﻿IX. THE BACTERICIDAL ACTION' OF PLAGUE SERUM. 



The German Plague Commission concluded that in pest immune sera 

 specific bactericidal anti-bodies were present, the action of which was 

 fully analogous to that of the protective substances which had been 

 demonstrated by E. Pfeiffer to exist in cholera and typhoid infection. 

 However, they made no experiments which demonstrated that such sera 

 possessed a bactericidal action against the pest bacillus, although some 

 experiments were performed which demonstrated their preventive action 

 against infection and their curative value. Nevertheless, the opinion that 

 plague immune serum exerts a bactericidal action against this organism 

 apparently became generally accepted, although but little experimental 

 work was carried on upon the subject. 



In 1902, Kolle and Martini 07 performed experiments with guinea pigs and rats 

 in which the animals were inoculated with from 1 to 2 cubic centimeters of pest 

 immune serum and after twenty-four hours were inoculated intraperitoneally with 

 from 2 to 3 oesen of pest cultures of moderate virulence, suspended in saline 

 solution. Three or four hours after the inoculation of the bacteria, upon 

 microscopical examination according to the method of Pfeiffer, of drops of the 

 exudate from the abdominal cavity, the majority of the bacilli were found to be 

 swollen, degenerated, and broken up. This phenomenon was not noted in control 

 animals treated with normal serum, but pest bacilli of normal appearance were 

 observed, which increased in number from hour to hour up to the time of the 

 death of the animal. The abdominal exudate of the animals injected with 

 immune serum was sometimes apparently sterile after twenty-four hours, although 

 in these eases the few remaining bacteria usually multiplied and caused the death 

 of the animal at a later time. Animals, such as rats, which had been actively 

 immunized against pest by repeated subcutaneous injections of living, attenuated 

 cultures, when injected intraperitoneally with pest strains of moderate virulence 

 also exhibited the same bactericidal action toward the bacteria, but no anti-toxic 

 action could be observed. 



Markl ^ as a result of his observations found that the process of destruction of 

 pest bacilli varied according to the virulence of the organism. When a culture 

 of very great virulence was inoculated into the abdominal cavity of a guinea 

 pig which had been treated with an immune serum, after thirty minutes a very 

 extensive leukocytosis occurred and the bacteria were taken up by the phagocytes. 

 Those bacteria which remained free, became agglutinated and grouped about the 

 leucocytes. One hour after the injection of the immune serum he could find 

 no extracellular bacilli in the peritoneal exudate and cultures made from it 

 either remained sterile or developed only a few colonies. A leucocytosis also 

 occurred in control animals without immune serum, but the bacilli remained in this 



"Deutsche med. Wchnsch. (1902), 28, 45. 

 w Ztschr. f. llijg. u. InfectionshrankK., Leipz. (1903), 42, 244. 

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