422 APPLICATION OF METHODS OF BACTERIOLOGY 



When cultivated artificially it grows very slowly. 



Upon gelatin plates the colonies appear as round, sharply 

 circumscribed, punctiform masses which are slightly elevated 

 above the surface of the surrounding medium. Under a 

 low magnifying power they are seen to be slightly granular 

 and to present a more or less glassy lustre. 



The colonies increase but little in size after the third or 

 fourth day. If cultivated as stab-cultures in gelatin, there 

 appears upon the surface at the point of inoculation a cir- 

 cumscribed white point, slightly elevated above the surface 

 and limited to the immediate neighborhood of the point 

 of inoculation. Down the needle-track the growth is not 

 continuous, but appears in isolated, round, dense white 

 clumps or beads, which do not develop beyond very small 

 points. 



It does not liquefy gelatin. 



Upon plates of nutrient agar-agar the colonies appear as 

 small, almost transparent, round points, which have about 

 the same color and appearance as a drop of egg-albumen; 

 they are very slightly opaque. They are moist and glisten- 

 ing. They rarely develop to an extent exceeding 1 to 2 

 mm. in diameter. 



Upon agar-agar as stab- or slant-cultures the surface 

 growth has more or less of a mucoid appearance. It is 

 moist, glistening, and irregularly outlined. The outline of 

 the growth depends upon the moisture of the agar-agar. 

 It is slightly elevated above the surface of the medium. 



In contradistinction to the gelatin stab-cultures, the 

 growth in agar-agar is continuous along the track of the 

 needle. 



The growth on potato is a thick, irregular, slimy-looking 

 patch. 



