There has also come down to us a prescription called _Pillulae Magistri Michaelis Scoti_.[229] It enumerates about a dozen ingredients and the scribe has added an extravagant commendation of its healing powers. Mineral medicines were evidently not in fashion in those days; for the recipe speaks only of simples derived from herbs of different kinds. It is to be observed that this agrees exactly with the practice of Salerno, as the Materia Medica of that school was chiefly drawn from the botany of Dioscorides afterwards expounded by Ibn Beithar of Malaga, the great Moorish authority on the healing virtues of plants. There is no reason then to doubt the truth of the title which ascribes the prescription for these pills to Michael Scot. It is in any case a curious relic of early medical practice. It is possible that the great plague which fell upon Palermo at the time of Frederick’s marriage may have been, in part at least, the occasion of that interest which both the Emperor and his astrologer took in the healing art. These epidemics, which in several of their most fatal forms are now only known by tradition, were the dreaded scourge of the Middle Ages; their prevalence being no doubt due to the rude and insanitary habits of life which were then universal. We read of another infectious sickness which attacked Frederick and his crusaders when they were on the point of sailing from Brindisi in 1227. The season was one of terrible heat, so great indeed that one chronicle says the rays of the sun melted solid metal! Lying in the confinement of their galleys on an unhealthy coast the troops suffered severely. At last rain fell, but immediately poisonous damps arose from the steaming soil, and the plague began to show itself. Two bishops and the Landgrave of Thuringia were among the victims of the pestilence, and very many of the crusaders died. Frederick himself ran considerable risk of his life. Against the advice of his physician he had exposed himself to the sun in the course of his journey to Brindisi. After three days with the fleet he was obliged to return on account of the state of his health, when he at once went to the waters at Pozzuoli, which proved a successful cure. Michael Scot must have entered into these affairs with a large concern and responsibility for his master’s health, and we shall think much of the importance and consequence he enjoyed at this time when we remember that the chief object of his care as a physician was the life of one on whom interests that were more than European then depended. CHAPTER VIII THE LAST DAYS OF MICHAEL SCOT