SECT. 9] 



PROTEIN METABOLISM 



1 109 



were noticeable in the ammonia nitrogen, the humin nitrogen, and 

 in the non-amino nitrogen in the phosphotungstic filtrate. These are 

 unexplained. Within the di-amino fraction the arginine, lysine and 

 cystine rose, while the histidine fell, some of which changes agree 

 with those found for the chick, and some of which do not. 



Table 150. Gortnef s figures for Cryptobranchus allegheniensis. 



% of the total nitrogen 



Ether-soluble fraction 



Undeveloped 1 

 Ammonia nitrogen ... ... 0-048 



Humin nitrogen ... ... ... 0191 



Basic (di-amino) nitrogen ... 0-048 



Non-basic (mono-amino) nitrogen 0-114 



Hatching larvae 



o-io8 Rise 



Rise 



5-256 



86-52 



Gortner unfortunately did not make analyses for urea and uric 

 acid by direct methods, and their presence or absence has therefore 

 to be discussed on the basis of their probable solubilities under his 

 special conditions. Although it is always stated that uric acid is 

 insoluble in ether and alcohol, and that urea is insoluble in ether, 

 Gortner affirmed that in continuous extraction this was not the case, 

 and that appreciable quantities of these substances would pass out 

 into the extracting liquid. Although he did not fully prove this point, 

 his main conclusion rests upon it. If the urea and uric acid were not 

 passing out into the ether and alcohol, they were remaining behind 

 masked in the "protein" fraction, so that it would not be surprising 

 if by these methods no urea production could be demonstrated. As 

 Gortner hydrolysed all his fractions, the urea and uric acid nitrogen 



