RATIONAL FEEDING OF MEN 389 



cal losses are avoided. In the boiling of meat, there is a 

 decrease in weight of about 30 per cent, due largely to 

 loss of water. About 5 per cent, of proteid matter is 

 extracted, also 13 to 15 per cent, of fat and 51 per cent, 

 of mineral matter. With small pieces of meat, the total 

 loss of weight may be over 50 per cent. The amount 

 of nutrients dissolved varies with the size of the 

 pieces. From experiments made at the University of 

 Illinois, there does not appear to be any great difference 

 in the amount of nutrients extracted from meats by hot 

 or cold water. If the broth is utilized for soup, the nu- 

 trients extracted during cooking are not lost. 



511. Mineral Matter in a Ration. In the calculation 

 of human as well as animal rations, the mineral content 

 of the food is not considered along with the other nutri- 

 ents. This is not because the mineral nutrients are of 

 insignificant value but because nearly all combinations of 

 food contain sufficient, both in amount and variety, for 

 food purposes. Phosphates, compounds of iron, potas- 

 sium and magnesium are required only in comparatively 

 small amounts. It is estimated that with a man at hard 

 labor from 2 to 3.5 grams per day of phosphoric acid are 

 eliminated through the kidneys. Since this includes all 

 of the soluble mineral phosphates of the food, and not all 

 of those are used for functional purposes, it is not neces- 

 sary that the food should contain even 2 to 3.5 grams 

 of available phosphates per day. A ration consisting en- 

 tirely of white bread contains enough phosphates to sup- 

 ply the body and establish a phosphate equilibrium. An 

 average daily ration of mixed foods contains from 5 to 8 



