QUALITATIVE BACTERIOLOGICAL ANALYSIS. 87 



Bacillus Denitrificans (Jensen). 



A culture of this organism obtained from Krai's laboratory 

 gave the following cultural characteristics : The surface colonies 

 in gelatine plates were very thin and translucent, with a foliated 

 margin and a dark granular centre. In broth there was a 

 diffused growth and a slight film on the surface. On potato a 

 yellowish-brown rather slimy looking growth appeared. In 

 glucose and lactose media there was no gas formation. Milk 

 remained unchanged in appearance. On an agar-slope there 

 was a thick growth along the line of inoculation surrounded by 

 a thin transparent film with a crenated margin. In stab-gelatine 

 there was a thick white growth on the surface and along the 

 stab. In peptone solution no indol reaction was obtained on 

 adding a nitrite and a little pure sulphuric acid. In nitrate- 

 broth there was a good growth and the nitrates were found to 

 be reduced ; the reduction process was found to be very marked 

 when the bacillus was grown in conjunction with B. coli. 

 Microscopically the bacillus resembled B. subtilis in its move- 

 ment, but was smaller in size. It did not stain Gram; no growth 

 was obtained under anaerobic conditions. 



