t of the bodies of a given number
of men, confined within a tent of a given dimension, raises the
temperature within the tent beyond the temperature of the common air
outside the tent. The ascent of moisture is thus encouraged, generally
by a change of temperature in the tent, and more particularly by the
immediate or near contact of the heated bodies of the men with the
surface of the earth. Moisture, as exhaled from the earth, is
considered by observers of fact to be a cause which acts injuriously on
health. Produced artificially by the accumulation of individuals in
close tents, it may reasonably be supposed to produce its usual effects
on armies. A cause of contagious influence, of fatal effect, is thus
generated by accumulating soldiers in close and crowded tents, under
the pretext of defending them from the inclemencies of the weather; and
hence it is that the means which are provided for the preservation of
health are actually the causes of destruction of life.

"There are two causes which more evidently act upon the health of
troops in the field than any other, namely, moisture exhaled direct
from the surface of the earth in undue quantity, and emanations of a
peculiar character arising from diseased action in the animal system in
a mass of men crowded together. These are principal, and they are
important. The noxious effects may be obviated, or rather the noxious
cause will not be generated, under the following arrangement, namely, a
carpet of painted canvas for the floor of the tent; a tent with a light
roof, as defense against perpendicular rain or the rays of a vertical
sun; and with side walls of moderate height, to be employed only
against driving rains. To the first there can be no objection: it is
useful, as preventing the exhalations of moisture from the surface of
the earth; it is convenient, as always ready; and it is economical, as
less expensive than straw. It requires to be fresh painted only once a
year."

The effect of crowding men together in close quarters, illy ventilated,
was shown in the prisons of Hindostan, where at one time, when the
English held sway, they had, on an average, 40,000 natives in
confinement; and this unfortunate population was every year liberated
by death in proportions varying from 4000 to 10,000. The annual average
mortality by crowded and unventilated barracks in the English army has
sometimes been enormous, as at Barrackpore, where it seldom fell far
short of one te