﻿STUDIES IN PLAGUE IMMUNITY. 

 Table Number VIII. 



251 



Dilution. 



After 1 hour. 



After 2 hours. 



After 16 hours. 



Immune f 1:10 

 Serum. IControl. 



Normal j 1 : 10 

 Serum. < 



[Control . 



Positive 



Negative 



Positive .. „ 



Positive. 



Marked precipitate. 

 Do. 



Do. 





.... do 



Negative _ _ 



Marked flocculent precipitate. 







Agglutination tests were made of the same horse's serum, the animal having 

 received 10 agar cultures intravenously before this examination. The anti-infec- 

 tious power of the serum at this time was such that 1 cubic centimeter protected 

 60 per cent of the inoculated white rats against fatal pest infection. The results 

 are as follows: 



Table No. IX. — Immune serum Number III with strains " Maasscn Alt" and "Pest 



Avirulent." 



"MAASSEN ALT." 



Dilution. 



After 4 hours. 



After 20 hours. 



1:10 

 1:20 

 1:40 

 1:80 



fControl. 



IControl. 



Positive _ _ - . _ 



Positive. Fluid cleared. 



Moderate sediment. Fluid not clear. 



Do. 



Do. 



Do. 



Do. 



Negative _ _ 



do 



do. 



Very slight precipitate of bacteria ___ 

 Negative 



"PEST AVIRULENT." 



Dilution. 



After 2 hours. 



After 4 hours. 



1:10 



1:20 



1:100 



1:1,000 



1:2,000 



fControl. 



IControl. 



Positive . 



Positive. Fluid cleared. 



Do. 

 Negative. Slight sediment. 



Do. 



Do. 

 Sediment. Fluid not clear. 



Do. 





do_. 



do - 



do . 



do 



do 





The agglutination of Pest immune serum Numper IV, obtained from 

 a horse, was tested five months after its preparation. Its anti-infectious 

 value was such that 1 cubic centimeter protected 90 per cent of the 

 inoculated white rats against pest. The agglutination tests were made 

 with the strain "Pest Virulent" (second transplant) at this time in 

 dilutions of 1 : 10, 1 : 20, 1 : 100, 1 : 500, 1 : 1,000, with two controls. 

 All were negative after four hours except in the dilution of 1 : 10, where 

 a weak positive reaction occurred. 



55670 — —7 



