RESEARCHES ON CERTAIN PROBLEMS OF PLAGUE IMMUNITY 9 



toxins. Kolle tested various anti-plague sera for antitoxic properties 

 with negative results. He found that normal horse serum possessed the 

 property in some degree, and that the slight toxin-neutralising properties 

 of sera obtained by immunisation did not exceed the limits found in 

 normal serum. 



He attempted to immunise horses by intravenous injection of the 

 primary toxin from young cultures, in others he employed the toxins 

 from old cultures, but in neither case could any antitoxic property be 

 demonstrated in the serum. 



The serum and toxin were mixed, and injected peritoneally. Where 

 4 lethal doses of toxin were employed, 8 rats so treated all died. When 

 2 and 3 lethal doses of toxin were employed, a certain number of rats 

 recovered, even when normal serum was used. Thus, out of i6 rats 

 injected with a mixture of plague serum and toxin, 9 died ; out of 8 

 injected with plague toxin and normal serum, only 5 died. 



Kolle therefore concluded that the toxins found in plague cultures 

 were intracellular toxins, and that consequently, in accordance with a 

 general biological law, their injection into the animal body does not 

 stimulate to antitoxin production. The question of the tenability of 

 this so-called " general biological law " will be discussed later. 



The three following investigations are grouped together because, in 

 all, the toxic or immunising substance, is derived from the animal body. 



Terni and Bandi (1900), proposed to employ, as an anti-plague 

 vaccine, the peritoneal exudate obtained from guinea-pigs and rabbits 

 which had been infected intraperitoneally, and killed during the death 

 agony. The fluid, after being tested to ascertain that it was free from 

 organisms other than the B. pestis, was incubated for 12 hours, and then 

 submitted to a temperature of 50° - 52° C. for two hours. The fluid 

 was brought to a suitable volume by means of a weakly alkaline normal 

 salt solution, containing 0*5 % phenol. The authors claimed that good 

 immunity was obtained, even in 4 to 5 days, and that the injection did not 

 aggravate an already existing infection, but rather tended to prolong 

 life. The blood of an individual who had received an injection of 1-5 to 

 2'5 c.c. showed, within 8 to 10 hours, a hindering influence on the 

 development of the B. pestis. 



Hueppe, F., and Kikuchi, Y. (1905), starting from the work of Bail, 

 Kikuchi and Weil, propose to employ, as an immunising agent, the 



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