Taking another branch of the same subject, the causes of zymotic
diseases being traced to controllable sources, he said: Drs. Klebs and
Crudelli allege that malarial fever arises from germs present in the
soil and which float over the air of marshes; and that by treating with
water the soil of a fever-haunted marsh of the Campagna the germs of
this organism could be washed out; and that the water containing the
organisms thus obtained, introduced into the circulation of a dog,
produced ague more or less rapidly, and more or less violent, according
to the numbers in which the organisms were present in the water.

This theory, no doubt, agrees with certain well-known facts. In a
tropical climate, if soil which has been long undisturbed, or the soil
of marshy ground, be turned up, intermittent fever is almost certain to
ensue. In illustration of this, I recollect that at Hong Kong the troops
were unhealthy, and a beautiful position on a peninsula exposed to the
most favorable sea-breezes was selected for a new encampment. The troops
were encamped upon this spot for some time to test its healthiness,
which was found to be all that could be desired. It was then resolved to
build barracks. As soon as the foundations were dug, fever broke out.

As an instance of this nearer home, I may mention that last winter at
Cannes, in the south of France, some extensive works adjacent to the
town were begun which required a large quantity of earth to be moved.
The weather was exceptionally warm; an outbreak of fever occurred among
the workmen, of whom fifteen died. This fever was attributed to the
turning up of the soil.

If a strong solution of quinine be let fall in the water containing
these organisms they at once die; the efficacy of quinine as a
preventive of this form of fever would therefore not be inconsistent