AUTOLYSIS IN PATHOLOGICAL PROCESSES 97 



were found to undergo alterations only after several weeks, 

 and then as the result of the action upon them of invad- 

 ing leucocytes. The slow rate of autolysis that occurs in 

 infarcts and other aseptic areas is presumably due to the action 

 of the antibodies of the serum, for it was found, experimentally, 

 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, finally accomplished by 

 the leucocytes acting from the periphery, there being little 

 actual autolysis of the dead cells by their own enzymes. The 

 rapidity 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 convo- 

 luted tubules) ; (2) spleen, pancreas ; (3) kidney (collecting 

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

 bronchial epithelium) ; (5) thyroid ; (6) myocardium ; (7) vol- 

 untary 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 autol- 

 ysis and heterolysis. 



Degenerated nervous tissue also undergoes a slow autolysis 

 which, according to Noll, 1 results in the splitting of protagon 

 with liberation of lecithin. Mott, Halliburton, 2 Donath, and 

 others have shown that in nerve destruction lecithin is split up 

 with liberation of cholin (see " Cholin " ). Koch and Goodson 3 

 found that degenerated nervous tissue is characterized, chemi- 

 cally, by containing a relatively increased amount of nucleo- 

 proteids, with an absolute decrease in solid constituents, while 

 the lecithans are greatly altered. 



In caseation autolysis is very slight, as is shown by the per- 

 sistence of the caseous material for long periods of time without 

 absorption. Presumably the toxin of tuberculosis destroys the 

 autolytic ferments of the cells it kills, and as there is little 

 chemotactic influence, leucocytes do not enter the caseous area. 

 Spiethoff 4 found that pure caseous material is usually free from 

 even traces of albumose and peptone, but the caseous material 

 at the periphery mixed with tissue elements contains them in 

 very small quantities, suggesting that at the periphery of 



1 Zeit. physiol. Chem., 1899 (27), 390. 



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

 8 Amer. Jour. Physiol., 1906 (15), 272. 



4 Cent. f. inn. Med., 1904 (25), 481. 



