594 PATHOGENIC SPIRILLA. 
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 afragment of a true spirillum. By Léffler’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 
Fie. 174, Fie. 175. 
Fig. 174.—Spirillum choleree Asiatic; colonies upon gelatin plate, end of thirty hours. x 160. 
Photograph by Frankel and Pfeiffer. 
Fia. 175.—Spirillum cholerz Asiatic, from a gelatinculture. 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 Léffler’s solution. 
Biological Characters.—An aérobic (facultative anaérobic), 
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 
