AUTOLYSIS IN PATHOLOGICAL PROCESSES 93 



than does a sterile infarct, and by comparing the rate of soften- 

 ing in septic and aseptic iufarcts we see that the cellular autol- 

 ysis is a very slow process as compared to the heterolysis 

 accomplished by the leucocytes. The explanation of this may 

 lie in the fact that most intracellular proteases act best in an acid 

 medium (Wiener), while leucocytic proteases act best in an alkaline 

 medium (Opie), and the infarcts of small size are seeped through 

 by alkaline blood fluids. When an infarct is large, we find it 

 undergoing central softening while the periphery remains firm ; 

 this corroborates our hypothesis, for acids are developed during 

 autolysis (Magnus-Levy), which at the periphery are neutralized 

 by the blood plasma, so that only at the center is autolysis 

 active. The inhibiting action of the serum also has a similar 

 effect, limiting autolysis at the periphery. 



In the case of septic softening the action of the bacteria 

 needs also to be taken into consideration, since they also pro- 

 duce proteolytic ferments, but their effect seems to be relatively 

 small as compared with leucocytic digestion. Intracellular 

 digestion of necrotic tissue by leucocytes seems also to be rela- 

 tively unimportant. Suppuration, therefore, must be considered 

 as the result of digestion of dead tissue by enzymes derived 

 from the leucocytes, the plasma, the bacteria, and the destroyed 

 cells themselves. A tubercle does not ordinarily suppurate, 

 because the tubercle bacillus and the substances it produces are 

 not strongly chemotactic, and hence not enough leucocytes enter 

 the necrotic area to produce a digestive softening. The enzymes 

 of staphylococcus are much more strongly proteolytic than 

 those of streptococcus (Knapp l ), which may be one reason 

 why the latter so much more frequently produces lesions with- 

 out suppuration than does the former. Necrotic areas of any 

 kind are absorbed by similar processes. Autolysis of tumors 

 is quite active in specimens removed from the body, and the 

 areas of necrosis that occur commonly in tumors are absorbed 

 in this way. Apparently all varieties of cells are subject to 

 autolysis or heterolysis whenever they are killed or sufficiently 

 injured. Atrophy may be looked upon as an autolysis in the 

 normal course of catabolism, not met by a corresponding build- 

 ing up of the proteids. 



The products of autolysis may of themselves be toxic ; albu- 

 moses and peptones certainly are, and the other cleavage products 

 are probably not altogether innocuous. (See "Autointoxication. ") 

 Some of the symptoms of suppuration, particularly the fever 

 and chills, have been ascribed to the autolytic products rather 



1 Zeit. f. Heilk. (Chir.), 1902 (23), 236. 



