﻿STUDIES IN PLAGUE IMMUNITY. 257 



instance extracellular and cultures of the abdominal exudate on agar produced 

 a rich growth of bacteria. In further experiments on rats, where strains of 

 different pathogenetic power were employed, the very virulent strains were taken 

 up by the phagocytes through the action of the immune serum, while avirulent 

 strains (those non-lethal in doses of 2 oesen) became dissolved in the abdominal 

 cavity of the animal without the aid of the phagocytes. Strains of moderate 

 virulence became partially destroyed by both of these means. The same mechanism 

 was observed in passive immunization with serum, as was seen in animals actively 

 immunized, either with killed or with living attenuated cultures. 



Kolle "" in December, 1904, on pursuing further experiments of this nature, 

 confirmed Markl's results. He also compared the method of action of plague, 

 cholera and typhoid immune sera, testing the bactericidal action of plague 

 serum in vitro after the method of Neisser and Wechsberg. He was unable to 

 demonstrate any bactericidal reaction, in spite of the many variations in the 

 experiments and the use of many different sera to supply the complement for 

 the completion of the action of the amboceptors. Plague bacilli after treatment 

 with the immune serum developed as plentifully in the culture media as they did 

 in those instances in which they were treated with normal serum. Kolle and 

 Hetsch employed fresh, normal serum from the pigeon, cow, horse, chicken, rabbit, 

 donkey, 'and rat for supplying the complement. Upon investigating the question 

 of whether the bacterial receptors of the plague bacillus were able to bind ambocep- 

 tors in an immune serum, it was shown that such a binding did actually take place, 

 and that the serum after being first treated with living plague bacilli lost in anti- 

 infectious power, as was shown by experiments performed on rats. How _ ever, at 

 the temperature of the ice box or when killed pest bacilli were substituted for 

 living ones, binding of the amboceptors could not be demonstrated. Moreover, the 

 union did not occur under the same quantitative relations as it does with typhoid 

 and cholera immune serum. Kolle therefore concluded that the pest serum acts 

 neither as a pure antitoxic serum, such as we see in diphtheria and tetanus, nor 

 as a pure bactericidal one, such as we see in cholera and typhoid. 



Skschrvan 70 also obtained Pfeiffer's phenomenon in guinea pigs which were 

 inoculated with 4 cubic centimeters of the Paris pest serum and sixteen to twenty 

 hours later reinoculated with from 2 oesen to 1 agar culture intraperitoneally. 

 When the serum was inoculated into the peritoneum, the bacteria became broken 

 up in one-half hour. The control animals without serum died after one to two 

 days while those inoculated with immune serum lived for from Ave to seven days. 

 In the latter instance, in three cases, a periorchitis existed and the omentum 

 was shrunken and hard. 



In 1902, Wright and Windsor 71 showed that normal human serum was entirely 

 without bactericidal action upon the pest bacillus and that sterilized cultures of 

 this organism were not capable of abstracting a bactericidal element from such 

 blood. In the following year Wright and Douglas T - further showed that, while 

 no bactericidal reaction was exerted against the plague bacillus by normal human 

 serum, such serum evidenced a distinct opsonic action against this organism. 

 On the other hand Row " maintained that the serum of plague convalescents 

 possessed remarkable bactericidal properties. He found that while in hanging. 



69 Ztschr. f. Byg. u. Infectionskraiilh., Leipz. (1904), 48, 371. 



70 Centrbl. f. Bakteriol. Orig. (1903), 33, 271. 



71 J. of Byg. (1902), 2, 385. 



72 Proc. Roy. Soc. Lond. (1904), 73, 130. 



73 Brit. Med. Journ. (1902), 1895. 



