The Cholera " Comma" Bacillus. By G. F. Dowdeswell. 955 



cell swells up, thickens, assumes a vacuolated form, remaining 

 active, which shows that the appearance is not due to degeneration ; 

 then the cor|iuscle thus formed divides into two new curved cells. 

 This occurs in cultivations of nutrient agar-agar at the tem- 

 perature of the laboratory (15°-20° C). The preparation under 

 the Microscope (one of Dr. Klein's) shows these phases very 

 beautifully. This observation is of the highest interest and quite 

 imparalleled in the biology of the lower fungi, justifying the state- 

 ment made, that this organism from a mycological point of view is 

 the most remarkable yet noticed. 



It does not form resting-spores, and thus its method of per- 

 petuation is quite obscure, as in the case of Bacterium termo, and 

 requires further careful investigation. There are appearances in 

 some of the cells at different stages of growth, which simulate 

 spores (or properly speaking conidia) very closely, and also in effete 

 cultivations, aggregations of minute spore-like or coccoid bodies, 

 which do not stain nearly as readily as the growing cells ; but 

 that they are not true spores or viable, is proved by the circum- 

 stance that the cultivations containing them, whether in gelatin 

 or liquid bouillon, are sterile when inoculated into fresh nutrient 

 media. 



Beyond the occurrence of longitudinal fission no form-variations 

 or involution phases have been established, the cells, however, 

 ultimately split up into short " primitive segments." This is the 

 origin of the beaded appearance sometimes observed in this and 

 other microbes. It has, however, been stated* that the large " worm- 

 like " bodies found in the intestines of guinea-pigs that have 

 been injected with cultivations of Koch's commas, are a morpho- 

 logical variety of the same species ; this appears clearly an error, 

 for as I have before stated,! in the large intestine of these animals 

 such organisms occur normally and commonly ; fungi they may be, 

 but they are very greatly larger than the cholera comma bacilli, 

 and no grounds have been adduced for supposing that there is any 

 genetic connection between them ; were there any, it would merely 

 further prove that the microbe is not pathogenic, as these forms 

 occur normally in healthy animals. 



As regards the habits of growth and behaviour of the organism 

 in different cultivating media, 1 may point out that in plain 

 bouillon it developes uniformly through the fluid, rendering it 

 turbid ; it forms no pellicle, but if pepton be added a slight scum 

 appears for a time, which may be mistaken for the occurrence of 

 contaminations. In nutrient gelatin, the macroscopical appearances 

 have been often described and are well known ; when inoculated 

 into the substance of the medium with a needle or a pipette, there 



* lirit. Med. Journ., 1885, p. 878. f Ibid., p. 588. 



