the composition of 

 animal bodies. 



499. Composition of the Human Body. Halliburton 

 states that the human body contains 58. 5 per cent, water. 

 The amount at different stages of life varies; in later life, 

 the body contains less than during youth. Water is 

 present in all parts of the body ; enamel contains 2 per 

 cent., the gray matter of the brain 85 to 86 percent., 

 bone about 50 per cent. , and muscle 75 per cent. The 

 amount of fat varies between quite wide limits; normally, 

 Moleschott states that it makes up from 4 to 5 per cent, 

 of the weight of the body. Adipose tissue contains about 

 85, marrow 96, and nerves 22 per cent. fat. Twenty- 

 five percent, of the muscle is solid matter, of which 21 

 per cent, is proteid and albuminoid material, and 4 per 

 cent, is fat and nitrogenous extractive bodies. Mineral 

 matter is present in small amounts combined with the 

 muscular and other tissues and in solution in the various 

 fluids and secretions. 



