138 BACTERIOLOGY. 



about liquefaction, it will soon be discovered that this 

 result is by no means of the same appearance for all 

 organisms. Some organisms cause a liquefaction which 

 spreads across the whole upper surface of the gelatin 

 and continues gradually downward; again, it occurs in 

 a funnel-shape, the broad end of the funnel being upper- 

 most and the point downward, corresponding to the 

 track of the needle. At times a stocking- or sac-like 

 liquefaction may be noticed. (See Fig. 34.) 



Note. — Obtain a number of organisms from differ- 

 ent sources in pure cultures by the method given. Plant 

 them as pure cultures, all at the same time, in gelatin — 

 preferably gelatin of the same making — retain them 

 under the same conditions of temperature, and sketch 

 the finer differences in the way in which liquefaction 

 occurs. 



