42 2 



jMICRO-ORGANISMS and disease [chap. 



soon a coalescence of the adjoining colonies, and then we 

 get a number of circular zones of clear, liquefied gelatine, 

 each with a ceirtral gray granular mass, the zones being 

 fused at the points of contact, ^^'hen during the further 

 growth the gelatine becomes liquefied over extensive areas, 



Fig. 17J. 



Pait of .1 test-tube contnining gelatine-peptone; in It pure cultivation of choleraic 

 comma-bacilli. The funnel-shaped opening of the ch.-umel in which the growth 

 of the comma-bacilli is going on contains a long air bubble. 



the outlines of the original colonies are lost, and on the 

 surface of the clear, liquefied gelatine are thin, filmy flakes, 

 and at the bottom are minute whitish granules. In all stages 

 before and after the liquefaction of the gelatine has become 

 well pronounced, there are found under the microscope 



