624 



The Spirillum of Denecke 



Like the related species, this micro-organism is actively motile and possesses a 

 terminal flagellum. 



Cultivation. — It grows at the room temperature, as well as at 37°C., in this 

 respect, as in its reaction to stains, much resembling the other two. 



Colonies. — Upon gelatin plates the growth of the colonies is much more rapid 

 than that of the cholera spirillum, though slower than that of the Finkler and 

 Prior spirillum. The colonies appear as small whitish, round points, which soon 

 reach the surface of the gelatin and commence liquefaction. By the second day 

 each is about the size of a pin's head, has a yellow color, and occupies the bottom 

 of a conical depression. The appearance is much like that of colonies of the 

 cholera spirillum. 



The microscope shows the colonies to be of irregular shape and coarsely granu- 

 lar, pale yellow at the edges, gradually becoming intense toward the center, and 

 at first circumscribed, but later surrounded by clear zones, resulting from the 

 liquefaction of the gelatin. These, according to the illumination, appear pale or 

 dark. The colonies differ from those of cholera in the prompt liquefaction of the 

 gelatin, the rapid growth, yellow color, irregular form, and distinct line of 

 circumscription. 



Fig. 251. — Spirillum oi Denecke; gelatin puncture cultures aged forty-eight and 

 sixty hours (Shakespeare). 



Gelatin Punctures. — In gelatin punctures the growth takes place all along the 

 track of the wire, and forms a cloudy liquid which precipitates at the apex in the 

 form of a coiled mass. Upon the surface a delicate, imperfect, yellowish scum 

 forms. Liquefaction of the entire gelatin generally requires about two weela. 



Agar-agar.^ — Upon agar-agar this spirillum forms a thin yellowish layer which 

 spreads quickly over most of the surface. 



Bouillon. — In bouillon the growth of the organism is characterized by a diffuse 

 turbidity. No gas-formation occurs in sugar-containing ihedia. 



Potatoes. — The culture upon potato is luxuriant if grown in" the incubating 

 oven. It appears as a distinct yellowish, moist film, and when examined micro- 

 scopically is seen to contain beautiful long spirals. 



Metabolic Products. — The organism produces no indol. 



Pathogenesis. — The spirillum of Denecke is mentioned only because of its 

 morphologic resemblance to the cholera spirillum. It is not associated with any 

 human disease. Experiments, however, have shown that when the spirilla are 

 introduced into guinea-pigs whose gastric contents are alkalinized and whose 

 peristalsis is paralyzed with opium, about 20 per cent, of the animals die. 



