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.