86 ENZYMES 



they do when the tissue is removed from the body, ground up, and 

 put in the incubator under toluene. In addition leucocytes wander in, 

 disintegrate, and their liberated enzymes help in the process, as also do, 

 to a less degree, the enzymes of the blood plasma. It is because of the 

 heterolysis by leucocytic enzymes that a septic infarct becomes 

 softened so much more rapidly than does a sterile infarct, and by 

 comparing the rate of softening in septic and aseptic infarcts we see 

 that the cellular autolysis 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 inhibit- 

 ing action of the serum also has a similar effect, limiting autolvsis at 

 the periphery. Necrotic areas of any kind are absorbed b}'' similar 

 processes. 



Apparently all varieties of cells are subject to autolysis or heterolysis 

 whenever they are killed or sufficiently injured. Involution of the 

 uterus probably depends upon autolysis, which is much more active 

 in the puerperal uterus (Ferroni^^), and creatine is found in the urine 

 when such autolysis occurs, ^^ although A. Morse^^ considers this to be 

 independent of the uterine autolysis. Atrophy may be looked upon as 

 an autolysis in the normal course of catabolism, not met by a corres- 

 ponding building up of the proteins, but M. IVIorse^^ could find no 

 evidence that the atrophy and involution of the tadpole tail is ac- 

 companied by an accelerated autolysis. The solution of fibrin by 

 tissues, fibrinolysis, is considered to be distinct from tissue autolysis 

 by Fleisher and Loeb.^'' In atrophic cirrhosis the fibrinolytic activity 

 of the blood is increased, which may explain the hemorrhagic tendencj' 

 of this disease. ^^ In the case of septic softening the action of the 

 bacteria needs also to be taken into consideration, since they produce 

 proteolytic ferments, but their effect seems to be relatively small as 

 compared with leucocytic digestion.^- Intracellular digestion of 



*' Arm. di Ostetrica e Ginecol., 1906 (2), 553; see also Sleinons, Bull. Johns 

 Hopkins IIosp., 1914 (25), 195; Arthur Morse, Jour. Amer. Med., Assoc, 1915 

 (05), l()i:i. 



8« Shaffer, Amer. .Jour. Physiol. 1908 (23), 1. 



89 Max Morse, Am. Jour, i'hysiol., 1915 (30), 145. 



90 .Jour. Biol. Chcm., 1915 (21), 477. 



91 Goodi)asture, iiull. .Johns Hopkins JTosp., 1914 (25), 330. 



92 Tlic enzymes of staphylococcus are nmcli more strongly proteolytic tlian those 

 of streptococcals (Knapj), Zeit. f. Heilk. (Chir.), 1902 (23), 230.) which may he 

 one reason why tlie latter so much more frequently produces lesions without suj)- 

 puration tlian does the former. 



