forth remained free
from the disease, although other houses with openings on the exposed sides
continued unhealthy.

The literature relating to periodical fevers contains nothing else so
interesting as the very ingenious article of Dr. J. H. Salisbury, on the
"Cause of Malarious Fevers," contributed to the "American Journal of
Medical Science," for January, 1866. Unfortunately, while there is no
evidence to controvert the statements of this article, they do not seem to
be honored with the confidence of the profession,--not being regarded as
sufficiently authenticated to form a basis for scientific deductions. Dr.
Salisbury claims to have discovered the cause of malarial fever in the
spores of a very low order of plant, which spores he claims to have
invariably detected in the saliva, and in the urine, of fever patients,
and in those of no other persons, and which he collected on plates of
glass suspended over all marshes and other lands of a malarious character,
which he examined, and which he was never able to obtain from lands which
were not malarious. Starting from this point, he proceeds, (with
circumstantial statements that seem to the unprofessional mind to be
sufficient,) to show that the plant producing these spores is always
found, in the form of a whitish, green, or brick-colored incrustation, on
the surface of fever producing lands; that the spores, when detached from
the parent plant, are carried in suspension _only in the moist exhalations
of wet lands_, never rising higher, (usually from 35 to 60 feet,) nor
being carried farther, than the humid air itself; that they most
accumulate in the upper strata of the fogs, producing more disease on
lands slightly elevated above the level of the marsh than at its very
edge; that fever-and-ague are never to be found where this plant does not
grow; that it may be at once introduced into the healthiest locality by
transporting moist earth on which the incrustation is forming; that the
plant, being introduced into the human system through the lungs, continues
to grow there and causes disease; and that _quinia_ arrests its growth,
(as it checks the multiplication of yeast plants in fermentation,) and
thus suspends the action of the disease.

Probably it would be impossible to prove that the foregoing theory is
correct, though it is not improbable that it contains the germ from which
a fuller knowledge of the disease and its causes will be obtained. It is
sufficient for