61 



During an eight-day period they give to a dog 1866.7 gm. of meat 

 of the above-mentioned constitution, together with 27.4 gm. of fat. In 

 the urine and feces of this period they find 62.36 gm. of nitrogen, which 

 would correspond to a destruction of 387.09 gm. of dry flesh or 1695.5 

 gm. of living tissue of the dog. 



The balance would therefore read: 



Grams 



Flesh destroyed 1695.5 



Flesh ingested 1866.7 



Flesh retained 171.2 



Add fat retained . . 27.4 



Total maximum assimilation 198.6 



The gain in body weight was 337 gm., the excess was attributable to 

 water retention. 



Not only was the elementary composition of the urine and feces de- 

 termined (as in the method of Boussingault), but on seven different occa- 

 sions the carbon dioxid in the respiration was determined in periods 

 lasting one hour each. After this fashion Bidder and Schmidt were able 

 to estimate the quantity of the carbon metabolism, which they express 

 as follows: 



C in 

 grams 



387.09 gm. of muscle metabolized contain 205.20 



In the excreta were eliminated 194.02 



Retained in the body 11.08 



Since the total carbon elimination in the urine, feces and respiration 

 was less than that derivable from the flesh metabolized, it was evident 

 that the ingested fat could not have participated in the metabolic process, 

 but must have been absorbed and stored in the body. Analysis of the 

 feces showed the almost complete absorption of fat. 



This method of determining the total metabolism is in principle that 

 used by Pettenkofer and Voit a decade later. 



The authors strike the following balance, showing the fate of 100 gm. 



of meat protein : 



C H N O S 



100 gm. meat protein 53.01 7.02 16.11 22.86 1.00 



In 34.52 gm. urea 6.91 2.30 16.11 9.20 



In 65.48 gm. rest for respiration 



and bile production 46.10 4.72 13.66 1.00 



