444 PHYSIOLOGICAL CHEMISTRY. 



that is, the loss of weight of the unit of the weight of the body, 

 namely 1 kilo, is, on the contrary, greater in small animals than in 

 larger ones. The reason for this is that the smaller animals have a 

 greater surface of body in proportion to their mass than larger 

 animals, and the greater loss of heat caused hereby must be replaced 

 by a more active consumption of material (RUBBER). 



Exact observations for a long time are necessary for a thorough 

 study of the exchange of material in starvation. As these have 

 seldom been made on man our knowledge of the exchange of 

 material in starvation has been gained by observations on animals, 

 especially on carnivora. 



As the exchange of material in starvation takes place at the 

 expense of the constituents of the body, it must take place in 

 essentially the same way in both carnivora and herbivora. As the 

 food of the herbivora is ordinarily richer in carbohydrates and non- 

 nitrogenized nutritive bodies than that of the carnivora, so in star- 

 vation the body of the herbivora becomes relatively richer in 

 proteids. On this account the elimination of urea is increased in 

 herbivora in the first part of the period of starvation. In carniv- 

 ora the elimination of urea decreases, as a rule, immediately at the 

 beginning of the starvation, and in the later periods only small 

 amounts of urea are voided by herbivora as well as by carnivora. 



The extent of the metabolism of proteids and the elimination of 

 urea, which is a measure for the same, does not show in carnivora 

 any uniform decrease during the entire period of starvation. 

 During the first few days the elimination of nitrogen is greatest 

 and the quantity of the same depends essentially upon the amount 

 of proteids in the organism and the nature of the food previously 

 taken. The richer the body is in proteids from the food previously 

 taken the greater is the metabolism of proteids, or, in other words, 

 the elimination of nitrogen during the first days of starvation is 

 greater. The rapidity with which the elimination of nitrogen 

 decreases in the first days depends also, according to VOIT, upon 

 the proteid condition of the body. It decreases more quickly, 

 that is, the curve of the decrease is more sudden, the first days of 

 starvation, as a rule, the richer the food was in proteids which was 

 taken before starvation. This condition is apparent from the fol- 

 lowing table. This table contains three different starvation experi- 



