290 



PRACTICAL DAIRY BACTERIOLOGY 



and see if any large (usually about the size of a pinhead) colo- 

 nies appear on the surface, white in color and intensely acid 

 If so isolate one, preferably one that shows a gas bubble be- 



FIG. 82 MAKING GELATIN STABS 



neath or beside it. Inoculate upon an agar slant, labeling it 

 Bact. aerogenes(?}. Whether it is really that species will be 

 determined later. If no gas bubbles appear, isolate several of 



