60 



O. ISHII 



spontaneous agglutination according to age of cultures 



(table 10) 



WTien spontaneous agglutinating bacilli were grown in neu- 

 tral broth or pepton water, spontaneous agglutination was more 

 vigorous when cultures were but one day old, diminishing steadily 

 afterwards and almost disappearing on the fifth day. 



I concluded therefore that both spontaneous and specific agglu- 

 tinating power diminsh with the age of most strains of the colon- 

 typhoid group. 



TABLE 10 

 Spontaneous agglulinaiion according to age oj bacilli growing in plain broth at 



37° C. 



Key: 3, strong; 2, medium; 1, weak spontaneous agglutination. 



COMPARATIVE RESULTS OF MICROSCOPIC AND MACROSCOPIC AGGLU- 

 TINATION TESTS 



Chick, Dreyer, Garrow, Jordan, Panton, Walker, Wilson, 

 and several other investigators prefer the macroscopic method; 

 Delepine, Ritchie, and several other workers have used the 

 microscopic method. 



In using non-spontaneous agglutinating cultures, strong ag- 

 glutination could be seen equally well with either method, and 

 weak agglutination better by the microscopic method. For 

 instance, in some cases which appeared negative macroscopi- 

 cally, small clumps could be seen microscopically when examined 

 at the end of three hours. These small clumps are of great 

 value in certain cases of very weak reactions. This is especially 

 noticeable with the Bad. dysenteriae group, but less so for 



