[De epidemia et peste]

is not pure according to Avicenna in the second Fen of the first. When therefore the air putrefies, and begins to putrefy the humor that is surrounded by the heart, because it approaches it more closely, as the Prince a title often given to Avicenna says in the second Fen of the first, second doctrine, first summa, first chapter, and according to this way epidemics are generated, and very bad diseases such as anthrax, carbuncles, and the like. Sometimes an epidemic also comes in cold weather, and in such weather, humors are compacted, and the necessary resolutions of bad humors are not made; rather, they are retained. And these things happen especially in a sterile time with an abundance of fruits, and thus full and sanguine people are more infirm and destroyed. Whence Haly Haly Abbas, Persian physician (d. 994) on the royal disposition, book one, chapter sixteen: "They fear the coming of pestilential diseases most, whose complexion is hot and moist, and boys and adolescents, since a hot and moist complexion dominates them more than others." And he adds why it is necessary for them to multiply bloodletting and increase the use of things that refrigerate and dry. Also, those who are replete during such a time are accustomed to dying and falling ill more frequently, since they have pores blocked by gross and viscous humors. For the viscosity of the humors, and their grossness, and their superabundance are causes of blockage, as stated in the second book of the Tegni Galen's Art of Medicine, commentary: "Humid at the same time," etc. And blockage is a cause of putrefaction and consequently of fever, according to the third book of the Tegni, commentary: "For they carry..." If it happens so, therefore, fevers are generated in them, and consequently epidemic diseases, because in such a time, other fevers are rarely generated except for epidemic ones. Here it follows clearly that excessive, new repletion must be avoided. It follows secondly that excessive repletion must be reduced with an appropriate laxative or bloodletting. It follows thirdly that foods