Problemata Aristotelis

Why do human bodies feel themselves more sluggish and weaker when southern winds blow? Is it because much humor then overflows from a little, which warmth has forced to melt? From that, a heavy humor is stirred by a light breeze. Add that our strength is stored in the joints, which are accustomed to be loosened by southern winds. This is evident from their creaking, which, having been glued together before, then relax and resolve. For the tenacious humor which is placed in the joints, as if congealed, does not allow us to be moved; thus, when it is overly moistened, it does not allow [the limbs] to be tensed.

Why is it that during the summer one labors more with ill health, but during the winter those who labor die more easily? Is it because the heat which is held inside during the winter due to the density of the body aids it a little, and the labor of work, which is undertaken more during that time, cannot digest the humor waste products? Therefore, it is necessary that the origin of the evil be strong. When this is the case, it is reasonable that a pernicious disease urges it on. Conversely, in the summer, since the whole body is cooled and resolved by the rays and is impatient of labor, it seems necessary that more diseases arise, specifically due to fatigue and the rawness of foods. For new fruits are then present, yet nature does not allow them to be so strong; therefore, the ability to assist in these matters is given more easily.

Why does death occur most especially during the one-hundred-day period after either solstice? Is it because both the vehemence of heat and of cold extends until then, which can bring disease and destruction to the infirm?

Why do spring and autumn infest with diseases? Is it because all heavy mutations occur? But autumn is heavier than spring, because we are more likely to fall ill when a warm body is cooling than when a cold one is heating up. Just as, therefore, cold in spring warms up, so in autumn heat cools down.