Medical Officers of the Army of India.
4 1
a traveller who had just arrived from Hamburg, where the disease was prevalent
in epidemic form, died of cholera in the isolation ward of the hospital in Koblenz.
During the period between the first and fourth of September, five more attacks
occurred in the persons of two attendants, who had waited on the deceased, the
washerwoman who had washed his clothes, and two sisters, of whom one was occu-
pied in the isolation ward, and with this the local diffusion of the disease ceased.
Now, in such instances, it appears clear that the originally imported case was
capable of giving rise to a certain number of secondary ones, but that these had no
such property, and that, consequently, no general diffusion of the disease fol-
lowed. But were the bodies of the sick the essential site of the development and
multiplication of the specific cause of the disease, there could be no satisfac-
tory explanation of this phenomenon, there could be no sufficient reason to account
or the fact that the secondary cases are less efficient than the primary ones.
On the theory that the specific cause of the disease is manufactured and multi-
plied within the bodies of the sick, we must, in order to account for such cases,
assume that whilst the primary cases came into direct or indirect relation
with a relatively large number of predisposed individuals, the secondary ones
failed to encounter any at all, or, in other words, that the primary cases were
distinguished from the secondary ones by possessing a specific peculiarity for
encountering predisposed individuals—a supposition the acceptance of which
implies a very free exercise of " the scientific use of the imagination."
But if we accept the view that the manufacture and multiplication of the
specific cause of the disease take place in the environment, we have no
longer any difficulty in finding a satisfactory explanation for such phenome-
na. The primary cases then come clearly to differ from the secondary ones
in their relation to the cause of the disease. They are certainly derived from
localities in which there can be no question that the specific cause of the
disease is being manufactured, and hence there can be no reason why they
should not be capable of importing a sufficient amount of it with them to give
rise to the disease in the persons of those with whom they come into direct
or indirect contact. But if the material which has been imported consists
simply of the elaborated poison, or if the locality do not provide conditions
favourable to the organisms which manufacture it, it is clear that the effects
following importation must cease with the expenditure of the amount which has
been imported, and therefore that any general diffusion of the disease must be
impossible. The primary cases are efficient because they come from a site
of manufacture of the specific cause of the disease, not because they suffer from
its. effects.
Professor von Pettenkofer, who has done more than any other observer to
further a really scientific knowledge of the conditions determining the incidence of
epidemic cholera, has once and for all time incontrovertibly demonstrated
the overweening importance of the environment in relation to prevalence of the
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