472 



METABOLISM, NUTRITION, AND DIET 



Numerous imvestigations are in progress which may demonstrate more 

 fully the specific influence of phosphorus on animal nutrition and on 

 growth. Tunnicliff has demonstrated that an increase of the phosphorus 

 content of the food of children, if given in complex organic form, increases 

 the efficiency of the metabolism of nitrogen by as much as 10 per cent. 

 If given to children as calcium phosphate it has no beneficial influence 

 in this regard. Forbes, in his experiments on the nutrition of pigs, shows 

 that the individuals fed with food to which phosphorus was added, as ground 

 fresh bone, grew larger and stronger skeletons, but that the presence of 

 organic phosphorous (phytin) led to the greatest general growth. 



PERCENTAGE OP PHOSPHORIC ACID (P 2 O 6 ) IN SOME FRESH FOODS. (QUOTED 



FROM GlRARD, BY HuTCHINSON, IN "FOOD AND DIETETICS.") 



Vegetable. Per cent. 



Carrot 0.036 



Turnip o . o 58 



Cabbage o . 089 



Potato o . 140 



Chestnuts o . 200 



Barley meal o . 230 



Animal. Per cent. 



Pork o.i 60 



Milk 0.220 



Beef 0.285 



Eggs 0.337 



White cheese -374 



Mutton 0.425 



Salts in the body not only take part in the reactions themselves, but they 

 stimulate in other substances reactions that are of incalculable benefit to 

 the body. 



The necessity for the taking of water in order to balance the daily ex- 

 cretion, is sufficiently obvious. Man will live only a few days if deprived of 

 water. 



Effects of Deprivation of Food. The animal body deprived of all 

 food dies from starvation in the course of a variable time. The length of 

 time that any given animal will live in such a condition depends upon many 

 circumstances, the chief of which are the nature and activity of the metab- 

 olism of its tissues. 



The effect of starvation on the lower animals is, first of all, as might be 

 expected, a loss of weight. The loss is greatest at the beginning of the dep- 

 rivation period, but afterward decreases to a level from which it does not 

 vary much day by day until death ensues. Chossat found that the ultimate 

 proportional loss in different animals experimented on was almost exactly 

 the same, death occurring when the body had lost 40 per cent, of its original 

 weight. Different parts of the body lose weight in very different proportions. 

 The following most noteworthy losses are taken, in round numbers, from 

 the table given by Chossat: 



