He asserted boldly and with truth, "_that all epidemic diseases might become contagious_, _and all fevers epidemic_," which attentive observers of all subsequent ages have confirmed.
He delivered his sentiments on blood-letting with sagacity, as an experienced physician; yet he was unable, as may be imagined, to moderate the desire for bleeding shown by the ignorant monks.

He was averse to draw blood from the veins of patients under fourteen years of age; but counteracted inflammatory excitement in them by cupping, and endeavoured to moderate the inflammation of the tumid glands by leeches.

Most of those who were bled, died; he therefore reserved this remedy for the plethoric; especially for the papal courtiers and the hypocritical priests, whom he saw gratifying their sensual desires, and imitating Epicurus, whilst they pompously pretended to follow Christ.

He recommended burning the boils with a red-hot iron only in the plague without fever, which occurred in single cases; and was always ready to correct those over-hasty surgeons who, with fire and violent remedies, did irremediable injury to their patients.

Michael Savonarola, professor in Ferrara (1462), reasoning on the susceptibility of the human frame to the influence of pestilential infection, as the cause of such various modifications of disease, expresses himself as a modern physician would on this point; and an adoption of the principle of contagion was the foundation of his definition of the plague.