138 BIO-CHEMICAL JOURNAL 



We see from these numbers, that both the total nitrogen and the 

 residual nitrogen in 150 c.c. of serum, taken from ten different animals, 

 are almost absolutely identical in quantity. We are bound, therefore, 

 to conclude that there is absolutely no evidence that the products of tryptic 

 digestion as such, are circulating in the blood stream. 



The residual nitrogen, except in three or four cases, varies very 

 little from a mean. The variations bear, however, no relation to the 

 state of nutrition. 



We can certainly conclude that it is not the products of tryptic 

 digestion in the serum which exert any influence on the rate of 

 autolysis of the liver. 



The variations in the total nitrogen are influenced chiefly by the 

 hydraemic condition of the blood. When the percentage of total 

 solids is high, the total nitrogen is high, and vice versa. 



The Liver. 



TABLE III 



From this table, it is evident, that so far from the ratio of residual 

 nitrogen to total nitrogen being larger in the case of animals during 

 digestion than in fasting animals, it is smaller. The total nitrogen is 

 also generally larger in fasting animals. There are twt) or three 

 exceptions, as, for example, in the case of animals 17 and 19. It will 

 be noticed, however, that in these two cases, the percentage of total 



