These are the rules to be observed by such as are in health, that are only apprehensive of the cause. We next proceed to the cure of fevers, which is a kind of disease, that affects the whole body, and is the most common of all. Of these one is a quotidian, another a tertian, and a third a quartan. Sometimes some fevers also return after a longer period, but that seldom occurs. With regard to the former, they are both diseases in themselves, and a cure for others.

But quartan fevers are more simple. They begin commonly with a shuddering; then a heat breaks out; after the paroxysm is over, the patient is well for two days. So that it returns upon the fourth day.

Of tertians again there are two kinds. One of them both beginning and ending like the quartan; with this difference only, that there is one day’s intermission, and it returns upon the third. The other kind is much more fatal, which indeed returns upon the third day, but of forty-eight hours, thirty-six are occupied by the fit (and sometimes either less or more,) nor does it entirely cease in the remission; but is only mitigated. This kind most physicians call semitertian[ BB ].

But quotidians are various, and different in their appearances. For some of them begin with a heat, others with a coldness, others with a shuddering. I call that a coldness, when the extremities of the limbs are chilled; a shuddering, when the whole body trembles. Again, some end, so as to be followed by an interval quite free from indisposition; others so, as that though the fever somewhat abates, yet some relicks remain, till another paroxysm comes on; and others often remit little or nothing, but continue as they began. Some again are attended with a very vehement heat, others more tolerable; some are equal every day, others unequal, and alternately milder one day and more severe another: some return at the same time the following day, others either later or sooner: some by the fit and the intermission take up a day and a night, some less, others more: some, when they go off, cause a sweat, others do not; and in some a sweat leaves the patient well, in others it only renders the body weaker: sometimes also one fit comes on each day, sometimes two or more. Whence it frequently happens, that every day there are several both paroxysms and remissions; yet so as that each of them answers to some preceding one. Sometimes too the fits are so irregular, that neither their durations nor intermissions can be observed. Nor is it true, which is alledged by some, that no fever is irregular, unless it arise from a vomica, or an inflammation, or an ulcer. For the cure would always be easier, if this were fact. For what is occasioned by the evident causes, may also proceed from the occult. Nor do those dispute about things, but words, who alledge, that when feverish paroxysms come on in different manners in the same distemper, these are not irregular returns of the fever, but new and different fevers successively arising. Which however would have no relation to the method of cure, though it were true. The intervals also are sometimes pretty long, at other times scarce perceptible.