io4 



SOLID CULTIVATION MEDIA. 



do not flourish so well in peptonised jelly as in this medium, and 

 notably for the culture of the tubercle bacillus. 



Fig- 55 

 cultivated 



test-tube, 



Koch). 



— Tubercle bacillus 

 upon solid serum in 

 glass capsule (after 





Fig. 56. — Tubercle bacillus upon solid 

 serum. 



At an even summer temperature the 

 tubercle bacillus flourishes admirably in 

 this soil, and presents a quite character- 

 istic appearance. It grows in the form 

 of a delicate white pellicle (see Fig. 55), 

 which has a flaky, almost fluffy, appear- 

 ance, and a dull granular surface, which 

 forms a marked contrast to that of the 

 solid serum, which is smooth and shin- 

 ing. This pellicle covers the whole of the 

 surface of the serum in course of time, 

 and forms a thin membrane over the 

 few drops of moisture which occupy 



