VIBRIO BEROLINENSIS. 369 



Vibrio danubicus. Heider. (C. B. xi v, 341.) 



(Plate 53, I, in, iv.) 



Nothing peculiar microscopically (53, iv). Gelatin is powerfully 

 liquefied. Stab cultures remind one of very actively liquefying 

 cholera cultures. In our cultures the form of liquefaction was always 

 more like a saucer than a flattened funnel. Upon very thick plates it 

 is very similar to the cholera vibrio; upon thinner plates, after twenty- 

 two hours at 22, the surface colonies spread out exceedingly thin, are 

 irregular, and have a border which is wavy or provided with coarse 

 outgrowths. They are almost colorless and very delicately and uni- 

 formly marked with fine striations. Our illustration corresponds 

 with this in general (53, in). Milk is coagulated; upon potato there 

 occurs in the incubator a brownish, miserable growth. It gives the 

 indol reaction well. Pathogenic for guinea-pigs, less for pigeons. Cul- 

 tivated by Heider from the water of the Vienna canal of the Danube 

 at a time when no cholera was known to exist in Vienna; later 

 detached cases of cholera occurred. 



Vibrio aquatilis. Giinther. (Deut. tned. Woch., 

 1892, 1124.) 



(Plate 53, n, vn, vm, ix.) 



Microscopically not specially different from the cholera vibrio (53, 

 Vin). The colonies in gelatin plates, however, are easily distin- 

 guished from those of the cholera vibrio by the smooth or slightly 

 wavy border (never with granular irregularities) and very fine granules 

 (53, ix ). In Plate 53, vn, we have reproduced a quarter of a very 

 remarkable deep picture in a thinly sown gelatin plate. The sur- 

 rounding, numerous, secondary colonies are to be explained by soften- 

 ing of the gelatin (too high temperature). Older gelatin plate cul- 

 tures are similar to the cholera vibrio; the liquefaction is slow. There 

 is no nitroso-indol reaction, but a strong odor of sulphuretted hydro- 

 gen. It is not pathogenic. Weibel found a similar vibrio in a well 

 which had been infected with cholera vibrios a long time before (C. B. 

 xm, 117). 



Vibrio berolinensis. Rubner. (Neisser, A. H. xix, 194.) 



(Plate 53, V, VI.) 



Microscopically like the Vibrio cholerae (53, vi). We also found 

 the gelatin plate cultures very similar to those of cholera. There is 

 a tendency to the formation of coarser lobulations, and a finer granula- 

 tion of the colony is striking. Liquefaction of gelatin is minimal. 

 Strong nitroso-indol reaction. Considerably pathogenic for guinea- 

 pigs. 



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