DEFENSE OF CELLS AGAINST A UTOLYTIC ENZYMES 91 



action of the autolytic enzymes that were contained within the 

 leucocytes, and it is possible that continuance of the circulation 

 may provide antibodies to the tissues to hold the intracellular 

 enzymes in check, possibly without interfering with their action 

 on other proteids than those of the cell structure. 



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, 1 Rettger, 2 and Effront 3 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 toxins of 

 such bacteria as typhoid and cholera.) Autolysis is not marked 

 so long as the bacteria are supplied with nourishment, but when 

 nutrient material is lacking, autolytic decomposition is no longer 

 repaired and the bacteria disintegrate. Presumably the changes 

 are the same in living cells, and anemic necrosis may be 

 explained in this way. Tissue enzymes are also capable of 

 digesting bacteria (Turro 4 ). 



Another direction in which the key to the action of these 

 enzymes may be sought has been indicated by Jacoby, 5 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 proteids from which they arise, or perhaps because of the 

 erepsin the extract contains (Vernon). Leucocytic proteases, 

 however, seem capable of splitting foreign proteids of all sorts. 

 Richet 6 states that the protease of liver tissue does not attack 

 either muscle tissue or liver tissue that has been coagulated. 



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

 enzymes exist in the cells in their inactive zymogen form, which 

 perhaps are changed into the active form as needed, and inhib- 

 ited or changed back again when their work is temporarily 

 finished. A rhythmical change of this nature might be imagined 

 as occurring and accounting for interaction by the enzymes, 

 particularly since rhythmical changes in metabolism are known 

 to occur (e. #.,) rhythmical production of carbon dioxide (Lyon 7 ). 



1 Deut. med. Woch., 1903 (29), 26. 



2 Jour. Med. Kesearch, 1904 (13), 79. 

 8 Bull. Soc. Chim., 1905 (33), 847. 



4 Cent. f. Bakt, 1902 (32), 105. 



5 Hofmeister's Beitr., 1903 (3), 446. 



6 Compt. Kend. Soc. Biol., 1903 (55), 656. 



7 Science, 1904 (19), 350. 



