He defines an acute disease as "a helpful effort made by Nature to drive out of the body or system, in every way possible, the morbific material." As regards the latter he makes the following remarks:—
Certain diseases are caused by particles which are disseminated
throughout the atmosphere, which possess qualities that are
antagonistic to the humors of the body, and which—when once
they gain an entrance into the system—become mingled with the
blood and thus are distributed throughout the entire organism.
Certain other diseases owe their origin to fermentations or putrefactions
of the humors, which fermentations vary in their nature—in
some cases the humors being excessive in quantity, while in
others they are bad in quality; and in either event the body finds
itself incapable of first assimilating them and then excreting them—a
state of affairs which cannot continue beyond a certain length
of time without producing further harmful effects.
According to Sydenham the fever, in the acute diseases,
assists Nature by separating from the general (total) mass
of the blood those particles which have undergone putrefaction
or have been rendered unassimilable. Then they
are driven out of the body by the route of the sweat-glands,
by diarrhoea, by eruptions upon the skin, etc. On the other
hand, in chronic diseases the morbific material is not of
such a nature as to produce fever, which is a mechanism
for securing complete purification. It is therefore deposited
in one part or another of the body where no force exists
which is capable of ejecting it; or its final transformation
is not completed until after the lapse of a long period of
time.
In some of Sydenham's writings one is occasionally surprised to find teachings which seem to be strongly at variance with the advice which he was so fond of giving—namely, that physicians should be careful not to set up hypotheses which are not based upon observed facts. A conspicuous instance of such a disregard of his own rule may be found in his setting up of a pathological process to which he gives the name of "inflammation of the blood." This process, he maintains, is the active cause of quite a large number of diseases, especially those of an epidemic
