XVI] VIBRIO AND SPIRILLUM 417 



England in 1893) the commas derived from different 

 undoubted cases of cholera represent different varieties, that 

 is to say they are in their general characters and reactions 

 cholera vibrios, but in the details of the appearances of 

 their growth in the different media they differ in a definite 

 manner, which are not merely of an accidental or transitory 

 character but are differences maintained by them in sub- 

 culture through a number of successive transferences. 

 These facts fully confirm the statements first made 

 by D. D. Cunningham (Scientific Memoirs) derived from 

 observation of cholera in Calcutta, and although at first 

 doubted (as for instance by Hueppe and Gruber at the 

 International Congress of Hygiene held in London in i8gi) 

 they are now admitted, by no one more so than by Hueppe 

 and Gruber. In this I am not referring to changes which 

 are well known to occur in individual varieties in course of 

 many transferences, e.g. the gradual decrease or increase in 

 rapidity with which the gelatine is liquefied, or the differences 

 that can be observed in subcultures through many trans- 

 ferences as regards the more or less distinct alteration in the 

 formation of a pellicle on gelatine or on broth, &c., but I 

 am referring to pronounced differences present from the 

 outset on the different commas of different stock, and per- 

 sisting for many generations unaltered. 



For the object of demonstrating in a rapid manner the 

 presence of the cholera vibrios in the evacuations, even when 

 present in very small numbers, the method of Dunham is 

 the best : a flake or a loopful of the dejecta or contents of 

 the ileum is placed in a watery solution of pure peptone 

 I per cent., common salt o'5 per cent. After incubation at 

 37° C. already after 10-12 hours, better after 16-24 hours, 

 greater or lesser turbidity (according to the number of 

 comma bacilli present in the original intestinal material) is 



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