In every case of this disease which came under my notice, there were evident remissions, or intermissions of the fever, or of such symptoms as were substituted for fever. I have long considered, with Mr. Senac, a _tertian_ as the only original type of all fevers. The bilious yellow fever indicated its descent from this parent disease. I met with many cases of regular tertians, in which the patients were so well on the intermediate days as to go abroad. It appeared in this form in Mr. Van Berkel, the minister of the United Netherlands. Nor was this mild form of the fever devoid of danger. Many died who neglected it, or who took the common remedies for intermittents to cure it. It generally ended in a remittent before it destroyed the patient. The tertian type discovered itself in some people after the more violent symptoms of the fever had been subdued, and continued in them for several weeks. It changed from a tertian to a quartan type in Mr. Thomas Willing, nearly a month after his recovery from the more acute and inflammatory symptoms of the disease. It is nothing new for a malignant fever to appear in the form of a tertian. It is frequently the garb of the plague. Riverius describes a tertian fever which proved fatal on the third day, which was evidently derived from the same exhalation which produced a continual malignant fever[30]. [30] De Febre Pestilenti, vol. xi. p. 93. The remissions were more evident in this, than in the common bilious fever. They generally occurred in the forenoon. It was my misfortune to be deprived, by the great number of my patients, of that command of time which was necessary to watch the exacerbations of this fever under all their various changes, as to time, force, and duration. From all the observations that were suggested by visits, at hours that were seldom left to my choice, I was led to conclude, that the fever exhibited in different people all that variety of forms which has been described by Dr. Cleghorn, in his account of the tertian fever of Minorca. A violent exacerbation on even days was evidently attended with more danger than on odd days. The same thing was observed by Dr. Mitchell in the yellow fever of Virginia, in the year 1741. "If (says he) the exacerbations were on equal days, they generally died in the third paroxysm, or the sixth day; but if on unequal days, they recovered on the seventh." The deaths which occurred on the 3d, 5th, and 7th days, appeared frequently to be the effects of the commotions or depression, produced in the system on the 2d, 4th, and 6th days. The remission on the third day was frequently such as to beget a belief that the disease had run its course, and that all danger was over. A violent attack of the fever on the 4th day removed this deception, and, if a relaxation had taken place in the use of proper remedies on the 3d day, death frequently occurred on the 5th or the 7th.