334 A MANUAL OF BACTERIOLOGY 



sequently the struggle for existence was reduced to a 

 minimum. It is probable that this rare microbe is 

 an aerial form, but the author has not found it in the 

 atmosphere. 



E. pluviatilis grows well on gelatine plates, and in 

 four days forms a small yellow colony, with liquefac- 

 tion of the gelatine. The growth of this microbe in 

 gelatine-tubes is also characteristic, and in from thirty- 

 six to forty-eight hours after inoculation, it forms a 

 thin yellowish band with a number of small lateral 

 filaments. On the surface of the gelatine, there is 

 developed a brilliant yellow colony. In bouillon at 

 30 C. this microbe forms a yellowish pellicle on the 

 surface, and ultimately a flocculent deposit of the same 

 colour settles at the bottom of the tube. It grows 

 very rapidly on potatoes, giving rise to an orange 

 growth which extends over almost the whole surface 

 of the potato. 



B. pluviatilis occurs in pairs and threads; and 

 individual bacilli vary in length from 2 to 4 //,, and in 

 breadth from 0*6 to 0'8 yu,. This microbe, which 

 stains well with the aniline colours, does not produce 

 spores. It forms, in peptonise gelatine, a white 

 crystalline ptomaine having the formula C 9 H 21 N 2 5 . 



Neither the microbe nor ptomaine possesses any 

 pathogenic properties, 



V. THE CANCER BACILLUS. 



Scheuerlein has cultivated a special microbe from 

 cancerous tissues, which he considers as the veritable 

 agent in producing cancer. This microbe grows well 

 on solidified blood serum at 39 C. ; and after three 

 days' incubation, the whole surface of the medium is 

 covered with a colourless pellicle. After many days 



