﻿STUDIES IN PLAGUE IMMUNITY. 



217 



Series 52. — Inoculations with the strain "Maassen Alt" in monkeys. 



Twenty-two 48-hour agar slant cultures of the strain "Maassen Alt" were 

 suspended in 22 cubic centimeters saline solution ( 1 cubic centimeter to each 

 culture). Monkeys numbered 2721 to 2728 received subcutaneously each 2 cubic 

 centimeters, equal to 2 agar slant cultures. Monkeys numbered 2729 to 2735 

 each received 1 cubic centimeter, equal to 1 agar slant culture. On November 28, 

 one month after the vaccination, the immunity of the animals was tested by 

 the subcutaneous injection of the strain "Pest Virulent" in exactly the same 

 manner as was the immunity of the animals in Series 48 and 51. (See pp. 195 

 and 203.) Twenty- five control animals, numbered 2896 to 2020, were also inocu- 

 lated in the same manner with the same suspension and succumbed to acute 

 infection. For the details of the protocols see Series 48. 



Animal 

 No. 



Vaccinated 

 October 26 sub- 

 cutaneously 

 with— 



Infected 



November 28 



with— 



Result. 



Autopsy and remarks. 



2721 



2 agar cul- 

 tures strain 

 "Maassen 

 Alt." 



| oese strain 

 "Pest Viru- 

 lent." 



Alive and well _ 



. 



2722 



.do 





Dead Nov. 8, af- 

 ter vaccina- 



No evidence of bubo or inflammation 

 at point of inoculation. Cover slips 













tion. 



no excess of leucocytes, no bacteria. 

 ■ Cultures from spleen and point of 

 inoculation negative. Three cul- 

 tures. Large amounts material in- 

 oculated. 



2723 



do 



| oese strain 

 "Pest Viru- 

 lent." 



Alive and well _ 





2724 



do 



do 



Dead Dec. 4, 



Numerous pest bacilli in smears from 









after 6 days. 



spleen. 



2725 



__ do 



-do . . 



-do 



Bubo with numerous pest bacilli. 



2726 



do_ 



do 



Alive and well _ 



2727 

 2728 



do 



____ do 



do 



Numerous pest bacilli in smears from 



do 



do 



Dead Dec. 1, 





- 





after 3 days. 



spleen. 



2729 



1 agar cul- 

 ture strain 

 "Maassen 

 Alt." 



do 



Alive and well . 





2730 



___.do 



do 



Dead Dec. 3, 



Bubo. Numerous pest bacilli in 









after 5 days. 



smears from spleen. 



2731 

 2732 

 2733 



do - - _ 



_.__do_ 



Alive and well . 

 .do 



Bubo. Few pest bacilli. 



__ do 



do 



do 



do 



Dead Dec. 3, 









after 5 days. 





2734 



do 



do 



Dead Dec. 1, 

 after 3 days. 



Innumerable pest bacilli in smears 

 from spleen. 







2735 



do 



___do 



Dead Dec. 2, 

 after 2 days. 



Bubo. Fair numbers of pest bacilli 

 in smears from spleen. 







