STRAINS OF PATHOGENIC BACTERIA 127 



tion and oscillation, and giving much the same growths upon 

 puncture of gelatine, while in even so minute a characteristic 

 as the arrangement of the cilia Lomer's method showed no 

 difference between No. 1 and the type. (It is not stated how 

 the others appeared under this treatment.) But there were 

 differences of rate of growth on potatoes, in gelatine, potato- 

 juice-gelatine, and broth, differences also in the intensity of 

 colour of potato cultures, differences in the effect of the bacilli 

 upon media to which aniline dyes had been added, and the 

 result on inoculations, which were far from complete, show 

 that on the whole No. 1 was less virulent for mice than in the 

 type Eberth-Gaffky bacillus. From these differences Cassedebat 

 concludes that he is dealing with pseudo-typhoid forms, and 

 that the results of the bacteriological examination of water must 

 be received with very great caution, if they are to be accepted 

 at all. I have already shown that the Eberth-Gaffky bacillus 

 is capable of very considerable modifications, is most susceptible 

 to change of medium, etc., and here, again, rather than accept 

 Cassedebat's conclusions, I would hold that the more satisfactory 

 explanation of his facts is that he dealt with races — natural and 

 fairly permanent races— modifications of the type bacillus of 

 typhoid. 



Turning now to cholera and its spirillum, it is already a 

 well-known fact — to which attention was, I believe, first called 

 by Zaslein x — that cultures of the spirillum derived from 

 simultaneous epidemics in different localities present recognizable 

 differences — differences in tint, in rate of growth, in power of 

 liquefying gelatine, etc. So there are those who declare that from 

 the appearance of a culture they can state its origin, whether from 

 Cairo or from Berlin, from Naples or Massowah, from Palermo 

 or Marseilles. It has, however, been left to Surgeon-Major 

 Cunningham to give the most remarkable example of these 

 differences. 2 At the beginning of 1890 three of the principal 

 hospitals in Calcutta contained cases of cholera, not differing 

 from one another in symptoms or virulence, all giving abundance 

 of cultivable spirilla, but these not of one but of three " species." 

 Later, other cases were observed, in all sixteen, and from these 



1 Zaslein, Deutsche med. Zeitung, ix., 1888, 759 and 771. 

 8 D. D. Cunningham, Scientific Memoirs by Medical Officers of the Army 

 of India, Part VI., 1891, p. 1. 



