138 R. W. GLASER. 



best to sacrifice one or two animals by exploration dissections, 

 and by staining the excised tissue, in order to obtain an idea of 

 the exact position of the desired cells and their microorganisms. 

 When the region of the bacteriocytes has been discovered a fresh 

 animal can be taken, etherized, pinned to a paraffin tray ventral 

 side up, washed off with some sterilizing agent such as alcohol 

 or a mixture of alcohol and corrosive sublimate and dissected 

 with sterile instruments. The excised bacteriocytes with their 

 contents can then be directly placed in the different sterile media 

 and incubated. 



The following are descriptions of the morphological, cultural 

 and biochemical characters of the two species of organisms ; one 

 from Parcoblatta virginica and the other from Periplaneta amer- 

 icana. I consider it rather useless to give these bacteria specific 

 names. To begin giving names to all of the thousands of sym- 

 bionts, I think, would confuse rather than assist matters. It 

 would be far better accurately to designate the host and then 

 simply to refer to the genus of microorganism. In the case of 

 disymbiotic and trisymbiotic insects one can refer to the two or 

 three genera of symbionts associated with the host. If the two 

 or three symbionts all belong to the same genus, the latter can be 

 designated and the organisms labelled a, b, c, or i, 2, 3. 



The two species of organisms investigated by me are rather 

 pleomorphic in cultures. Some individuals are straight like a 

 bacillus ; others are comma- or crescent-shaped like a spirillum. 

 In the host cells the individuals are nearly all of the spirillum 

 form. For this reason and owing to the fact that the organisms 

 have one polar flagellum and do not form endospores, I am plac- 

 ing them in the genus Spirillum. 



The organisms found by me in Parcoblatta and Periplaneta 

 seem to differ from the morphological description of Bacillus 

 cuenoti of Mercier. Since the cultural and biochemical charac- 

 ters of B. cuenoti were not described it has been rather difficult 

 to make a comparison, however. The organism of Mercier seems 

 to be a true bacillus, forming endospores of oval shape. The 

 two organisms which I cultivated form no endospores. 



