388 RETROGRESSIVE CHANGES 



who first described a reaction based on this observation, considers 

 that the substance is a pentose,*^ derived from the nucleoproteins of the 

 pancreas; it bears no relation to the fat necrosis, but is commonly 

 found with fat necrosis because of the associated pancreatitis. Pre- 

 sumably cell necrosis elsewhere than in the pancreas may at times 

 cause the same reaction to appear/ In pancreatitis with fat necrosis, 

 or whenever there is any injury to the pancreas, there may be found 

 an increase in the amount of diastase in the blood and urine, sufficient 

 to be of diagnostic value according to Y. Noguchi.'^^ The peritoneal 

 exudate in acute pancreatitis is not toxic, contains no free trypsin and 

 is no more lipolytic than normal serum, presumably because of neu- 

 tralization of the enzymes and poisons by the exuded plasma.'" 



Self -digestion of the pancreas occurs soon after death, and the pan- 

 creatic juice may in this way bring about a portmortem fat digestion 

 that resembles somewhat the intravital fat necrosis in its gross ap- 

 pearances,® and Wells found that the same changes might be pro- 

 duced by injecting pancreatin into the bodies of dead animals, or 

 by keeping fat tissue in pancreatin solutions. Wulff found that fatty 

 acids were demonstrable by Benda's method in the pancreas of nearly 

 all cadavers. The process differs from the intra vitam form in being 

 less sharply circumscribed, and microscopically by the absence of cellu- 

 lar and vascular reaction. That the essential changes of fat necrosis 

 can be produced postmortem is final proof that they are due to 

 enzymes, rather than to circulatory or cellular action. 



GANGRENE 



This term indicates merely that certain marked secondary changes, 

 either putrefaction or desiccation, have occurred in necrotic areas of 

 some size. Hence we have the chemical changes of putrefaction 

 added to those of necrosis in the case of moist gangrene, whereas in 

 dry gangrene nearly all the chemical changes are brought to a stand- 

 still through the desiccation. In the latter it is only at the line of 

 demarcation, where some moisture remains, that chemical changes 

 still go on ; these consist chiefly of autolysis of the dead tissues, and 

 also of their digestion by leucocytes, which results eventually in the 

 separation of the dead tissue from the living; this is best seen after 

 surface burns, carbolic-acid gangrene, etc. 



Moist gangrene is accompanied by the dual action of the cellular 

 enzymes and of the putrefactive organisms that are growing in the 



c Weber believes that it is a liexose (Dent. med. Wocli., ini2 (3S), 106). and 

 it may be urinary dextrin (Pekelliaring and Van IToo>renhuyze, Zeit. phvsiol. 

 Chem." 1014 (91),' 151). 



7 See Wliipple, et al, Johns Hopkins TIosp. ■Bull.. 1010 (-21). XV.) -. Karas. Zeit. 

 klin. Med., 1013 (77). 125. 



7a Arch. klin. C'hir., 1012 (OS). TT. 2. 



7b Whipple and Coodpastiire, Siir";.. Gvn. and OI)st.. lOi;? (17), 541. 



sChiari, Zeit. f. Ileilk., 180(1 (17), 00 ;" Pforrinjrer, Virehow's Arch.. ISOO (15S), 

 126; Liepmann, ibid., 1002 (100), 532; WulfT, Bcrl. klin. Woch., 1002 (30), 734. 



