166 PAPAIN-PROTEOLYSIS. 



solution or pancreatic juice, on the other hand, the formation 

 of peptone is much greater, although the hemipeptone formed 

 is eventually broken down by the continued action of the 

 enzyme into amido-acids, etc., leaving only the antipeptone. 

 If papain is a true peptone-forming enzyme, related more 

 closely to trypsin than to pepsin, it follows that under favor- 

 able circumstances it might be expected to produce even more 

 than 50 per cent of peptone. It is not to be understood by 

 this statement that papain can be compared with trypsin in 

 rapidity of action ; but merely that of the proteid dissolved 

 by papain, under suitable conditions, fully 50 per cent might 

 not unreasonably be looked upon as convertible into true 

 peptone by the continued action of the enzyme. The correct- 

 ness of this view has been tested by several series of quanti- 

 tative experiments in which the proportion of proteoses and 

 peptones formed has been determined as accurately as existing 

 methods will allow. 



The first experiment, of this nature may be described as 

 follows: Coagulated egg-albumin, formed by pouring the 

 whites of eggs into boiling water acidified with acetic acid, 

 was washed thoroughly with water, pressed, and finely divided. 

 The content of dry albumin was then determined in a sampled 

 portion by drying at 110 C., and igniting the residue to 

 obtain the amount of ash. By this method 10 grams of the 

 moist coagulum were found to contain 1.9257 grams of dry 

 proteid. Three digestive mixtures were then prepared, each 

 containing 150 c.c. of 0.25 per cent sodium carbonate satu- 

 rated with chloroform, 50 grams of the moist coagulated 

 albumin and 0.75 gram of active papain. To obviate any 

 error that might be introduced through the presence of albu- 

 mose, etc., in the papain, a fourth mixture was prepared 

 similar to the above, except that it contained no albumin. 

 All four mixtures were placed in closely stoppered flasks and 

 transferred to a warm chamber, where they were kept at 

 38-40 C. for varying lengths of tune with occasional agita- 

 tion. One was allowed to digest for 25 hours, the second was 

 interrupted at the end of 51 hours, while the third mixture 



