The term intermittent is applied to that kind of fever which consists of a succession of paroxysms, between each of which there is a distinct and perfect decline of fever symptoms. Different names have been applied to this fever, according to the distance of time observed between the periods of its return. When it comes on within the space of twenty-four hours, it is called a quotidian; when it returns every other day, it is called a tertian; and when it attends on the first and fourth day, it is named a quartan ague. That under the tertian type is most apt to prevail in the spring, and the quartan in autumn. Intermittents often prove obstinate, and are of long duration in warm climates; and they not unfrequently resist every mode of cure, so as to become very distressing to the patient; a fact, to which the writer can bear testimony from personal experience. It is very generally acknowledged, that marsh exhalations, or the effluvia arising from stagnant water, when acted upon by heat, are the most frequent exciting causes of ague. A low diet, great fatigue, and the sudden disappearance of eruptions, have been ranked among the exciting causes of intermittents. Some persons imagine this fever may be communicated by contagion; but this supposition is by no means consistent with general observation. One peculiarity in this fever is, its great susceptibility of a renewal from very slight causes, as from the prevalence of an easterly wind, or from the repetition of the original exciting agency. It would appear, likewise, that a predisposition is left in the habit, which favours a return of the complaint.