90 ENZYMES 



".why the stomach does not digest itself/ 7 and the answer that 

 satisfies some is that dead protoplasm is essentially different 

 from living protoplasm. More exact replies are suggested by 

 Wiener's studies on the relation of the reaction of the tissues 

 to their autolysis. He found that autolysis does not begin in 

 an organ until the original alkalinity is neutralized by the acids 

 which are formed in all dead and dying cells. 1 If enough alkali 

 is added to the material from time to time to neutralize the 

 acidity as it develops, autolysis does not take place. Abundant 

 amounts of organic acids are formed in autolysis of the tissues, 

 principally lactic, acetic, and butyric (Magnus-Levy), 2 and the 

 latent period between the time of the removal of an organ from 

 the body and the appearance of autolysis may be explained by 

 the time required for the neutralization of alkalescence. The 

 old observation that rigor mortis disappears most rapidly in 

 muscles that have been exhausted just before death is also prob- 

 ably explained by the greater amount of acid in such muscles. 3 

 If we imagine that autolysis is limited to periods when the cells 

 have an acid reaction, however, we limit their range of useful- 

 ness in the living cell to a minimum, since during life the tissue 

 fluids, and presumably the cell contents, are preponderatingly 

 alkaline. Perhaps a better explanation of the attack of the 

 cells by their own enzymes after death is to be sought in the 

 conditions of chemical equilibrium. During life constant new 

 supplies of proteid are being brought to the cell, and at the 

 same time the products of proteolysis are presumably being 

 carried away by the circulation or being changed by oxidative 

 processes. When circulation stops, the processes of splitting go 

 on without the introduction of new supplies of material, and 

 hence the tissues are not replaced as fast as they are destroyed, 

 and the products of their decomposition accumulate, for lack of 

 any means of destroying or removing them. 



Still another possible defense of the living cells may be found 

 in the existence of specific antienzymes. Just as the serum 

 contains antitrypsin, so it seems to contain substances antag- 

 onistic to the autolytic enzymes. Levene and Stookey 4 found 

 that tissue juices show a resistance to digestion, and Opie 5 

 found that the serum of inflammatory exudates retarded the 



1 Opie (loc. cit.) found, however, that autolysis of leucocytes was more rapid 

 in an alkaline medium. 



2 Hofmeister's Beitr., 1902 (2), 261. 



3 Delrez (Arch, internat. de Physiol., 1904 (1), 152) found by cryoscopic 

 methods that muscle undergoes rapid autolysis during the first seven to nine 

 hours after its removal from the body ; after this the rate is much slower. 



4 Jour. Med. Kesearch., 1903 (10), 217. 



5 Jour, of Exp. Med., 1905 (7), 316. 



