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Scientific Memoirs by
conditions, and it would be strange indeed were it not to undergo important
modifications under totally different ones. The contents of the intestinal tract
most certainly do not normally represent a favourable environment to vibrionic
organisms, and equally certainly they come to do so under the influence of the
alterations which they undergo on the establishment of the choleraic condition,
but this is no proof whatever that the alteration which provides the favourable
environment is directly provided by the favoured schizomycetes. Even, according
to Koch, the epidemic diffusion of cholera necessarily implies a coincident epi-
demic diffusion of certain dyspeptic conditions permitting of the continued vitality
and activity of choleraic vibriones when they gain access to the intestinal tract.
Influenced by such considerations, I have hitherto maintained that there is
no sufficient evidence that choleraic vibriones have any causal relation to cholera
whatever, and, in doing so, I have departed from pure Pettenkoferianism ; but
of late I have become inclined to revert to the latter in an immaterially modified
form, and to allow of the probability that there may be a certain causal relation
between certain vibrionic schizomycetes and the disease. The accumulation of
evidence, indicative of the normal and almost constant association of vibrionic
organisms with the choleraic condition, renders it more and more difficult to re-
gard the phenomenon as a purely fortuitous one, or one solely dependent on
alterations in the nature of the intestinal contents viewed as an environment, and
cannot but suggest that the schizomycetes do play a definite rôle in giving rise
to the disease. But this does not in any way involve any abandonment of the
views which I have always maintained in regard to the incapacity of choleraic
vibriones to induce the disease as the simple result of their access to the intesti-
nal tract, and as to the supreme importance of local conditions on the elaboration
of the toxin upon the action of which the establishment of the choleraic condition
depends.
All that I am now prepared to grant is, that the normal presence of vibrionic
organisms of various species as a predominant and characteristic feature of the
contents of the intestinal tract during the choleraic condition does suggest the pro-
bability that vibriones as a group do really hold causal relation to the development
of that condition. Formerly, I was disposed to regard the phenomenon as one
solely dependent on the action of alterations on the intestinal contents, as an
environment, on the predominance of special forms, normally, and constantly
present in them,—as merely indicative of the action of alterations in the environ-
ment, occurring quite apart from any action whatever of vibrionic organisms on the
induction of such alterations, Now, however, I am inclined to allow of the prob-
ability that such organisms really do hold a definite causal relation to the induc-
tion of the conditions which convert the intestinal contents into a medium specially
favouring their multiplication. On the one hand, the normal predominance
of intestinal vibrionic organisms in the choleraic condition unequivocally suggests
the possibility that the association is not of a merely casual origin or dependent