8o THE BACTERIA IN ASIATIC CHOLERA. [CH. 



Those containing 10 per cent, gelatine show the characters 

 above described, the channel cf inoculation is a thin greyish 

 line of liquefied gelatine, funnel-shaped at the top, and with 

 an occluding air-bubble, and at the bottom a small amount 

 of precipitate; the other containing 5 per cent, nutritive 

 gelatine, contains the growth in the shape of a broad cone 

 of liquefied gelatine, broadest at the top, but with no 

 funnel-shaped depression. The air-bubble is present in 

 10 per cent, nutritive gelatine, if during inoculation the 

 comma-bacilli are well pushed down into the channel, as is 

 sometimes the case when the inoculation is performed with 

 a trace only, and by the platinum wire. With such a method 

 of inoculation, most of the comma-bacilli are deposited at 

 the bottom, few or none remain in the superficial parts, 

 hence when active multiplication sets in, most of the growth 

 takes place in the depth and away from the surface. By 

 using a capillary glass pipette containing the comma-bacilli 

 for inoculation, it can easily be arranged that the channel of 

 inoculation receives comma-bacilli in its whole length. This 

 can be achieved by holding the bulb of the pipette with the 

 fingers, and thereby warming it, before withdrawing the pipette 

 from the gelatine; not only is hereby a deposit of comma- 

 bacilli ensured in the superficial layer also, but as a rule more 

 comma-bacilli are deposited here than in the depth, because 

 owing to the shape of the capillary pipette the channel of 

 inoculation is at the outset broader on the surface than in 

 the depth. When all these conditions are successfully 

 fulfilled, it will be found that only a slight funnel-shaped 

 depression will be noticeable after a few days, and con- 

 sequently no air-bubble ever marks the mouth of the 

 channel. The air-jbubfele, then, occluding the mouth of the 

 funnel cannot be ^regarded as something quite typical and 

 characteristic o? a gelatine tube-cultivation of choleraic 



