Counsel Against the Plague

1479, and it most greatly offends men and places that have the ascendant afflicted by these constellations. But in more particular pestilences, the aforementioned poison arises from winds and malignant vapors, from lakes and marshes, and from earthquakes. ¶ From whatever cause it proceeds, it reigns principally in thick, swampy, foggy, and fetid air; and when it extends into thin air, it penetrates and kills more quickly. But it reigns first, and more often, and for a longer time in thick, hot, humid, and fetid air. Thick air. Some doctors say that the pestilential putrefaction begins first in thin air, but endures longer in thick air; I do not know how to prove the first part, seeing that experience shows us the contrary. Moreover, reason tells us that since the pure element cannot putrefy, but rather the mixture, the less it is mixed—as thin air is—the less apt it is for putrefaction. And therefore, it does not take hold of it unless the pestilential influence of the stars is continuing and increasing. But thick and foggy air putrefies easily, like thick, mixed, and stagnant water. Raymond holds this opinion: that when the plague comes from below, one should flee to high and thin air, but when When the plague begins from below, flee to high ground.