74 THE ROYAL SOCIETY OF CANADA 



as a matter of fact, it is always very much greater, and (2) if the 

 nitrogen of the butyl-soluble and mono-amino fractions be added 

 together, the sum, at every stage except the first day, is greater than 

 the total mono-amino nitrogen (34.9) to be expected even after 

 complete hydrolysis. It would seem, therefore, that in the main 

 at least the butyl-soluble fraction must be a real product of tryptic 

 digestion. I hope to be able in future work to improve the technique 

 of the extraction so that the amino nitrogen of the digest will be 

 completely recovered; if this can be done the uncertainty just dis- 

 cussed will disappear. 



Department of Biochemistry, 

 University of Toronto. 



