AUTOLYSIS IN NECROTIC TISSUES 93 



the cause of the h).ss of nueleai- staining so characteristic of necrosis. 

 That these changes are due to the intracellular enzymes was shown by 

 implanting in animals pieces of sterile tissues, the enzymes of which 

 had been destroyed by heating; these were found to undergo altera- 

 tions only after several weeks, and then as the result of the action 

 upon them of invading leucocytes. The slow rate of autolysis that 

 occurs in infarcts and other aseptic areas is presumably due in part to 

 the action of the antibodies of the serum, for it was found, experimen- 

 tally, that the histological changes of autolysis when the tissues are 

 placed in heated serum proceed about twice as rapidly as when they 

 are placed in fresh serum. Chemotactic substances do not seem to 

 be formed in aseptic dead tissues, but the slow absorption of such 

 tissues is, however, finalh^ accomplished by the leucocytes acting 

 from the periphery, there being little actual autolysis of the dead 

 cells b}' their own enzj'mes. The rapidit}' with which autolytic 

 changes occur in different organs, as indicated by the disappearance 

 of nuclear staining, seems to be about as follows: (1) Liver, kidney 

 (epithelium of convoluted tubules); (2) spleen, pancreas; (3) kidney 

 (collecting tubules, straight tubules, glomerules); (4) lung (alveolar 

 and bronchial epithelium); (5) thyroid; (6) myocardium; (7) volun- 

 tary muscle; (8) skin (epithelium); (9) brain (cortical cells). Stroma 

 cells seem to be attacked chiefly by enzymes from the parenchyma 

 cells. Of all cellular elements, the endothelium of the vessels seems 

 to have the greatest resistance to both autolysis and heterolysis. 



The finer structural changes of aseptic autolysis of liver in salt so- 

 lution, have been carefuly studied by Launoy,^^ who notes a period 

 of relative latency (20 to 24 hours at 38°) , followed by rapid changes 

 in both cytoplasm and nucleus, associated with the appearance of 

 myelin forms. Dyson^^ describes loss of the Altmann's granules in 

 autolyzing cells. Cruickshank*" states that when aseptic autolysis 

 of tissues kept in a moist chamber is observed microscopically the 

 changes are slower, and there is less solution of the cytoplasm, but in 

 general the results are much the same. No. fat could be found by 

 special stains. Fetuses that have undergone aseptic autolysis in the 

 uterus show complete loss of nuclei in 5 to 6 days, a stage correspond- 

 ing to 8 to 15 days autolysis in the moist chamber. In experimental 

 nephritis Simons^^ observed a decreased autolysis of the kidneys. 



Degenerated nervous tissue also undergoes a slow autolj^sis which, 

 according to Noll,*^ results in the splitting of "protagon" with hbera- 

 tion of lecithin. ]\Iott, Halliburton, ■'•^ Donath, and others have shown 



'* Ann. Inst. Pasteur, 1909 (23), 1. 



"9 Jour. Path, and Bact., 1912 (17), 12; also Aschoff, Verb. deut. Path. Gesellsch, 

 1914 (17), 109. 



" Jour. Path, and Bact., 1911 (16), 167. 



"Biochem. Zeit., 1S14 (67), 483. 



" Zeit. physiol. Cheiu., 1899 (27), 390. 



*^ General resume in Ergebnisse der Physiol., 1904 (4), 24. 



