the Middle Ages entertained a
doubt, was general among the people; yet in modern times surgeons have
filled volumes with partial controversies on this subject. The whole
language of antiquity has adapted itself to the notions of the people
respecting the contagion of pestilential diseases; and their terms were,
beyond comparison, more expressive than those in use among the moderns.

Arrangements for the protection of the healthy against contagious
diseases, the necessity of which is shown from these notions, were
regarded by the ancients as useful; and by man, whose circumstances
permitted it, were carried into effect in their houses. Even a total
separation of the sick from the healthy, that indispensable means of
protection against infection by contact, was proposed by physicians of
the second century after Christ, in order to check the spreading of
leprosy. But it was decidedly opposed, because, as it was alleged, the
healing art ought not to be guilty of such harshness. This mildness of
the ancients, in whose manner of thinking inhumanity was so often and so
undisguisedly conspicuous, might excite surprise if it were anything more
than apparent. The true ground of the neglect of public protection
against pestilential diseases lay in the general notion and constitution
of human society--it lay in the disregard of human life, of which the
great nations of antiquity have given proofs in every page of their
history. Let it not be supposed that they wanted knowledge respecting
the propagation of contagious diseases. On the contrary, they were as
well informed on this subject as the modern; but this was shown where
individual property, not where human life, on the grand scale was to be
protected. Hence the ancients made a general practice of arresting the
progress of murrains among cattle by a separation of the diseased from
the healthy. Their herds alone enjoyed that protection which they held
it impracticable to extend to human society, because they had no wish to
do so. That the governments in the fourteenth century were not yet so
far advanced as to put into practice general regulations for checking the
plague needs no especial proof. Physicians could, therefore, only advise
public purifications of the air by means of large fires, as had often
been practised in ancient times; and they were obliged to leave it to
individual families either to seek safety in flight, or to shut
themselves up in their dwellings