And Galen's Commentary on it, Book 1. 7

Charterius Edition Vol. IX [3.] Basel Edition Vol. V (345.)

...from the imbalance of the surrounding air original Greek: "δυσκρασίας τοῦ περιέχοντος" (dyskrasias tou periechontos). This refers to a "bad mixture" of the atmospheric conditions like heat and moisture.. For in this way, even if all other conditions are omitted, we will be able to discover their powers ourselves.

Therefore, whoever wishes to benefit greatly in the medical art from reading the Epidemics should first read these works:
1. On the Nature of Man
2. On Airs, Waters, and Places
3. Those Aphorisms where the author discusses the seasons and teaches the powers of cold, hot, dry, and moist conditions.

In addition to these, it is necessary to have studied the Prognostic. The observations written in the Epidemics follow from the principles taught in those books.

First, health is a certain symmetry symmetria: a balanced proportion or "due measure" of qualities of the primary elements, which are the hot, cold, dry, and moist.

Second, Spring is the most temperate season when it maintains its proper mixture original Greek: "κρᾶσιν" (krasin); Latin: "temperaturam." This is the foundational Greek medical concept of "crasis," where the four qualities are blended perfectly.. Because of this balance, blood increases during the Spring. In the same way, Summer is hotter and drier than what is appropriate, while Winter is moister and colder. Finally, Autumn is unequal in its temperament, during which the quality of dryness...