64 



SPIRILLUM RTJBRTJM. Von Esmarch. 



Origin. Isolated from the putrefied cadaver of a 

 mouse. 



Form. Clear, transparent, thick cells, which com- 

 monly are single, appearing as large bent rods or comma 

 bacilli (vibrio). May form spirals of 3 or 4 or even 40 

 windings. Involution forms are common in old cultures. 



Motility. Actively motile. Each end of a spiral 

 has one wavy flagellum. 



Sporulation. True spores not observed. 

 Anilin Dyes. Stain slowly but well. 

 Growth. Extremely s?o\v. 



Gelatin Plate 8 Owing to the very slow development of colonies ordinary 

 plates cannot be used. In roll tubes, colonies develop in from 7 to 10 days, and 

 at first are minute and grayish; later the center becomes tinged with pink 

 and eventually becomes red. The edge is smooth and contents finely 

 granular. 



Stick Cu//?nvx. Are the most characteristic. Growth takes place along 

 the entire line of inocukvtion, forming a row of colonies. The growth spreads 

 slightly on the surface and is colored a light pink. The pigment formation is 

 most marked along the stich where oxygen is absent. It passes through a 

 light pink to a beautiful dark wine-red color. Ordinary bacterial pigments 

 are formed only in the presence of air and are secondary products, whereas 

 this pigment is formed in the absence of air and is primary. 



Streak Cultures. On agar, forms moist, thick, non-spreading patches, 

 which, when old, possess a light pink or red color, especially near the center. 

 On potatoes, develops slowly, forming minute deep red colonies. On blood 

 serum, the growth is much the same as on agar. 



Milk. In fluid.media, milk, bouillon, etc., forms long spirals. 



Oxygen requirements. Is a facultative anaerobe. 



Temperature. Grows between 16 and 40. Opti- 

 mum about 370. 



Behavior to Gelatin. Not liquefied. 

 Pathogenesis. Has no effect. 



NOTE. Make Esmarch Roll-tubes of the Spirillum rubrum. 



