The continual fevers are allied to each of the intermittents; thus, to the true tertian is allied the causus or ardent fever; to the quotidian, that fever which has a paroxysm every day, but does not terminate in a complete freedom from fever; and, in like manner, to the quartan, that which has an exacerbation every fourth day. For the true causus has all the other characteristics of the tertian, and differs from it only in not commencing with a rigor, nor ending in a complete remission of the fever. The continual fever which has an exacerbation every day, possesses all the other characteristics of a quotidian, except that it does not terminate in a perfect apyrexy. In like manner, the continual fever which has an exacerbation every fourth day, but does not terminate in a complete apyrexy, is allied to the quartan. A continual fever, therefore, is one which does not terminate in any interval from fever until it is altogether resolved. But when it evinces no remission, it is, indeed, of the same class as the ardent fevers, but differs from them in acuteness. * * * * * COMMENTARY. Hippocrates has stated the alliance between the intermittent and continual fevers. (Epidem., Op. Galeni, ed. Basil, v, p. 362.) In his report of the epidemical diseases of a certain season, he mentions that the continual fevers (συνεχεῖς) were distinguished by an exacerbation every alternate day, after the manner of tertians, and that they were attended with ardent symptoms. He also remarks their tendency to terminate in dysenteries, lienteries, and tenesmus. Galen marks a distinction between the continual fever (συνεχῆς) and the synochus, which it is necessary that the reader should particularly attend to. He remarks that there are three varieties of intermittents: the quotidian, which arises from putrid phlegm; the tertian, from yellow bile; and the quartan, from black bile. Of continual fevers, arising from yellow bile, there are two species; the one being called synochi, and consisting of one paroxysm from beginning to end; and the other, to which the generic appellation continual (συνεχεῖς) is particularly applied, and which consists of a number of particular paroxyms. Of the continual fevers, some assume the tertian type, having a remission of the fever every alternate day; some the quotidian, and have a remission every day; and others, of rare occurrence, resemble the quartans, in having remissions after an interval of three days. (De Diff. Feb. ii, 2.) In another place he says of synochous fevers that they consist of two varieties, the one arising from an ebullition of the blood, and being produced by the conversion of ephemerals; and the other arising from putrefaction of the blood in persons who are gross and plethoric. (Meth. Med. ix.) Aëtius treats of continual fevers (συνεχεῖς) in nearly the same terms as our author, and distinguishes them from the synochi.