46
Scientific Memoirs by
the necessary factors for the production of the specific cause everywhere
generally diffused, the phenomena indicating that communication with an
infected area appears in some cases to be unequivocally connected with the
local development of an epidemic would remain entirely incomprehensible.
But if, whilst refusing to accept the pure contagionist point of view that
the cause of cholera is manufactured within the bodies of the sick, and the
purely localist theory that the actual factors are universally diffused and only
req wire to be properly associated with certain local conditions in order to
secure the development of epidemics, an intermediate position be adopted,
no difficulty remains in finding a satisfactory explanation of the actually
existing phenomena. If the manufacture of the specific cause of the dis-
ease be carried on not within the bodies of the sick, but in the environment
and only there under certain conditions, the want of any close correspondence
between communication with infected localities or actual introduction of cases
of the disease and the occurrence of epidemic diffusion is no longer incompre-
hensible, and, on the other hand, if the actual factors of the specific cause
be not normally universally diffused, there is certainly no difficulty in com-
prehending why communication with sites in which they are present should be
capable of influencing their dissemination.
Up to the present time there has been no satisfactory laboratory demon-
stration that the specific cause which gives rise to the initial symptoms of
cholera is manufactured and multiplied within the bodies of the sick, and there
are very many epidemiological phenomena which appear to indicate unequivo-
cally that the manufacture takes place elsewhere, so that there would appear
to be no good ground for persisting in endeavouring to account for epidemics
on the contagionist point of view, or for insisting in seeking for the factors
of the poison within the bodies of those who suffer from it. If we accept the
view that the poison is manufactured in the environment, but only manufac-
tured there under certain circumstances, we have no difficulty in finding an
explanation of many phenomena, which are utterly inexplicable if we insist on
regarding the bodies of the sick as the essential site of manufacture and, on
the other hand, we have no difficulty in accounting for the very phenomena on
which the contagionist theory is founded. Cases, like those previously alluded to
as occurring in Stuttgart and Koblenz, cease to be incomprehensible if we allow
that the actual cause of disease is developed in the environment, for the phe-
nomena are precisely those which would naturally attend the importation of a
limited amount of poison into a locality, or the introduction, not merely of an
already elaborated poison, but also of a certain number of the factors producing
it, into a locality in which the conditions permitting of manufacture were not
present. Any one in coming from an area in which the opium poppy is
cultivated may carry along with him either a certain quantity of opium alone, or
a certain amount of opium together with a certain quantity of the seeds of the
poppy. If he introduce the opium alone into the place to which he proceeds, it