Vitiated air is one of the most subtile and powerful of poisons, and it
seems to affect soldiers more than any other class of persons, and its
consequences have been commented upon by most of the military
writers,--from Xenophon among the Greeks, Vegetius among the Romans, down
to those of the present time. Cavalry horses have been observed to suffer
deterioration and death from the same cause.
Ague and fever, states Dr. Johnson, "two of the most prominent features of
the malarious influences, are as a drop of water in the ocean when
compared with the other, but less obtrusive, but more dangerous maladies
that silently disorganize the vital structure of the human fabric under
the influence of this deleterious and invisible poison."
One fourth of the sailors of the English navy are sent home invalided
every year, and one tenth of them die from the effects of foul air of
their cabins. "Two thirds of the pulmonary diseases which desolate England
are induced by this cause." Baudelocque long ago pointed out its
influences in the etiology of scrofula.
It is really the same influence observed by Magendie, and not contradicted
to the present day, that putrid blood, brain, bile, or pus, when laid on
flesh wounds, produce in animals, after a longer or shorter interval,
vomiting, languor, and death. The same results and phenomena are observed
in the inspiration of bad air; the most terrible forms of fever arise from
the overcrowding of people in confined and limited spaces. Most of the
zymotic diseases enter by the lungs, which are the principal absorbing
agents.
The breathing in of foul air, loaded with perceptible and putrid animal
and vegetable emanations, gives rise to those zymotici, the ideas of which
originated with Hippocrates, and to which the distinguished Liebig has
since given form and prominence.
Not only is animal life disturbed and destroyed, but we observe that
vegetables even are affected by the same or similar causes; that they are
extremely susceptible of impurities in the air, and that the rapidity and
vigorous appearance of their growth are affected whenever there is very
slight modification in the healthy proportions of the atmosphere. Again,
we see how seeds, when placed in elementary oxygen, germinate with extreme
rapidity, and soon decay, thus indicating how the presence of nitrogen in
the natural air restrains the force of the other element.