406 BACTERIA PATHOGENIC TO MAN 



Upon agar there is a somewhat more luxuriant growth than is seen with 

 the cholera vibrio. Upon potato this spirillum grows at room tempera- 

 ture and produces a slimy, grayish-yellow, glistening layer which soon 

 extends over the entire surface. The cholera spirillum does not grow 

 at room temperature, and in the incubator produces a thin, brownish 

 layer. The absence of agglutination with a suitable dilution of the 

 serum of an animal immunized to the cholera spirillum is a valuable 

 differential sign. 



In 1884 Miller observed a curved bacillus in a hollow tooth, which 

 from its behavior in microscopic preparations, in cultures, and animal 

 experiments, is probably identical with the Finkler and Prior spirillum. 

 Very similar spirilla have been found by others. 



Spirillum of Metchnikoff. 



Discovered in 1888, in Odessa, by Gamaleia in the intestinal con- 

 tents of fowls dying of an infectious disease, which prevails in certain 

 parts of Russia during the summer months, and which presents symp- 

 toms resembling fowl cholera. Gamaleia's experiments show that 

 this organism is the cause of the disease mentioned. It has since been 

 found by Pfuhl and Pfeiffer in the water of the Spree at Berlin, and 

 in the Lahn by Kutchler. 



Morphology. Morphologically this spirillum is almost identical 

 with the cholera spirillum. In the blood of inoculated pigeons the 

 diameter is sometimes twice as great as that of the cholera spirillum, 

 and almost coccus-like forms are often found. A single, long, undulat- 

 ing flagellum is attached to one end of the spiral filaments or curved 

 rods. 



Stains with the usual aniline colors, but not by Gram's method. 



Cultural Characters. Upon gelatin plates the vibrio Metchnikoff 

 grows considerably faster than the cholera vibrio; small, white, puncti- 

 form colonies are developed at the end of twelve hours; these rapidly 

 increase in size and cause liquefaction of the gelatin within twenty- 

 four to thirty hours. At the end of three days large, saucer-like areas 

 of liquefaction may be seen, the contents of which are turbid, as a 

 rule. In gelatin-stick cultures the growth is almost twice as rapid as 

 the cholera bacillus. In bouillon at 37 C. development is very rapid, 

 and the liquid becomes clouded and opaque, and a thin, wrinkled film 

 forms upon the surface. On the addition of pure sulphuric acid to 

 twenty-four-hour peptone cultures a distinct nitrosoindol reaction is 

 produced. Milk is coagulated and acquires a strongly acid reaction. 

 The spirillum is not agglutinated by the specific cholera agglutinin. 



Pathogenesis. The vibrio Metchnikoff is pathogenic for fowls, 

 pigeons, and guinea-pigs. A small quantity of a virulent culture fed 

 to chickens and pigeons causes their death with the local and general 

 symptoms of fowl cholera. At the autopsy the most constant appear- 

 ance is hypersemia of the entire alimentary canal. A grayish-yellow 

 liquid, more or less mixed with blood, is found in considerable quantity 



