470 PHYSIOLOGICAL CHEMISTRY. 



being equal, on the contrary, as above stated in speaking of the 

 exchange of material in starvation, a small individual of the same 

 species of animal, because of its relatively greater surface of body 

 and therefore its relatively greater surface of heat, decomposes 

 relatively more substance. With about the same bodily weight 

 the destruction of proteids is smaller with a greater amount of fat. 

 In women, who generally have less bodily weight and greater 

 amount of fat than men, the consumption of proteids and the 

 metabolism of material in general is therefore smaller, and the 

 latter is ordinarily about ^ of that of men. Otherwise the sex does 

 not seem to hrve any special influence on the exchange of material. 



Young animals have, for the reason above mentioned (page 444), 

 a greater exchange of material than older ones, and they decompose 

 a greater quantity of substance per kilo. In regard to the exchange 

 of material in children the investigations of SCHARLING and FOR- 

 STER on the elimination of carbon dioxide, and of CAMERER on the 

 elimination of urea, are important. 



FORSTER found in children at the ages given and at rest the 

 following elimination of carbon dioxide per kilo in one hour: 



3-5 vears 1.17 grms. CO 3 



6-7" " 1.17 " 



9-13 " , . . . 0.90 " 



In a grown man at rest PETTENKOFER and VOIT found the 

 elimination of carbon dioxide with a mixed diet was 0.55 grm. per 

 kilo in one hour. In children of 3 to 7 years the elimination of 

 C0 2 per kilo is more than double that of grown persons. At the 

 age of 16 years the elimination of carbon dioxide per kilo is about 

 the same as in grown persons. 



CAMERER has found the following results as to the elimination 

 of urea in children : 



TABLE XIV. 



Age. Weight of Body in Kilos. Urea in grms. 



Per Day. Per Kilo. 



7 months 6.50 5.0 0.75 



H years 895 12.1 1.85 



3 



4 



5 



7 



9 



12* 

 15 



1261 11.1 090 



17.43 14.6 0.84 



16.20 12.3 0.76 



18 80 13.9 0.74 



25.10 17.3 0.69 



32 60 17.6 0.54 



35.70 17.9 0.50 



