On Medicine (De Re Medica)

as Asclepiades contends. He holds that a physician will only treat correctly if the original source of the disease has not escaped his notice. Nor do they deny that experiments are also necessary; but they contend that even these could not have been approached without some reasoning. For they argue that the ancients did not force just anything upon the sick, but rather pondered what was most appropriate, and tested through practice what a previous conjecture had suggested. They argue that it does not matter if many things were tested at the beginning, as long as they started with a plan. This is indeed the case in many matters. They note that new types of diseases often occur, in which experience has yet to show anything, so that it becomes necessary to observe where they began; for without this, no mortal could discover why he should use this treatment rather than that. And for these reasons, they pursue causes that are hidden.

They call those causes evident in which they investigate whether heat, or satiety, or similar things have brought on the beginning of a disease; for they believe that he who is not ignorant of the origin will arrive at a remedy more quickly.

They call the natural actions of the body those through which we draw in and release breath, take in and digest food and drink, and also those through which these same things are distributed into all parts of the limbs. Then they also inquire why our veins sometimes subside and sometimes lift, and what the reason is for sleep and for waking. They think that without knowledge of these, no one can either approach or heal diseases arising among them. And because digestion seems to pertain to the matter as much as possible, they focus primarily on this; and, led by others,