476 CHOLERA 



sediment, leaving the fluid clear. All such methods, however, 

 require considerable experience on the part of the observer. 



A number of other spirilla have been cultivated, which are of 

 interest on account of their points of resemblance to .the cholera 

 organism, though probably they produce no pathological con- 

 ditions in the human subject. 



Metchnikoff's Spirillum (vibrio metchnikovi). — This organism was 



obtained by Gamaleia from an epidemic disease of fowls in Odessa, and is 



of special interest on account of its close resemblance to the cholera 



organism. 



Morphologically the organism is practically identical with Koch's 



spirillum (fig. 140). It is 

 ^a \fc actively motile, and has the 



•n <W^ ' 4 same staining reactions. Its 



r — ji 'A ''•"* » growth in peptone-gelatin 



^Af-a >-^ ' t-f\ ^ . a l s0 closely resembles that 



* ' s "• ' ' ' ' of the cholera organism, 



though it produces lique- 

 faction more rapidly (Fig. 

 141, A). After liquefaction 

 occurs, some of the colonies 

 are almost identical in ap- 

 pearance with those of the 

 cholera vibrio, whilst others 

 show more uniformly turbid 

 contents. In puncture cul- 

 -7 tures the growth takes place 



"*£*— I J '-*•« ».!'.>* more rapidly, but in appear- 



ance closely resembles that 

 d^t ' of the cholera organism a 



few days older. Its growth 

 Fig. 140. — Metchnikoff's spirillum, both in in peptone solution, too, 

 curved and straight forms ; from an agar j s closely similar, and it 

 culture of twenty-four hours' growth. als0 „ ives tne cholera-red 



Stained with weak carbol-fuchsin. x 1000. reaction 



This organism, can, how- 

 ever, 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 culture produces 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, subcutaneous 

 inoculation being followed by extensive hemorrhagic oedema and a rapidly 

 fatal septicaemia. Young fowls can be infected by feeding with virulent 

 cultures. We have evidence 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 » negative reaction to Pfeiffer's test — that 





