t his person, either during
his illness or after death?--Or is it, on the other hand, a disease
with the appearance and progress of which sick persons, individually
or collectively, have no influence, the sole cause of its presence
depending on unknown states of the atmosphere, or on terrestrial
emanations, or on a principle, _aura_, or whatever else it may be
called, elicited under certain circumstances, from both the earth and
air?--In the one case we have what the French, very generally I believe,
term _mediate_ and _immediate_ contagion, while the term _infection_
would seem to be reserved by some of the most distinguished of
their physicians for the production of diseases by a deteriorated
atmosphere:--much confusion would certainly be avoided by this adoption
of terms.[1] Now it is evident, that incalculable mischief must arise
when a community acts upon erroneous decisions on the above questions;
for, if we proceed in our measures on the principle of the disease not
being either directly or indirectly transmissible, and that it should,
nevertheless, be so in fact, we shall consign many to the grave, by
not advising measures of separation between those in health, and
the persons, clothes, &c., of the sick. On the other hand, should
governments and the heads of families, act on the principle of the
disease being transmissible from person to person, while the fact may
be, that the disease is produced in each person by his breathing the
deteriorated atmosphere of a certain limited surface, the calamity in
this case must be very great; for, as has happened on the Continent
lately, cordons may be established to prevent flight, _when flight, in
certain cases, would seem to be the only means of safety to many_; and
families, under a false impression, may be induced to shut themselves
up in localities, where "every breeze is bane."

[Footnote 1: As medical men in this Country employ the word _infection_
and _contagion_ in various senses, I shall, generally substitute
_transmissible_ or _communicable_, to avoid obscurity.]

Hence then the importance, to the state and to individuals, of a rigid
investigation of these subjects. It is matter of general regret, I
believe, among medical men, that hitherto the question of cholera has
not always been handled in this country with due impartiality. Even
some honest men, from erroneous views as to what they consider "the
safe side" of the question, and forgetting that the safe side