Disputatio medica, de cibo et potu

causes, which we have said are necessarily efficient, altering, and changing our body.

IIX.

The human body is thus established and formed by natural things, and it is conserved not only through the expulsion of excrements, which have been collected through digestion, but also (because the body is in a continuous state of flow) through the restoration of that which has flowed away.

IX.

Who doubts that something is always flowing out from the human body? For if nothing flowed out from our bodies, but an equal mass of substance were always preserved, there would be no need for nourishment.

X.

Since it is true, therefore, that the entire mass of living creatures is in a perpetual state of flow, if a similar substance is not restored for that which has flowed away, it will certainly evaporate, and the whole will be dissipated.

XI.

Lest this happen prematurely, it is necessary for us to eat and drink.

XII.

This non-natural thing (of which we speak here) is so constituted that it always alters, changes, and moves the human body.

XIII.

It alters and moves in two ways: sometimes according to nature, sometimes contrary to nature.