ENZYMES. 43 



have been called catalases. Also reduction processes will be mentioned 

 which seem to be brought about by enzymes. 



Besides these processes just mentioned the following processes, 

 namely, autolysis and putrefaction, are to be considered as due to enzyme 

 action entirely or in part. 



If an animal organ is kept in water at 37 C. under conditions so 

 that no micro-organisms are active then the organ gradually dissolves 

 in great part under the influence of the contained enzymes. This 

 process is called autodigestion or autolysis. The action of micro- 

 organisms can be prevented either by removing the organ under strictly 

 aseptic conditions or by allowing the digestion to take place in the 

 presence of antiseptic substances (toluene, chloroform, etc.). As the 

 animal organs consist chiefly of protein substances the autolysis con- 

 sists chiefly in the action of enzymes which dissolve proteins. Autol- 

 ysis was first observed and studied by SALKOWSKI and his pupils 

 with liver, muscle and supra-renal capsule. 1 JACOBY then showed 

 that the enzymes active in autolysis do not orginate in the digest- 

 ive tract and are not identical with trypsin or pepsin. 2 BIONDI found 

 that hydrochloric acid had a favorable influence upon the autolysis 

 of the liver while HEDIN and ROWLAND 3 observed that the organic 

 acids accelerate the autolysis of nearly all organs. This has been sub- 

 stantiated by several authors (WIENER, AniNKiN 4 ). The findings of 

 LANE-CLAYPTON and SCHRYVER S that the autolysis of the liver and 

 kidneys begins only after a latent period of from two to four hours 

 when the post mortem formation of acid is at its height, substantiates 

 the influence of the acid reaction. 



The autolysis is retarded to a great extent by an alkaline reaction. 

 This is shown by the experiments of SCHWIENIG with the liver as well 

 as those of HEDIN and ROWLAND with several other organs. HEDIN 

 has also shown by experiments with various organs that a preliminary 

 treatment with acetic acid markedly helps the autolysis in alkaline reac- 

 tion, which for the spleen at least is explained by a destruction through 

 the treatment of acetic acid of a substance which has an inhibiting action 

 in alkaline solution. Such an inhibiting substance destroyed by acetic 



1 Zeitschr. f . klin. Med., 1890, Suppl., Schwiening, Virchow's Arch., 136, 444 (1894), 

 Biondi, ibid, 144, 373 (1896). 



2 A complete summary of the literature of intracellular enzymes and autolysis may 

 be found in Jacoby, Ueber die Bedeutung der intrazellularen Fermente, etc., Ergeb- 

 nisse der Physiologie, Jahrg. 1, Abt. 1, 1902. 



3 Zeitschr. f. physiol. chem., 32, 341, 531 (1901). 



4 Wiener, Centralbl. f. Physiol., 19, 349 (1905); Arinkin, Zeitschr. f. physiol. Chem., 

 53, 192 (1907). 



6 Journ. of Physiol., 31, 169 (1904). 



