AUTOLYSIS ].\ JWTIIOIAHIKAL I' HOC ESSES 85 



rhythmical chaiijic of tliis nalui'c might be imajiiiicd as occuniMg and 

 accounting for interaction by the enzymes, particiihirly since; rliythmi- 

 cal changes in metabolism are known to occur {e. g.,) rhythmical pro- 

 duction of carbon dioxide (Lyon^^), and enzyme action in vitro may 

 show rhythmic variations (Groll).^'* 



Autolysis in Pathological Processes 



All absor];)tion of dead or injured tissues, and of organic foreign 

 bodies, seems to be accomplished by means of digestion by the enzymes 

 of the cells and tissue fluids. We may distinguish between the diges- 

 tion brought about bj^ the enzymes of the digested tissue itself, or 

 autolysis, and digestion by enzymes from other cells or tissue fluids, 

 or hetcrolysis (Jacoby). Heterolysis is accomplished particularly by 

 the lecucocytes, which contain ferments capable of digesting not only 

 leucocytic proteins but apparentlj^ every other sort,^'' from serum- 

 albumin to catgut ligatures. The heterolysis may be intracellular 

 when the material to be digested has first been taken up by the cells 

 (phagocytosis); or extra-cellular, either by enzymes normally con- 

 tained in the blood plasma and tissue fluids, or by enzymes liberated 

 by the leucocytes and fixed tissue cells. On death and dissolution of 

 a cell the intracellular enzymes are released, ^^ but it is not known to 

 what extent the enzymes may be secreted from intact living cells. As 

 far as pathological processes show, the amount of liberation of en- 

 Z3'mes from normal cells is very slight, if any, and the digestive en- 

 zymes of the blood plasma seem to be very feeble, but this is perhaps 

 because they are largely held in check by the anti-enzymatic substances 

 of the serum. Pathological autolysis and heterolysis, therefore, are 

 brought about chieflj'^ bj' enzymes liberated from dead or injured cells. 

 Bacteria, however, can multiply upon a medium of coagulated protein, 

 which suggests that they also secrete proteolytic substances. In 

 pathological conditions digestion of degenerated tissues seems usuallj'^ 

 to be the result of both autolysis and heterolysis. An infarct softens 

 because the intracellular enzymes digest the dead cells, exactly as 



«^ Science, 1904 (19), 350. 



8^ Nederl. Tijdschr. v. Geneesk., 1918 (1), 1085. 



8^ Manj^ authors suggest that the leucocytes merely carry enzymes from one 

 organ, particularly the pancreas, to another, and that these enzymes are not 

 formed by the leucocyte itself. Opie (Jour. Exp. Med., 1905 (7), 759) has shown, 

 however, that the bone-marrow contains proteolytic enzymes which are like those 

 of the leucocytes in that they act best in an alkaline medium, whereas the auto- 

 lytic enzymes of the lymphatic glands and most other tissues act best in an acid 

 medium. This leaves little room for doubt that the leucocj'tes are equipped 

 with their characteristics enzjmies when they leave the bone-marrow, and that 

 they are not obtained later in the pancreas or elsewhere. More recently, however, 

 van Calcar (Pfliiger's Archiv., 1912 (148), 257) has revived the idea of the origin of 

 leucocj'tic enzymes in the digestive glands. 



8^ Peptolytic enzymes appear in the urine after severe superficial burning, pre- 

 sumably coming from the disintegrated cells. (Pfeiffer, Miinch. med. ^^'och., 

 1914 (61), 1329.) 



