PHOSPHORUS FROM CASEINOGEN. 



451 



Papain, thus, exerts its greatest action on caseinogen in a neutral or 

 faintly acid medium, and resembles trypsin more than pepsin with 

 regard to the amounts of P 2 5 and N converted into a soluble state. In 

 alkaline media, even in 0*2 per cent. Na-jCOi solution, the action was 

 very slow, and resembled pepsin, but was more rapid. The results do 

 not agree with those of the previous observers, but can be easily 

 explained by the difference in the method employed. Their methods 

 were to obtain acid or alkali albuminate on neutralisation, or to observe 

 the solution of fibrin under the action of papain, methods which give 

 no true estimate of the amount of action. 



The net result of our experiments is that papain acts best in media 

 which are neutral, or very slightly acid or alkaline; its power of 

 hydrolysing albumins is intermediate between that of pepsin and 

 trypsin; it resembles the latter rather than the former in its rate of 

 dissolving caseinogen and converting it into substances which are not 

 precipitated by tannic acid. 



DIGESTION OF OVOVITELLIN BY TRYPSIN AND BY PEPSIN. 



The digestion of ovovitellin by enzymes has up to the present time 

 been very little investigated. Beyond the facts that ovovitellin is a 

 nucleo-albumin, like caseinogen, and that it leaves a residue of 

 paranuclein on peptic digestion, no observations as to the actual extent 

 of its digestion by ferments have been made. We have therefore studied 



