74 O. ISHII , 



Microscopic examination of the twenty-four-hour broth cul- 

 tures by the hanging drop method showed differences in morphol- 

 ogy and motility between those organisms which agglutinated 

 spontaneously and those which did not. In most cases the 

 bacilli which undergo spontaneous agglutination are longer, 

 sometimes having the appearance of being fungiform and show- 

 ing relatively greater motility. The bacilli which do not agglu- 

 tinate spontaneously are shorter and are less motile. 



COLONY CHANGES IN ARTinCIAL CULTURE MEDIA (TABLE 2) 



LoflHer (190G) found four types of colonies of Bad. coli: (1) 

 transparent, (2) flat, (3) thick, and (4) opaque. According to 

 his evidence, these types are constant and do not change. Baerth- 

 lein (1911) reported a cholera vibrio colony that did not change 

 after passage through animals, but in a stock culture twenty- 

 two days afterwards, in several subcultures, the yellow type 

 turned light and twenty-eight days later the light colony changed 

 to a yellow one. Steuihardt found spontaneous agglutination 

 in Bad. typhosum after the twentieth passage through bacteri- 

 cidal serum cultures. Teague and Mc Williams state that they 

 found some changeable bacilli, but they do not draw any 

 definite conclusions from their finding. 



According to our observation colonies of many strains of the 

 colon-typhoid group may lose the property of spontaneous 

 agglutination, while others that do not show this property at 

 first may show it after some time. 



From a stock culture we obtained colonies which were, and 

 others which were not, agglutinated spontaneously. These 

 were spread on plates of two per cent agar (using very high 

 dilution of the bacteria in broth or salt solution so that each 

 single colony should be separated from every other colony) and 

 incubated for 24 hours at 37°C. The colonies thus grown were 

 inoculated into broth tubes and placed in the incubator. Sub- 

 cultures were made every two days by inoculating one loopful 

 of the broth culture into a fresh tube of broth. The bacilli were 

 examined after each sub-culture by streaking a loopful of the 

 freshly inoculated broth on agar plates. The following results 

 on agar i)lates and in cultures were obtained: 



