this Description of _Thucydides_,
dwells much upon it[20]. _Aristotle_ makes it one of his[21]
_Problems_, How the _Plague infects_ those who approach to the Sick. And
what is of more Consequence, _Galen_ himself is very clear in it[22];
for he has these words: +hoti syndiatribein tois loimottousin
episphales, apolausai gar kindynos, hosper psoras tinos+, _&c. that it
is unsafe to be about those, who have the Plague, for fear of catching
it, as in the Itch_, &c. Indeed this is a thing so evident, that we find
it at present the current Opinion of all Mankind, a very few Persons
only excepted, who have distinguished themselves by their Singularity in
maintaining the opposite Sentiment. And it is something strange that any
one should make a Question of a thing so obvious, which is proved
sufficiently by one Property only of the Disease, that whenever it
seizes one Person in a House, it immediately after attacks the greatest
part of the Family. This Effect of the _Plague_ has been so remarkable
at all times, that whoever considers it well, cannot possibly, I think,
have any Doubt remaining, or require any stronger Argument to convince
him, that the Disease is infectious. For this very reason the
_Small-Pox_ and _Measles_ are generally allowed to be _contagious_;
because it is observed, that when either of these Diseases is got among
a Family, it usually seizes successively the greatest part of that
Family, who have not had it before: at least if such in the Family hold
free Communication with the Sick. And by the same Argument the _Plague_
must be concluded to be infectious likewise. It cannot be pretended,
that this is occasioned in the _Plague_ from this only, that the sound
Persons are render'd more than ordinarily obnoxious to the unhealthy
Air, or whatever be the common Cause of the Disease, by being put into
fear and dispirited, upon seeing others in the same House taken sick:
For if this were the Case, _Children_, who are too young to have any
Apprehensions upon this Account, would escape better than others, the
contrary of which has been always experienced.

IT is true, some have not been attacked by the Disease, though
constantly attending about the Sick. But this is no Objection against
what is here advanced: for it is as easily understood how some Persons,
by a particular Advantage of Constitution, should resist Infection, as
how they should constantly breath a noxious Air without hurt. An odd
Observation of _Die