VARIOUS SPIRILLA 543 



curved or straight rods, and sometimes as spiral filaments. It is 

 aerobic and facultatively anaerobic, does not form spores, and does 

 not stain by Gram's method. In a gelatin stab -culture a yellowish 

 growth forms with rapid liquefaction (Plate XX., d). On agar 

 a thick, slightly brownish, moist layer develops. Serum is rapidly 

 liquefied. On potato a slimy brownish growth occurs even at 

 room temperature. It grows in broth and peptone- water, pro- 

 ducing a general turbidity. It does not as a rule give the indole 

 reaction with sulphuric acid alone, but the ordinary laboratory 

 cultures after three to four days' growth occasionally give a slight 

 reaction. It is stated to be pathogenic to guinea-pigs by intra- 

 peritoneal inoculation. 



Spirillum tyrogenum 



Obtained by Deneke from old cheese, and frequently termed 

 Deneke's spirillum. It forms curved rods and spiral filaments 

 somewhat closely resembling the Koch vibrio. It grows well on 

 the ordinary culture media at room temperature, but development 

 is usually slight or absent at 37 C. In a gelatin stab-culture a 

 yellowish growth occurs with liquefaction, which is much more 

 rapid than that of the Koch vibrio, but less so than that of the 

 Finkler-Prior spirillum. On agar a thinnish, brownish, somewhat 

 membranous and coherent layer slowly develops at room tempera- 

 ture. On potato a yellowish growth occurs. It is stated to be 

 slightly pathogenic to guinea-pigs by intra-peritoneal inoculation. 



Spirillum rubrum 



A chromogenic spirillum obtained by Koch from the putrefying 

 tissues of a mouse. In a gelatin stab-culture a dark red growth 

 slowly develops along the line of puncture without liquefaction ; 

 at the surface, however, the growth is colourless. In broth at 

 37 C. it grows freely, producing a general turbidity with a red 

 deposit at the bottom of the tube ; there is no film formation. 

 In such a broth culture large numbers of typical spirillar filaments 

 can be seen, which are thin and delicate, of varying length, and 

 actively motile. It is non-pathogenic. 



Vibrios are common in the mouth, and may be met with in the 

 discharge of septic ulcers. 



