220 BACTERIOLOGY. 



seen to be lozenge or whetstone in shape, while often 

 they appear as irregular stars with blunt points, and 

 again as irregularly lobulated dense masses. In struc- 

 ture they are conspicuous for their density. Under the 

 low objective they appear, when on the surface, as 

 coarsely granular, irregularly round patches, with more 

 or less ragged borders and a dark irregular central 

 mass, which has somewhat the appearance of masses of 

 coarser clumps of the same material as that composing 

 the rest of the colony. Microscopically, these colonies 

 are composed of small round cells, irregularly grouped 

 together. They are in every way of the same appear- 

 ance as those seen upon the original cover-slip prepa- 

 rations. 



Prepare from one of these colonies a pure stab culture 

 in gelatin. After thirty-six to forty-eight hours lique- 

 faction of the gelatin along the track of the needle, and 

 most conspicuous at its upper end, will be observed. 

 As growth continues the liquefaction becomes more or 

 less of a stocking-shape, and gradually widens out at its 

 upper end into an irregular funnel. This will continue 

 until the whole of the gelatin in the tube eventually 

 becomes fluid. There can always be noticed at the 

 bottom of the liquefying portion an orange-colored or 

 yellow mass composed of a number of the organisms 

 which have sunk to the bottom of the fluid. 



On potato the growth is quite luxuriant, appearing 

 as a brilliant orange-colored layer, somewhat lobulated 

 and a little less moist than when growing upon agar. 

 It does not produce fermentation with gas-production. 

 It belongs to the group of facultative aerobes. 



In milk it rapidly brings about coagulation with 

 acid reaction. 



