The name of medicine is thought to have been given from 'moderation', modus, that is, from a due proportion, which advises that things be done not to excess, but 'little by little', paulatim. For nature is pained by surfeit but rejoices in moderation. Whence also those who take drugs and antidotes constantly, or to the point of saturation, are sorely vexed, for every immoderation brings not health but danger.

Isidore of Seville: the medical writings (ed. 1964)