﻿STUDIES IN PLAGUE IMMUNITY. 



191 



Series 23. — Killed and living agar cultures of "Pest Virulent" with monkeys. 



Twenty-five 48-hour agar slant cultures of "Pest Virulent" (from guinea pig 

 number 1496, second transplant) were suspended in 25 cubic centimeters of 

 bouillon. The suspension was placed in an incubator registering 60° C. for one 

 and one-half hours. After its removal, cultures were taken, which, two days later, 

 developed colonies of pest bacilli (three colonies to two large loops of the suspen- 

 sion.) Evidently, the temperature of the very concentrated suspension of bacilli 

 had not reached 60° C, although a thermometer placed in a test tube containing 

 bouillon in the incubator registered this temperature during the heating. With 

 this suspension containing killed and also a moderate number of living pest bacilli 

 this series of animals was inoculated as below on December 4, 1900. On December 

 IS, two weeks after the first inoculation, the animals which remained alive 

 were reinoculated in the following manner. Nine 48-hour agar slant cultures of 

 '"Pest Virulent" (from guinea pig number 1510, second transplant) were suspended 

 in 45 cubic centimeters of bouillon, and each animal was reinoculated subeutane- 

 ously on the opposite side of the body to that on which the first inoculation was 

 made with 0.2 cubic centimeter of this suspension, that is with a little less than \ 

 oese of "Pest Virulent." 



Animal 

 No. 



Inoculated De- 

 cember 4 subeu- 

 taneously with — 



Infected 



December 18 



with — 



Result. 



Autopsy and remarks. 



151S 



1 killed agar 





Dead from first 



A few pest bacilli in smears from 





slant "Pest Vir- 





inoculation 



the spleen. 





ulent." 





Dec. 6, after 2 

 days. 





1519 



do 





do 



Very numerous pest bacilli in 

 smears from spleen. 









1520 



_ ..do 



Nearly J oese 



Dead Dec. 20 



Culture from the spleen negative. 







"Pest Viru- 





Numerous pest bacilli in smears 







lent." 





from the bubo.* 



1521 

 1522 

 1523 

 1524 

 1525 

 1526 

 1527 



do 



do 



Alive 



Smears from point of inoculation 

 show no bacilli. Cultures from 



.. do 



do 



do 



... do 



__ do 



do — - 



do 



do 



____ do. - ... 



do 



... do 



__. do . 



do 



do 



... do . . 



do 





Dead from first 

 inoculation 













Dec. 6, after 2 



spleen show numerous pest 









days. 



bacilli. 



1528 



2 killed agar 



Nearly J oese 



Dead Jan. 4, after 



Numerous pest bacilli in smears 





slants "Pest 



"Pest Viru- 



17 days. 



from spleen. Large suppurat- 





Virulent." 



lent." 





ing bubo. 



1529 



do 



do 







1530 

 1531 

 1532 

 1533 



do 



...do 



do 



Abscess at point of inoculation 

 containing pest bacilli. 



do 



do_. .. 



do - . 



do 



do 



do 



do . 



do 



Dead Dec. 24, 

 after 6 days. 







1534 



do 



do 



Alive . . 





1535 



% killed agar 



do. 



Dead Dec. 20, 



Very numerous pest bacilli in 





slant "Pest Vir- 





after 2 days. 



smears from spleen.* 





ulent." 









* It is possible that these animals were suffering with a latent or chronic form of pest at the time 

 of the second reinoculation, although they were apparently healthy. 



