GENUS BACILLUS 343 



blood agar serum colonies appear which resemble somewhat 

 those of B. subtilis. A halo-like zone appears about the peri- 

 pheral part of the colony. Jordan and Harris found certain 

 agglutination reactions. 



Potato. No growth was observed by Jordan and Harris 

 on this medium. Luckhardt 2 obtained a luxuriant growth on 

 potato. 



Blood serum. At the end of 48 hours there occurs along 

 the needle track and confined to it an elevated, fairly vigorous, 

 smooth, moist, yellowish, glossy growth, which later tends to 

 spread but little. There is no discoloration of the medium, 

 liquefaction, nor odor. 



Bouillon. At the end of 24 hours there may not be any 

 growth noticeable except sometimes a slight clouding of the 

 broth at the surface. At the end of 48 hours there is seen on 

 the surface a well-formed pellicle, which will sink if the tube 

 is agitated ; the rest of the medium is feebly clouded and there 

 may be a fine semiflocculent sedimented growth at the bottom 

 of the tube or along the dependent side, if the tube has been 

 inclined. 



Litmus milk. If not heavily seeded there may be no vis- 

 ible signs of growth. As a rule there is no change at the end 

 of 48 hours; by 72 hours the cream ring will show a delicate 

 green-blue color in the drier parts, and even in some instances 

 the upper portion of the milk will show a slight alkaline reac- 

 tion ; this reaction daily increases until at the end of ten days 

 the whole tube takes on an alkaline reaction which becomes 

 more and more marked until as in cultures of B. suipestifer 

 the medium may lose a part of its color, turning a dirty white, 

 or even begin to turn opalescent. Coagulation has not been 

 observed. 



Life conditions and properties. The temperature best 

 suited for the growth of this organism seems to be from 30 

 to 37 C. It is an aerobe, as it does not grow in the closed 

 branch of the fermentation tube. Indol is not produced. 



2 Luckhardt, Jour, of Inf. Diseases, Vol. VI (1909) p. 492. 



