The fever at Rouen which Le Cat specially described to the Royal Society was an outbreak from the end of November, 1753, to February, 1754. This outbreak was only one of a series; but as it attacked a great number of persons of distinction and made great havock among them, it attracted unusual notice and was regarded as something new, the rumour spreading over Europe that Rouen had been visited by plague. The same fever, however, had occurred there in previous years; and allied forms of sickness, of the same gangrenous character, including gangrenous sore-throat, could be traced back for twenty or thirty years. It will suffice to mention of these the malignant fever which appeared in 1748 and continued in 1749, 1750 and 1751. There was a fixed pain in the head, pain about the heart, a low fever with delirium, often miliary eruptions, continual faint sweating, drowsiness, scanty or suppressed urine, abdominal distension. After death the stomach was found “inflamed” at places, as well as the small intestine. In some cases there were ulcerations which almost penetrated the coats. The lungs were engorged with blood. In one case, of a young woman aged twenty, the mesentery was filled with obstructed glands and the intestines mortified in different places. In another, almost the whole mesentery was mortified and there was an anthrax or carbuncle at the upper fore part of the armpit. At the same time some cases of smallpox, with miliary eruption, also had ulcerations of the stomach, with inflammatory spots on other parts of it and of the intestine, the mesenteric glands being enlarged and hard. Some of the cases at the Hôtel Dieu in 1750 were traced to infection from bales of horse-hair; but the type of the disease in those cases did not differ essentially from that of other cases. Some rapidly fatal cases in the winter of 1752-53 had suppurative inflammation about the heart. (In 1739 there had been deaths from continued fever at the Hôtel Dieu, after an illness of six or seven days, marked by frequent faintings, small abscesses being found after death in the substance of the heart near the auricles.) The fever among the upper classes in the winter of 1753-54 was marked, in its most mortal form, by lowness, continued fever, pain in the head, cough, sore-throat, nausea, dry black tongue, delirium, sweats, stupor, some oppression of the heart, spitting of blood, sometimes swelling of the belly, these symptoms being followed often by miliary eruption, and sometimes by a slight flux with blood. Many were affected with a dejection of spirits, and with a feeling of terror which made them tremble at the ordinary sound of the voice. The fever ran a full course of thirty or forty days (the miliary eruption coming about the 21st day), while death usually ensued about the 25th.