STARVATION 107 



would be fully digested in the ordinary course of events. Oppenheimer 

 and Aron (309) think that something more than the mere presence of 

 an " anti-trypsin " is involved in this resistance of normal serum. In 

 support of this contention they quote the observations of Schwartz 

 (367). This worker held that protein was resistant because of a 

 peculiar combination of aldehyde groups in the protein molecule 

 which offered but few points of attack for the enzyme. Fischer has 

 also shown in another connexion that a certain degree of specificity 

 of formation in the substrate can exist, and of course it is possible 

 that such an explanation may be the correct one here. It may be 

 that the proteins under certain unnatural conditions become so 

 altered that they are open to the attack of enzymes to which at 

 other times they are immune. Until, however, our knowledge of the 

 nature and constitution of the protein molecule is more intimate it is 

 useless to speculate with any degree of certainty along such lines as 

 these. 



As regards the presence of the proteolytic enzymes in tissues, it 

 was first pointed out by Salkowski (351) that fresh tissues kept (anti- 

 septically) at body temperature slowly dissolved, and the protein was 

 replaced by various amino acids. To this change he gave the name 

 of auto-digestion. Jacoby (211) carried these investigations further. 

 He showed that a variety of the known decomposition products of 

 protein could be detected in the liquefied tissue and that the change 

 took place much more rapidly under aseptic conditions. He gave 

 the name of autolysis to the process of disintegration. Hedin and 

 Rowland (178) and Hedin (176) were able to demonstrate the presence 

 of proteolytic enzymes in juices expressed under high pressure from 

 various tissues and organs. Further, Hedin found more than one 

 form of autolytic enzyme in the spleen. Vernon (406) has also 

 proved the presence of an erepsin-like ferment in the tissues. Finally 

 Leathes (246), Dakin (106) and Cathcart (88), using the most 

 modern methods, have shown that the various amino acids formed in 

 the process of autolysis are apparently identical with those produced 

 by the action of the true digestive ferments. 



Abderhalden and Prym (25) have demonstrated that the liberation 

 of the different amino acids during the progress of autolysis is only 

 gradual ; even after fifty days' autolysis a fair amount of the products 

 are present in a more complex form. Abderhalden and Lussana (27) 

 have further shown that the expressed juices from different tissues 

 can decompose various polypeptides. Recently Abderhalden and his 

 pupils (50) have introduced some new polariscopic methods for the 



