The estimation of cosmical influences, however, in the epidemy and pestilence, is well worthy of commendation; and Santa Sofia, in this respect, not only agrees with the most intelligent persons of the fourteenth and fifteenth centuries, but he has also promulgated an opinion which must, even now, serve as a foundation for our scarcely commenced investigations into cosmical influences.

Pestilence and epidemy consist not in alterations of the four primary qualities, but in a corruption of the air, powerful, though quite immaterial, and not cognoscible by the senses--( corruptio aeris non substantialis, sed qualitativa) in a disproportion of the imponderables in the atmosphere, as it would be expressed by the moderns.

The causes of the pestilence and epidemy are, first of all, astral influences, especially on occasions of planetary conjunctions; then extensive putrefaction of animal and vegetable bodies, and terrestrial corruptions (corruptio in terra): to which also bad diet and want may contribute.
Santa Sofia considers the putrefaction of locusts, that had perished in the sea and were again thrown up, combined with astral and terrestrial influences, as the cause of the pestilence in the eventful year of the "Great Mortality." All the fevers which were called forth by the pestilence are, according to him, of the putrid kind; for they originate principally from putridity of the heart's blood, which inevitably follows the inhalation of infected air.

The Oriental Plague is, sometimes, but by no means always occasioned by _pestilence_ ( ?), which imparts to it a character (_qualitas occulta_) hostile to human nature.

It originates frequently from other causes, among which this physician was aware that contagion was to be reckoned; and it deserves to be remarked that he held epidemic small-pox and measles to be infallible forerunners of the plague, as do the physicians and people of the East at the present day.
In the exposition of his therapeutical views of the plague, a clearness of intellect is again shown by Santa Sofia, which reflects credit on the age.