Liqiuiactiun-Xccrosis: Moist Goiii^rcnc. i8l 



tents of a "residual abscess," etc. The moist cheesy matter is the 

 well known "pyoid" material of "cold abscesses." In dry casea- 

 tion calcification is apt to occur as a terminal change.] 



Necrosis with softening, liquefaction-necrosis. Necrosing tissues 

 which are poor in coagulable albuminates but rich in fat and fatty 

 substances, and w^hich contain considerable fluid or are in position 

 to obtain it from the entrance of lymph, usually break down into a 

 soft pulpy mass or into a milk-like emulsion. The process may 

 occur as a primary one, as in the brain and cord, because of the 

 large amount of myelin contained by these parts (as also 

 seen in infarcts and haemorrhagic effusions) ; or it may occur 

 as a secondary change where an originally coagulated necrotic sub- 

 stance becomes macerated after fatty degeneration or saturation 

 with serous fluid, or is softened by the liquefying products of 

 various bacteria (soft caseation, purulent softening). [The type 

 of liquefaction here described is essentially the same mentioned 

 by the editor under the name of moist caseation in the last note. 

 There is a form of liquefaction however in which the fatty elements 

 mentioned by the author are absent or at least not important, the 

 necrotic tissues becoming converted into a clear, watery fluid. This 

 resultant fluid may in a greater or less measure be the product of 

 actual conversion of the solid substance into liquid ; in part it is 

 made up of lymph, which has penetrated the part. The disappear- 

 ance of the solid substance may be a mere solution of the soluble 

 portions in the absorbed fluid, but in addition the insoluble portions 

 may be rendered soluble or changed into fluid by the influence of 

 poisons (often bacterial), heat or cold or by enzymes originating 

 in the necrotic tissue itself or generated by the surrounding living 

 cells or by microorganisms present in the mass. Such material 

 is apt to be removed from the affected part, usually by absorption, 

 or may be retained within a capsule as a cyst.] 



Necrosis with putrefaction, moist or putrid necrosis, gangrene 

 (^ Tct^ipaiva ) , Sphacelus (6 cr0dKe\os from <T<pd^€Lv , to kill), phagcdccna 

 (r, <t>a-yi^aLva) . Whcu uccrotic tissuc rich in fluid is open to access 

 of putrefactive bacteria a putrid decomposition sets in precisely as 

 in case of a piece of meat or a cadaver. The gangrenous area is 

 soft, pultaceous, filthy, dark brown to green or dark red in color, 

 stinking and permeated by putrid gases. The putrefactive bacteria 

 gain entrance from the surrounding air to the softened part through 

 lesions (from wounds or ulcers) of its protective covering (epi- 

 derm, skin) or from the canals lined by mucous membrane, upon 



