276 IXFLAMMATION, REGENERATION, GROWTH 



SUPPURATION «3 



For the formation of pus two couditions are necessary : ( 1 ) the ac- 

 cumulation of leucocytes, and (2) necrosis and liquefaction of cells 

 and tissue elements. I\Iany leucocytes may be present in a tissue 

 without suppuration ; e. g., erysipelas. Necrosis of cells with their 

 g'radual liquefaction and absorption may also occur without suppura- 

 tion ; e. g., infarcts, aseptic liquefaction necrosis, etc. Hence for sup- 

 puration to occur there must be produced substances with positive 

 ehemotaxis, to cause accumulation of leucocytes, for if a necrotic area 

 is devoid of leucocytes, it does not suppurate: e. g., caseous tubercles. 

 Secondly, necrosis must occur, for digestion and liquefaction of living 

 cells and tissues does not take place. Only substances meeting these 

 requirements — i. e., causing positive ehemotaxis and cell necrosis — 

 will cause suppuration. Therefore, although bacterial infection is 

 the usual cause of suppuration.*'^ it may be produced hy many other 

 substances, among which the following are the best known : Bacterial 

 proteins, even from non-pathogenic bacteria; oil of turpentine, mer- 

 cury, croton oil, silver nitrate solutions (5 to 10 per cent.), and certain 

 vegetable proteins (vegetable "caseins"). 



An excellent example of the importance of leucocytes for suppura- 

 tive softening is the caseous tubercle, which is usually free from 

 leucocytes and does not undergo suppuration. If for any cause leuco- 

 cytes are attracted into the caseous area, softening and pus formation 

 promptly occur. Hence Heile •'■'' found that while pus from a "cold" 

 tuberculosis abscess will not digest fibrin and does not give the biuret 

 reaction, both reactions appear after a leucocytosis has been brought 

 about by injection of iodoform. It was formerly considered that the 

 softening was due to the digestive action of the enzymes of the 

 infecting bacteria, many of which were known to produce digestive 

 enzymes dissolving protein culture-media ; e. g., Staphylococcus pyo- 

 genea. Although to some extent these enzymes may be a factor in 

 causing the softening of the fixed tissues and of the killed leucocytes, 

 their eflPect is probably insignificant as compared with the enzymes 

 liberated by the leucocytes, as shown by tlie production of active 

 experimental suppuration under aseptic conditions with turpentine, 

 croton oil, etc.®® Suppuration is, therefore, the result of three proe- 

 ms inflammatory Exudates, their formation and oomposition. are considered in 

 Chapter xii. 



04 Biieliner considers that liacteria will not ]>rodu('e supjiuration unless they 

 are hroken down so that their pi/ogenic proteins are released: e. (j.. anthrax 

 bacilli cause suppuration when actin^r locally, as in malipnant pustule, hut not 

 when they are causing septicemia, because only in the former case are their 

 pvopenic proteins liberated. 

 '"•""Zcit. klin. Med., 1904 (.'">-)). 508. 

 "" .\j)parently su)iy)iirat ion mav occur in herpes 70ster vesicles in the absence 

 of bacteria, accordin<r tn tlie findinfis of Kreibich (Wien. klin. Woch.. 1001 (14) 

 583 ) . 



