\.\nn:T/i:s of xecrosis 383 



have a coagulation of tissue proteins associated with the deposition 

 of considorahle quantities of fat, the reason for the gross roseniljhince 

 of the pro(hic't of tliis form of necrosis to cheese is ai)i)arent. 

 Schmoll '* has analyzed caseous nuiterial, and found it almost en- 

 tirely free from soluble proteins or proteoses. The protein material 

 is almost solely coagulated protein, which in its elementary composi- 

 tion is related to the simple proteins or to fibrin, and not at all to 

 the luicleoproteins. The extremely small amount of phosphorus pres- 

 ent in the caseous material indicates that the products of disintegra- 

 tion of the cell nuclei must diffuse out earh^ in the process. Casea- 

 tion is, therefore, characterized by a coagulation of the proteins and 

 a dissolving out of the nuclear components. SchmoU does not ex- 

 plain the cause of coagulation, however. It may be that it is the 

 same as in the coagulation of anemic infarcts (since tuberculous areas 

 are decidedly anemic), or possibly the tubercle bacillus produces sub- 

 stances coagulating proteins, as Ruppel states is the property of 

 ' ' tuberculosamin. ' ' Indeed, Auclair ' "' claims that the fatty sub- 

 stance that can be extracted from tubercle bacilli by chloroform is 

 the cause of the caseation. Dead tubercle bacilli do not produce true 

 caseation, however, according to Kelber ; ''^ hence the substance caus- 

 ing the necrosis evidently does not diffuse readily from the bodies of 

 the bacilli. 



The abundance of fat in caseous material is very striking. Bos- 

 sart " found from 13.7 per cent, to 19.4 per cent, of the dry sub- 

 stance of caseous material soluble in alcohol and ether. In the scrap- 

 ings from tuberculous bovine glands I have found 22.7-23.9 per cent, 

 of the organic material soluble in alcohol and ether.'* Of this solu- 

 ble material, Bossart found 25 to 33 per cent, of cholesterol, and 

 Leber '° found 38.31 per cent, of lecithin, which is a much higher 

 proportion than Bossart detected. Presumably these fatty materials 

 are derived chiefl.y from the disintegrated cells; this is probably true 

 of the lecithin and cholesterol, but the fact that in histological prepa- 

 rations most of the fat is found about the periphery of the caseous 

 area,^'^ supports the belief that it has wandered in from the outside. ^^ 

 A certain proportion of the fat is possibly derived from the bodies 

 of the tubercle bacilli, which usually contain about 40 per cent, of 

 fatty matter; but it has not been determined whether the fat from 

 this origin forms an appreciable part of the fatty matter of caseous 

 material. 



'•*Deut. Arch. klin. :\red.. 1004 (81), 163. 



"5 Arcli. med. expi^r.. ISitD, p. .SCi.S. 



78 Quoted by Diirck and Oheriidorfer, Ergebnisse der Pathol., 1800 (0), 288. 



77 Quoted bv Sclimoll, Joe. cif.'i 



78 Wells. -Tour. :\led. Kesearch, 1006 (14), 401. 



79 Quoted bv Solinioll.74 



soSata, Ziejiler's Beitr., 1000 (28). 461. 



81 Fischler and Gross (Zieoler's Beitr., 1005 (7th suppl.), 344) could find no 

 fatty acids in caseous areas by histological metliods. 



