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Scientific Memoirs by
temporary and violent epidemics. It is, moreover, quite possible, especially if it
be taken into account that Koch's observations were limited to the cold season
in India, that in Europe his species is that of most frequent occurrence. At the
same time, however, facts are not wanting in regard to European observations
which, in the light of our present information, render it highly probable that in
Europe also different observers have really been dealing with distinct species, whilst
believing that they were occupied in the study of a single one only. It is only
on this supposition that it appears to be possible to account for the very con-
flicting statements which have from time to time been made in regard to many
points in the life-history of Choleraic Comma-Bacilli in Europe.
That such an experienced and skilful observer as Professor Hueppe, of
Prague, should have been mistaken in regard to his observations regarding the
formation of spores by Choleraic Comma-Bacilli, is from the outset improbable, and
it is much more likely that the discrepancy between his views and those of' many
other eminent observers is dependent simply on the fact that more than one
species was actually under observation. So, again, with regard to the discrepan-
cies between the statements which have been made by various observers in re-
gard to the capacity for growth of Choleraic Comma-Bacilli in acid media. As
will be shown presently, the different species present in Calcutta, differ conspicu-
ously from one another in this respect, so that Koch's original statements re-
garding the incapacity for growth of his species, under such conditions, may
quite possibly have been dependent on his actually having encountered a species
characterised by it, and that the contradictory utterances of various observers in
Europe on the same point, need not necessarily be regarded as due to imper-
fect observation. As more positive evidence of the existence of a multiplicity
of species in Europe, we have further Zäslein's observations regarding the
differ-ence presented by the Comma-Bacilli derived from simultaneous epidemics in
different localities—Genoa, Naples and Palermo—in Europe.*
Koch's discovery was so striking, and appeared to constitute such a step in
advance of any previous observation, that it is little to be wondered at that it
should have at first been assumed to imply more than it really did. There can
be no doubt that, as regards the vast majority of cases of cholera, Koch was
quite correct in maintaining that the presence of large numbers of Comma-
Bacilli in the intestinal contents, is a characteristic, and even so far diagnostic,
phenomenon of the disease; and it was not unnatural that the question of the speci-
- fic identity of the Commas present in different cases should at first have been
neglected in favor of investigations in regard to the constancy of their occur-
rence, and their possible pathogenic properties. In Europe, moreover, supplies
of choleraic materials are fortunately intermittent and scarce, so that conditions
are not there very favorable to comparative studies of the properties of the
* " Ueber die Varietäten des Koch'schen Komma-Bacillus " (Deutsche Med. Zeitung, 1888, Nos. 64
& 65).