176 BACTERIOLOGY 



on the wall of the pharynx, shows on agar a yellowish-grey, 

 opaque, pap-like streak (Bacillus saprogenes I.). The second 

 kind, which he found in the foul- smelling perspiration on 

 the feet, exhibits numerous fine droplets upon agar, which 

 spread out and form a film as clear as water (Bacillus 

 saprogenes II.}. The third kind was found by him in 

 septic gangrenous pus. It develops a broad and nearly fluid 

 film on agar (Bacillus saprogenes III.). 



Spirillum concentricum was found by Kitasato in putrid 

 ox-blood, and shows elements twisted into a screw shape 

 and furnished with flagella, which impart to them a lively 

 motility. Eoundish, sharply-defined discs occur on the 

 gelatine plate, and display a concentric stratification con- 



Flagella 



Fio. 69. SPIRILLUM JMJBRUM WITH FLAGELLA. (After Loffler.) 



sisting of alternate transparent and opaque rings. The 

 gelatine is not liquefied. In thrust-cultures the microbe 

 grows mostly on the surface. The layer formed on agar is 

 firmly adherent ; on glycerine- agar the concentric arrange- 

 ment is distinctly apparent, while on potato no growth takes 

 place. 



Spirillum rubrum. This was discovered by Von Esmarch 

 in a mouse which had died of mouse septicaemia. The 

 spirilla possess an active motility, and are provided with 

 flagella, according to Loffler (fig. 69). Von Esmarch grew 

 them first in roll-cultures on gelatine. The colonies are 

 grey at the commencement, afterwards red ; they grow 

 with extraordinary slowness, and do not liquefy the gelatine. 

 A special point is that thrust-cultures show after some time 



