﻿186 STRONG. 



cent) succumbed to pest infection. Twenty-seven control animals were 

 also inoculated at the same time in the same manner; these all died of pest. 

 Twelve animals in Series 44 (p. 232) were inoculated with exudates 

 obtained from the guinea pigs comprising Series 43. The immunity 

 of the animals was tested about one month after the first inoculation; 

 eight (66.6 per cent) died and four (33.3 per cent) were found to 

 be immune. 



5. IMMUNIZATION OF ANIMALS BY KLEIN'S METHOD. 



Only a few guinea pigs were inoculated with the prophylactic prepared 

 after the method of Klein because it did not seem clear that it possessed 

 any advantages over immunization with the aggressin exudates, while it 

 appeared to cause more local irritation. Thirteen guinea pigs in Series 

 54 (p. 232) and 56 (p. 233) were each inoculated with a portion of the 

 powder dissolved in 2 cubic centimeters of saline solution and obtained 

 from dying at 46 c to 4?° C. and then triturating in a mortar the buboes, 

 spleen, liver and lungs of guinea pigs which had died of subacute pest 

 infection. Sloughs of the skin followed the inoculations in five in- 

 stances. The immunity of the animals was tested with the virulent 

 pest strain about one month after the first inoculation, when all but 

 four (30 per cent) succumbed to pest infection. 



Klein does not refer to a marked local reaction following the injection 

 of his prophylactic, and perhaps such a reaction was in his experiments 

 avoided by some details in the manufacture of the prophylactic not 

 emphasized in his preliminary description of its preparation. 



