[De epidemia et peste]

or hot and moist due to the excessive continuation of the southern winds, with turbulence of the air and its thickness and a multitude of clouds. Then, with good reason, pestilence comes, especially if there is a bad or malignant influence with these conditions, such as when Saturn is in its house, namely in Capricorn and Aquarius, just as it is now. For now, on the 25th of October in the year 1474, when this treatise was compiled, Saturn was in the twelfth degree of Capricorn, and similarly in Scorpio in its house on the same day, which works malignancy and maintains its evils, just as everyone does their own will in their own house, as is better seen elsewhere. Therefore, when these things concur, the epidemic becomes worse. For which reason Avicenna said in the fourth book that the beginning of all these things is forms from forms, that is, the influence of the planets and the constellations making necessary that whose event is unknown, etc. And it follows: "And it is necessary that the first cause is far, which are the celestial figures, and the near cause of that, which are the terrestrial dispositions." Whether, therefore, winds blow in excellence, or rains occur, or excessive dryness or coldness, through which the air is altered or corrupted, the cause of all these things is celestial influence. This is what Avicenna seems to say where mentioned above. It is certain, however, that sometimes the air putrefies from a lower root alone, or from unburied corpses, and an epidemic is generated. Note, however, that no matter how much the air's complexion is strained in its primary qualities, pestilential diseases are never generated until it putrefies. Nevertheless, some illnesses are generated from the straining of its qualities that do not deserve to be called epidemic. Note also that the air does not putrefy in itself by reason of itself, since it is a simple body, but by reason of the vapors mixed with it, because the air surrounding us