Sec. 254. Intermitting Fevers are distinguished into those of Spring and Autumn. The former generally prevail from February to June: the latter are those which reign from July to January. Their essential Nature and Characters are the very same, as they are not different Distempers; though the various Circumstances attending them deserve our Consideration. These Circumstances depend on the Season itself, and the Constitution of the Patients, during such Seasons. The Spring Intermittents are sometimes blended with an inflammatory Disposition, as that is the Disposition of Bodies in that Season; but as the Weather then advances daily into an improving State, the Spring Fevers are commonly of a shorter Duration. The autumnal Fevers are frequently combined and aggravated with a Principle of Putrefaction; and as the Air of that Season rather degenerates, they are more tedious and obstinate. Sec. 255. The autumnal Fevers seldom begin quite so early as July, but much oftner in August: and the Duration to which they are often extended, has increased the Terror which the People entertain of Fevers that begin in that Month. But that Prejudice which ascribes their Danger to the Influence of August, is a very absurd Error; since it is better they should set in then than in the following Months; because they are obstinate in Proportion to the Tardiness, the Slowness of their Approach. They sometimes appear at first considerably in the Form of putrid Fevers, not assuming that of Intermittents till some Days after their Appearance: but very happily there is little or no Danger in mistaking them for putrid Fevers, or in treating them like such. The Brick-coloured Sediment, and particularly the Pellicle or Film on the Surface of the Urine, are very common in autumnal Intermittents, and are often wanting in the Urine of putrid Fevers. In these latter, it is generally less high coloured, and leaning rather to a yellow, a kind of Cloudiness is suspended in the Middle of it. These also deposite a white Sediment, which affords no bad Prognostic. Sec. 256. Generally speaking, intermitting Fevers are not mortal; often terminating in Health of their own Accord (without the Use of any Medicine) after some Fits. In this last Respect Intermittents in the Spring differ considerably from those in the Fall, which continue a long Time, and sometimes even until Spring, if they are not removed by Art, or if they have been improperly treated. Quartan Fevers are always more obstinate and inveterate than Tertians; the former sometimes persevering in certain Constitutions for whole Years. When these Sorts of Fevers occur in boggy marshy Countries, they are not only very chronical or tedious, but Persons infested with them are liable to frequent Relapses.