1 84 MARSHALL HERTIG. 



individual bacteroids which had been isolated by the pipette 

 method of Barber ('14). Individual bacteroids obtained from 

 Blatta orientalis were placed in hanging drops of peptone or 

 ascitic fluid-bouillon. These bacteroids were charted and 

 observed at frequent intervals. Ten hanging drops were made, 

 the total number of bacteroids in these drops being about 100. 

 No growth whatsoever of the bacteroids or of any other organism 

 took place in these hanging drops. Single bacteria from a 

 laboratory culture placed in control hanging drops multiplied 

 readily. The results of the entire seiies of culture experiments 

 on the three species of Blattidse indicate that the bacteroids do 

 not grow readily, if at all, on routine culture media. 



It is thus seen that the culture studies of the various investi- 

 gators have yielded conflicting results. The three earlier 

 investigators, Blochmann, Krassilschtschik and Forbes, did not 

 succeed in growing the bacteroids. Mercier obtained from 

 Blatta orientalis an organism closely resembling a number of 

 common contaminators. If the bacteroids could be grown on 

 routine media as readily as Bacillus cuenoti, it should be possible 

 to obtain this organism in all cultures inoculated with bacteroids 

 from any stage in the life history of the roach, i.e., from the fat- 

 body, egg or embryo. The work of Javelly and the writer, in 

 which many sterile cultures were obtained, and in which Bacillus 

 cuenoti was not found, would seem to indicate that Mercier's 

 organism was itself a contaminator. The results of Javelly and 

 the writer further agree in indicating that the bacteroids of 

 Blatella getmanica as well as those of Blatta orientalis do not 

 grow readily, if at all, in routine culture media. 



In Glaser's work with Periplaneta americana and Parcoblatta 

 virginica, he obtained from each species a spirillum, these two 

 spirilla differing from each other only in minor cultural charac- 

 teristics. They differ markedly, however, in both morphology 

 and cultural characteristics from Mercier's Bacillus cuenoti. 

 Glaser inoculated his cultures with bacteroids obtained from the 

 fat-body of adults. The abdomen was washed with alcohol or 

 a mixture of alcohol and corrosive sublimate, and dissected with 

 sterile instruments. The portions of fat-body containing 



