204 MICROBES, FERMENTS, AND MOULDS. 
searches, and the first idea which will occur to any 
unprejudiced micrographist, is that P. Ferrani is not 
really Koch’s comma bacillus, and consequently not 
the cholera microbe.* 
We have, in fact, already shown that numerous 
comma-shaped bacteria, or free cells, are found in 
water and in the human body, and that these may 
be easily confounded with the true comma bacillus 
when staining reagents and a very precise mode of 
culture are not employed. Ferran himself states that 
this staining process must not be used in the culture 
of P. Ferrani. Cornil has, however, shown that the 
true comma bacillus is not destroyed by methyl 
violet. Finkler had previously discovered in cholera 
nostras, which is not epidemic, a comma-shaped 
microbe resembling in many respects the one 
described by Ferran. Koch has shown that this 
microbe, as well as one of similar form found by 
Lewis in the saliva, does not act in cultures like the 
microbe of Asiatic cholera; Lewis’s microbe does not, 
like the cholera bacillus, liquefy gelatine. 
The precautions necessary for the sowings of 
culture liquids are so great that we may be permitted 
to doubt whether Ferran has always guarded.against 
error. Brouardel’s report shows, after a visit to 
* Onur criticism on the description and illustrations of Laveran’s 
marsh-fever microbe might be applied, word for word, to Ferran’s 
description and illustrations of the cholera microbe, which we have 
reproduced above. 
