Book II PESTILENT FEVERBS 83

about the heart, and enormous putrefaction in the rest of the
body causes that. 'Then why is not the fever felt before it has
become hectic? Finally, his statement that, in these fevers,
the heart or its contents putrefies, seems strange.

For it would seem that the patient would die forthwith, see—
ing that this very delicate organ cannot support even erysipelas.
Vet it is obvious that the patient does not die forthwith, for the
majority of the plague—stricken $urvive over the fourth or seventh
day, and, what is more, many escape death, which certainly
does not seem possible if hectic fever has already been establish—
ed. Furthermore, why are not other hectic fevers also pesti—
lent when the fever has been established in the heart?  And if
the putrid vapors about the heart have reached the point where
they can cause hectic and established excess of heat within the
heart, it seems as though they could cause putrefaction also,
either in the heart itself or at least in its contents. But if this
is what occurs, then it seems that not one plague—stricken per—
son ought to survive. 'These, then, are the objections that I
have to make to the above—mentioned theories. And so I shall
not suppress the arguments which I had previous!ly thought
out, though I am ready to change my own opinion, if my theor—
ies prove to be less satisfactory.

I cleave then to the fundamental principles which I have
laid down for the nature of contagions, and hence I assert that
pestilent fevers differ from other putrid fevers in many respects;
first in their active principle; secondly in the substance or man—
ner of their putrefaction; and lastly, in the accidents that re—
sult and are peculiar to them. In fact, in other putrid fevers,
the principles and causes of putrefaction are either obstruc—
tion or plethora or &a malignant condition, be it quantitative or
qualitative, of the humors. I call these 'active principles',
because they are the causes that produce putrefaction by the
agency of loca! heat. But in pestilent fevers no one of these
factors is per se the cause and principle of the putrefaction.
For the humors in some individual may be in a normal condi—
tion, obstruction and plethora may be entirely lacking, and yet
the plague may be contraeted from another person.  Therefore
there must be present some other principle per se of that con—
tagion. Not that there is any reason why the above—named
conditions may not sometimes be present in addition, but they
are an accidental addition to the principle (primary agent) that