BACILLI : SPECIAL 



191 



days it commences to show some kind of concentric differen- 

 tiation. 



The colonies in the depth of the gelatine appear as 

 spherical small dots, white in reflected, brownish in trans- 

 mitted light. Fig. 72 is a good illustiation of a gelatine 

 plate culture of bacillus coli ; compare also Fig. 60. 





Fig. 62. 



-Film Specimen' of a Variety of Bacillis Coi.i, iriE individual 



B.\C1LLI CHIEFLY 0\'.\L RODS, SOME FEW C\"L1KDRICAL 



Equally characteristic is the streak culture on the slanting 

 surface of gelatine ; after twenty-four hours a greyish band, 

 thicker in the line of inoculation — grey, film}*, knobbed, or 

 crenated in the marginal part — after forty-eight hours it has 

 spread considerably in breadth, but has retained the above 

 aspect, except that the middle part is more thickened, and 



