84 . ENZYMES 



highly probable that serum cheeks autolysis at least in part by virtue 

 of its "buffer" function, which interferes with the development of 

 acidity. Lack of oxygen cannot be held solely responsible for auto- 

 lysis, according to the stuches of Morse, ^^ who found that autolysis 

 occurs in muscles with divided nerves but intact blood supply. Never- 

 theless, reduced blood supply results in increased H-ion concentration 

 which greatly facilitates autolysis, and it cannot be denied that auto- 

 lysis is observed chiefly if not solely in asphyxiated tissues. 



There can be no question that the supply of food-stuff is of essential 

 importance in determining autolytic changes, for it has been found 

 by Conradi,^^ Rettger,^'' and Effront'* that bacteria and yeasts begin 

 to undergo autolysis when they are placed in distilled water or salt 

 solution, which they do not do, to any such extent at least, when in 

 nutrient media. (In this way it has been found possible to obtain 

 the intracellular poisons of such bacteria as tj^phoid and cholera.) 

 Autolysis is not marked so long as the bacteria are supplied with 

 nourishment, but when nutrient material is lacking, autolytic decom- 

 position is no longer repaired and the bacteria disintegrate. Pre- 

 sumably the changes are the same in tissue cells, and anemic necrosis 

 may be explained in this wa}'. Tissue enzymes are also capable of 

 digesting bacteria (Turro^^). 



Another direction in which the key to the action of these enzymes 

 may be sought has been indicated by Jacoby,^*^ who found that to a 

 certain degree the autolytic enzymes of each organ are specific for that 

 organ. Liver extract will not split lung tissue, although it will split 

 the proteoses that are formed in lung autolysis, possibly because these 

 proteoses are less specific than the proteins from which they arise, or 

 perhaps because of the erepsin the extract contains (Vernon). Leuco- 

 cytic proteases, however, seem capable of splitting foreign proteins 

 of all sorts. Richet^^ states that the protease of liver tissue does 

 not attack either muscle tissue or liver tissue that has been coagulated. 

 Another hypothesis has been advanced by Fermi,*- who suggests 

 that the protoplasm of living cells is not digested because its structural 

 configuration is such that the enzymes cannot unite with it, an attract- 

 ive but practically undemonstrable idea. 



Lastly, it must be considered that at least to some extent the en- 

 zymes exist in the cells in their inactive zymogen form, and per- 

 haps are changed into the active form as needed, and inhibited or 

 changed back again wlien their work is temporarily finished. A 



" Amer. Jour. Phvsiol., lUlf) (liO), 147. 

 '» Deut. mod. Woi-li., l<)():} (2«)), 20. 

 "Jour. Med. Hcsciiroh. n)04 (Ui), 79. 

 '8 Bull. Soc. Cliiiii., HH).") (;};{), 847. 

 '»Cont. f. Bakt., 1902 (:V2), 105. 

 »« llofineistcr's Boitr., 190:} (;}), 440. 

 8' (Joiiipt. Boiul. Soc. Biol., 190:} {'•>'■>), tiot). 

 82 Cent. 1'. Bakl., 1910 (■>(>), .1."). 



