﻿STUDIES IN PLAGUE IMMUNITY. 



199 



EXPERIMENTS IN THE IMMUNIZATION OF ANIMALS WITH LIVING, 

 ATTENUATED CULTURES (VACCINATION). 



Series 4. — Inoculation* with "Pest Avirulent" in monkeys. 



Six 24-lionr agar slant cultures of "Pest Avirulent" were suspended in 6 cubic 

 centimeters of bouillon (1 cubic centimeter to each culture), the whole mixed 

 and 1 cubic centimeter of the mixed suspension injected subcutaneously near the 

 root of the tail of each animal on October 10. Ten days later the immunity of 

 the animals was tested in the following manner: A 48-hour agar culture of 

 "Pest Virulent" (from guinea pig number 1221, second transplant) was sus- 

 pended in 5 cubic centimeters of bouillon and animals numbered 1228 to 1231 

 and controls numbered 1282 to 1285 were reinoculated by dipping a 10 cubic 

 centimeter syringe needle in this suspension and then thrusting the needle beneath 

 the shaven skin near the root of the tail, on the opposite side to that upon which 

 the vaccination had been made. Animals numbered 1232 and 1233 and controls 

 numbered 1286 and 1287 were reinoculated by dipping a scalpel several times in 

 this same suspension and rubbing it over the shaved abdomen and slightly 

 scarifying the skin with the knife. 



Animal 

 No. 



Vaccination 

 October 10. 



Reinoculated 

 October 20. 



Result. 



Autopsy and remarks. 



1228 



1229 

 1230 

 1231 

 1232 



1233 



1 agar cul- 

 ture. 



do 



do 



By sticking with 



infected needle. 



do 



_do 



Dead after 



8 days. 

 Alive 

 do 



Numerous pest bacilli from the spleen. 



do 



do 



do 



do 



By scarification 

 with infected 

 scalpel. 

 do ____ 



do 



do 



- d °- 



CONTROLS. 



1282 

 1283 



1284 



1285 

 1286 



1287 





By sticking with 

 infected needle, 

 do . 



Dead after 



6 days. 

 Dead after 



8 days. 

 Dead after 



10 days. 



Alive ... 

 do 



do _ 



Innumerable pest bacilli in smears from 



heart's blood and spleen. 

 Numbers of pest bacilli in smears from 



the spleen. 

 A few pest bacilli in smears from the 



spleen. Very numerous in smears 



from the swollen hajmorrhagic glands. 







.do 





do 





By scarification 

 with infected 

 scalpel. 



do___ 











