PATHOGENIC SPIRILLA. 



501 



ment is retarded by an unfavorable temperature, the presence of a 

 little alcohol, etc., the long, spiral filaments are quite numerous, and 

 bacteriologists generally agree that the so-called " comma bacillus " 

 is really only a fragment of a true spirillum. By Loffler's method 

 of staining the rods may be seen to have a single terminal flagel- 

 lum. In old cultures the bacilli frequently lose their characteristic 

 form and become variously swollen and distorted involution forms. 

 Hueppe has described the appearance of spherical bodies in the 

 course of the spiral filaments, which he believes to be reproductive 

 elements so-called arthrospores. 



Stains with the aniline colors usually employed, but not as quick- 

 ly as many other bacteria ; an aqueous solution of fuchsin is the 



FIG. 174. FIG. 175. 



FIG. 174. Spirillum cholerae Asiatic; colonies upon gelatin plate, end of thirty hours, x ICO. 

 Photograph by Frankel and Pfeiffer. 



FIG. 175. Spirillum cholerse Asiaticae, from a gelatin culture, x 1,000. From a photomicro- 

 graph. (Frankel and Pfeiffer.) 



most reliable staining agent; is decolorized by iodine solution 

 Gram's method. Sections may be stained with Loffler's solution. 



Biological Characters. An aerobic (facultative anaerobic), 

 liquefying, motile spirillum. Grows in the usual culture media at 

 the room temperature more rapidly in the incubating oven. Does 

 not grow at a temperature above 42 or below 14 C. Does not form 

 endogenous spores (forms arthrospores, according to Hueppe ?). 



In gelatin plate cultures, at 22 C. , at the end of twenty-four 



hours small, white colonies may be perceived in the depths of the 



gelatin ; these grow towards the surface and cause liquefaction of 



the gelatin in the form of a funnel which gradually increases in 



43 



