﻿226 



STRONG. 



Sekies 30. — Inoculations with artificial pest aggressin in guinea pigs. 



February 11: The animals of this series were inoculated with Artificial 

 Aggressin I, details of the preparation of which is given in Series 29. The 

 aggressin tested just before inoculation proved to be sterile. The animals were 

 reinoeulated on February 26 by the method described for the guinea pigs in 

 Series 29. (See p. 223.) 



Animal 

 No. 



How inoculated. 



Reinoeulated February 26. 



Result. 



Autopsy and remarks. 



1753 



1754 



4.5 cc. Artificial 

 Aggressin I in- 

 traperitoneally 

 Feb. 11. 



do- 



Abdomen shaved and scari- 

 fied and massaged with 

 portion of spleen of gui- 

 nea pig No. 1768 which 

 died this day of plague. 

 „ do. 



Dead Mar. 

 1, after 13 

 days. 



do _ 



Typical pest buboes. 



Hemorrhagic buboes. 

 Numerous pest bacilli 

 in smears. 









CONTROLS. 



1798 



1799 

 1800 





Abdomen shaved and scari- 

 fied and massaged with 

 portion of spleen of gui- 

 nea pig No. 1768 which 

 died this day of plague. 

 do _ 



Dead Mar. 

 1, after 3 

 days. 



do . 



Pest. Typical buboes. 



Do. 

 Pest bacilli in smears 

 from spleen. 







. . do. . . 



Dead Mar. 

 2, after 4 

 days. 







Series 31. — Inoculations with artificial pest aggressin in guinea pigs. 



May 1 1 : Thirty-six 48-hour, large, agar slant cultures * ( from second genera- 

 tion, guinea pig number 1956) were suspended in 50 cubic centimeters of distilled 

 water. The suspension was then placed on an electrical shaking machine and 

 was thoroughly shaken for three days. On May 14 it was removed and cultures 

 taken which later developed a pure growth of pest bacilli. Five per cent carbolic 

 acid was then added in sufficient quantity to form a 0.5 per cent solution. The 

 suspension was then centrifuged for five hours at a velocity of 4,000 revolutions 

 per minute and the clear fluid above, pipetted from the bacterial sediment. 

 Cultures from this fluid remained sterile. The animals were inoculated as below. 

 On June 11, one month after the first injection, the immunity of the animals 

 was tested in the following manner : One 48-hour agar slant culture of "Pest 

 Virulent" (from guinea pig number 2067, second transplant) was suspended in 

 5 cubic centimeters of bouillon, and 5 oesen of this suspension then rubbed over 



* The culture tubes designated in these experiments as "large" contain a 

 surface of agar of more than twice the area of that in the tubes ordinarily 

 employed in bacteriological work. 



