iv.] ARTIFICIAL COMMA-BACILLI. Si 



comma-bacilli, as many observers state, but is dependent on 

 the strength of the gelatine, and particularly on the method 

 of inoculation; no doubt in 10 per cent, nutritive gelatine, 

 and under the same conditions of inoculation, e.g. by using 

 a trace for inoculation and by the platinum wire, a con- 

 spicuous funnel-shaped depression of the surface and 

 occlusion of it by an air-bubble will be noticed in most 

 instances, but this is absent if the gelatine is weaker than 

 10 per cent., and if the inoculation is carried out in a 

 different manner. Furthermore, I have seen very conspicu- 

 ous funnel-shaped depressions and occluding air-bubbles in 

 10 percent, nutritive gelatine tubes containing other than 

 choleraic comma-bacilli ; certain micrococci and several 

 species of bacilli that possess the power of liquefying 

 gelatine, when inoculated by means of a platinum wire, have 

 in many instances shown the same funnel-shaped depression 

 and the occluding air-bubble. 



(//) On potato. On boiled potato kept under a moist bell- 

 glass the choleraic comma-bacilli grow readily when kept at 

 temperatures varying between 32 and 37 C. From the 

 place of inoculation the growth extends in the shape of a thin 

 light-brown translucent film, in which, as time goes on, say 

 after one to two weeks, thicker brownish spots and patches, 

 due to local increase of the growth, appear. At tempera- 

 tures varying between 18 and 22 C., even after several 

 days, only a trace of growth can be made out with a 

 lens. 



