338 BACTERIOLYSINS 



Custom, however, has never strictly differentiated between the two 

 terms, and bacteriolysis appears to be but a continuation of and a more 

 nearly complete bactericidal process. Hence the definition just given 

 covers both terms bacteriolysins and bactericidins. 



Origin of Bacteriolysins. Our knowledge regarding the origin of the 

 bacteriolysins is quite fragmentary. The investigations of Pfeiffer and 

 Marx in cholera, and Wassermann in typhoid, have shown that the 

 spleen and hematopoietic organs in general may be especially concerned. 



According to Metchnikoff, the " bacterial fixateurs," which are 

 practically the bacteriolysins, are secretory or excretory products of 

 phagocytic cells, especially the polynuclear leukocytes or microphages. 

 It is commonly believed that during infection the bacteria cause phag- 

 olysis or disintegration of these cells, with liberation of both comple- 

 ments (cytases) and amboceptors (fixateurs), which produce extracellu- 

 lar lysis of the invading bacterium (bacteriolysis). If, on the other 

 hand, the phagocytes are fortified and phagolysis is prevented, the bac- 

 teria are phagocytized and undergo intracellular lysis, a condition that, 

 according to Metchnikoff, may be induced experimentally by giving an 

 animal an intraperitoneal injection of sterile bouillon twenty-four hours 

 before bacteria or other cells are injected. 



That leukocytes afford a bacteriolytic substance is supported by ob- 

 servations showing that leukocytic exudates, secured by the injection 

 of a sterile aleuronat suspension, possess a well-marked germicidal ac- 

 tivity. Issseff found that the intraperitoneal injection of sterile bouillon 

 and other mild irritants, by producing a leukocytic exudate that supplied 

 certain bactericidal substances and facilitated phagocytosis, increased 

 the resistance of animals to bacterial infection. At one time surgeons 

 made practical use of this observation by injecting nucleinic acid and 

 other substances into the peritoneal cavity before performing laparot- 

 omy, in order to induce a local resistance to a possible infection. 



LEUKINS AND LEUKOCYTIC EXTRACTS 



The bactericidal substance contained within leukocytes has been ex- 

 tensively studied by Schattenfroh, Schneider, Peterson, Hiss and 

 Zinsser, Manwaring, and others. It has been observed that when leu- 

 kocytes are suspended in diluted blood-serum, the bactericidal proper- 

 ties of the serum are increased without coincident destruction of the 

 cells, showing that the leukocytes may secrete germicidal substances into 

 the fluid. The same observation has been made with Bier's congestive 



