428 



CHOLERA. 



This organism can, however, be readily distinguished from the cholera, 

 organism by the effects of inoculation on animals, especially on pigeons and 



guinea-pigs. Subcutaneous inoculation of small 

 quantities of pure culture in pigeons is followed 

 by septicaemia which produces a fatal result 

 usually within twenty-four hours. Inoculation 

 with the same quantity of cholera organism pro- 

 duces practically no result ; even with large 

 quantities death is rarely produced. The vibrio 

 Metchnikovi produces somewhat similar effects 

 in the guinea-pig to those in the pigeon, sub- 

 cutaneous inoculation being followed by exten- 

 sive haemorrhagic oedema, and a rapidly fatal 

 septicaemia. Young fowls can be infected by 

 feeding with virulent cultures. We have evi- 

 dence from the work of Gamaleia that the toxins 

 of this organism have somewhat the same action 

 as those of the cholera organism. 



The organism is therefore one which very 

 closely resembles the cholera organism, the 

 results on inoculating the pigeon offering the 

 most ready means of distinction. It gives a 

 negative reaction to Pfeiffer's test ; that is, the 

 properties of an anti-cholera serum are not 

 exerted against it. It may also be mentioned 

 that an organism which is apparently the same 

 as the vibrio Metchnikovi was cultivated by 

 Pfuhl from water, and named V. Nordhafen. 



Spirillum Schuylkiliensis. A spirillum 

 similar in its cultural characters and pathogenic 

 properties to Sp. Metchnikovi has been isolated 

 from the waters of the Schuylkill river at Philadelphia, by Abbott, and termed 

 by him spirillum Schuylkiliensis. 



Finkler and Prior's Spirillum. These observers, shortly after Koch's 

 discovery of the cholera organism, separated a spirillum, in a case of cholera 

 nostras, from the stools after they had been allowed to decompose for several 

 days. There is, however, no evidence that the spirillum has any causal 

 relationship to this or any other disease in the human subject. Morphologi- 

 cally it closely resembles Koch's spirillum, and cannot be distinguished from 

 it by its microscopical characters, although, on the whole, it tends to be rather 

 thicker in the centre and more pointed at the ends (Fig. 145). In cultures, 

 however, it presents marked differences. In puncture cultures on gelatin it 

 grows much more quickly, and liquefaction is generally visible within twenty- 

 four hours. The liquefaction spreads rapidly, and usually in forty-eight hours 

 it has produced a funnel-shaped tube with turbid contents, denser below 

 (Fig. 144, B). In plate-cultures the growth of the colonies is proportionately 

 rapid. Before they have produced liquefaction around them, they appear, un- 

 like those of the cholera organism, as minute spheres with smooth margins.. 



A B 



FIG. 144. Puncture cultures 

 in peptone gelatin. 



A. Metchnikoff 's spirillum. Five 

 days' growth. 



B. Finkler and Prior's spirillum. 

 Four days' growth. Natural size. 



