(From thesame). An intermittent fever, is a febrile disease consisting of distinct attacks, with perfect freedom from fever in the intervals. Different names are given to this fever according to the periods of its return; if after twenty-four hours, a quotidian; if after forty-eight hours, a tertian; if after seventy-two hours, a quartan; after ninety-six hours, a quintan, or a pemptaeus. Such inter-mittents are, however, rare; and those with longer intervals have been styled erratic. Those are called autumnal which begin in August, and those vernal which begin in February.

Dr. Cullen places intermittent in the class pyrexiae, order febres; defining it fever arising from marsh miasma, consisting of many paroxysms; a total freedom from fever, at least an evident remission; returning with a marked exacerbation, and generally with shivering; having one paroxysm only in a day. He adds,"whoever will weigh what will be delivered concerning remittent fevers, and their distinction from continued fevers, strictly so called, will readily see why I have thought it necessary to change the character formerly given of intermittents as well as continued fevers." The latter he defines fevers having no intermission, nor arising from marsh miasma, but continuing only with slight remissions and exacerbations; having two exacerbations each day."he thinks that the no-sologists, Sauvages, Linnaeus, and Sagar, have not acted judiciously in instituting a separate order of remittents, as if they were altogether different from perfect intermittents; for those fevers called remittents arise from the same cause, viz. marsh miasma, as intermittents; each appears as an epidemic, in the same place, and at the same time of the year; each is cured exactly by the same remedies; and very often in the same subject, the same disease sometimes exhibits the intermittent, sometimes the remittent, type; diseases, therefore, so extremely alike with respect to their causes, mode of cure, and type, ought neither to be placed under a different order, or in different section."

The patient, though free from fever, is slightly indisposed the following day with chilliness and languor: he hath a weak and slow pulse, his urine is pale, and either deposits a sediment, or contains a small cloud suspended in it; the sediment is of a reddish colour, exactly resembling brick dust; the surface frothy, or covered with a pellicle. The beginning of autumnal intermittents is sometimes not very different from that of continual fevers. When weakly persons are the subjects, the intermissions are proportionally less distinct.

Obstinate intermittents often end in dropsies, or hectics from obstructed viscera. Vernal intermittents often require no assistance, and very rarely prove fatal.

Intermittents are distinguished by the very regular appearance of each stage of fever formerly described (see Febris); and the continuation of the paroxysm sometimes extends to twenty-two hours, the patient having scarcely two hours interval; but this chiefly happens when two diseases of this kind have attacked the patient at once, so that the fit of one comes closely on the conclusion of the former paroxysm. A single quotidian will, however, sometimes last eighteen or twenty hours.

In general it will be found that the longest paroxysms have the shortest intermissions; and the contrary; but the time of the paroxysms is occasionally anticipated or retarded. An increase of the interval, or rather a retarded paroxysm, shows the disease to be declining; while an anticipated attack is rather a sign that the disease is becoming a remittent or continued fever.

It is singular that intermittents rarely attack in the night. When the paroxysm anticipates, so as to come before eight, its next step is usually to the febrile period of the evening, previous to the usual day of its attack; and when it is retarded beyond eight or ten in the evening, the following attack is usually at eight in the morning following its accustomed day. Continued fevers are said to attack in the night, but we have generally found that the patient has complained in the evening, and that the fever has then formed, though the rigor has only taken place during the night, or rather about four in the morning.

The attack of intermittents is sometimes attended with the most alarming symptoms, such as syncope, apoplexy, a great load on the chest, with threatening suffocation, epileptic paroxysms or violent spasms, or a coldness, which increases till the patient sinks into torpor, soon followed by death. These are circumstances of peculiar danger, and require the most minute attention. The hot fit is also sometimes so violent as to be attended with delirium, and occasionally with rupture of the vessels, from the violence, in the language of Dr. Cullen, of the reaction. These circumstances require particular attention in the conduct of the cure.

Intermittents are sometimes complicated; that is, there may be two tertians, or two quartans, existing at the same time. The double tertian of authors, the duplicana of Linnaeus, consists of two tertians, returning each at their regular times, and thus attacking every day. The real disease is distinguished from a quotidian by the time of the attack, which in a tertian is about noon, by the shorter paroxysms; and by the fits of fever which occur on the alternate days resembling each other: while, if that on the succeeding is compared with the fit of the former day, some difference is observable. Another form of the double tertian is with two paroxysms in one day; and this kind is distinguished by the appellation of tertana duplicata. A triple tertian has also been observed, consisting of two paroxysms on each alternate day, and one only in the interval. This is the semitertiana of authors, the ter-tiana triplex of Sauvages. Tertians differ also in the degree of remission, when complicated in the manner already mentioned. Thus a double tertian, which returns daily, will have often the remission between the unequal and equal day; between the third and the fourth, for instance, more strongly marked; between the equal and unequal day less strongly.