RECENT WORK ON PROTEIN-HYDROLYSIS 445 



the tissue of the organ, and that it is set free only on the death 

 of the cells. 



Vines also has published some experiments on the peptoclastic 

 powers of pepsin. He used the commercial preparation known 

 as " pepsin, pure scales," as well as a glycerin-extract of the 

 stomach of a pig, and digested fibrin by its aid in o - 2 per cent, 

 solution of hydrochloric acid, employing sometimes no anti- 

 septic, sometimes hydrocyanic acid. He obtained a tryptophane 

 reaction after two days, which became very strong after a 

 further 24 hours. 



When we consider that so many observers have thus 

 obtained evidence of the occurrence of tryptophane when 

 extracts of the stomach have been employed, and when we 

 remember the wide distribution of erepsin in the tissues as 

 shown by Vernon, it does not seem impossible that in these 

 experiments the observers may have been working with mixtures 

 of pepsin and erepsin in various proportions. It is rather 

 singular that Vernon says nothing in his paper on the occurrence 

 of erepsin in the stomach walls, though he has made a very 

 complete examination of most of the other viscera. 



If this view be correct, there seems nothing impossible in 

 the suggestion that the trypsin of the pancreatic juice may also 

 prove to be a mixture of two enzymes ; one of the pepsin class, 

 though differing from gastric pepsin in working in alkaline 

 media, and the other an erepsin, similar to if not identical 

 with Cohnheim's enzyme. This point will doubtless receive 

 investigation in the near future. 



The autolytic digestion of the tissues after death has passed 

 out of the domain of ordinary bacterial putrefaction, and 

 attention may be called to certain agents which play a prominent 

 part in it, and are members of the group of proteoclastic 

 enzymes. The limits of this article forbid more than a passing 

 reference to them ; but no doubt they will throw a light on 

 some features of proteolysis. 



An enzyme of this kind was first suggested by Salkowski 

 in 1890, when he observed that when certain viscera, especially 

 the liver, were crushed and kept at blood heat for a considerable 

 time in presence of antiseptics, the tissue became changed in so 

 far that it yielded an increased amount of nitrogenous substances 

 soluble in water. Several of his pupils have studied these 

 decompositions subsequently, and have found these nitrogenous 



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