The first notice on this subject is due to a very celebrated teacher in Perugia, Gentilis of Foligno, who, on the 18th of June, 1348, fell a sacrifice to the plague, in the faithful discharge of his duty. Attached to Arabian doctrines, and to the universally respected Galen, he, in common with all his contemporaries, believed in a putrid corruption of the blood in the lungs and in the heart, which was occasioned by the pestilential atmosphere, and was forthwith communicated to the whole body. He thought, therefore, that everything depended upon a sufficient purification of the air, by means of large blazing fires of odoriferous wood, in the vicinity of the healthy as well as of the sick, and also upon an appropriate manner of living, so that the putridity might not overpower the diseased. In conformity with notions derived from the ancients, he depended upon bleeding and purging, at the commencement of the attack, for the purpose of purification; ordered the healthy to wash themselves frequently with vinegar or wine, to sprinkle their dwellings with vinegar, and to smell often to camphor, or other volatile substances. Hereupon he gave, after the Arabian fashion, detailed rules, with an abundance of different medicines, of whose healing powers wonderful things were believed. He had little stress upon super-lunar influences, so far as respected the malady itself; on which account, he did not enter into the great controversies of the astrologers, but always kept in view, as an object of medical attention, the corruption of the blood in the lungs and heart. He believed in a progressive infection from country to country, according to the notions of the present day; and the contagious power of the disease, even in the vicinity of those affected by plague, was, in his opinion, beyond all doubt. On this point intelligent contemporaries were all agreed; and, in truth, it required no great genius to be convinced of so palpable a fact. Besides, correct notions of contagion have descended from remote antiquity, and were maintained unchanged in the fourteenth century. So far back as the age of Plato a knowledge of the contagious power of malignant inflammations of the eye, of which also no physician of the Middle Ages entertained a doubt, was general among the people; yet in modern times surgeons have filled volumes with partial controversies on this subject. The whole language of antiquity has adapted itself to the notions of the people respecting the contagion of pestilential diseases; and their terms were, beyond comparison, more expressive than those in use among the moderns.