Galen's Commentaries on the Aphorisms of Hippocrates

...how much truth they have, [the physician] must not only present himself doing the right things at the right time, and omitting nothing that could benefit the sick person, but the sick person himself must obey the physician and in no way indulge his own pleasure; suitable attendants must also be present, and all external things must be prepared. For because of these things, it often happens that either prognosis, or treatment, or both, are interrupted. External things, moreover, are suitable dwellings, whether full of crowds or void of all disturbance, and furthermore those things which are announced or done that inflict anger, sadness, or any other emotion upon the sick person. Just as those things which sometimes break the night's sleep, which can happen in a thousand ways. If therefore, he says, all these things are well and rightly disposed, none of the things written in this book will be found to be false.

Ornamental initial I with floral/foliate motifsIN disturbances of the belly and spontaneous vomitings, if such things are purged as ought to be purged, it is beneficial and they bear it easily; but if otherwise, the opposite. So also the emptying of the vessels, if it occurs in such a way as it ought to occur, is beneficial and they tolerate it well; but if otherwise, the opposite. One must therefore look to the region, and the season, and the age, and the diseases, in which it may be appropriate or not.

Ornamental initial N with foliate motifsHis discourse is not about the quantity of those things that are evacuated, as some have thought, but only about the quality, as the two words "of what kind" [qualia] and "of what sort" [qualis] manifest. For in those evacuations that happen spontaneously, he said before: "If such things as ought to be purged are purged, it is beneficial and they bear it easily." But in others which are performed by the physician: "If it occurs in such a way as it ought to." And yet he could have said: "if as much as ought to be purged is purged," and again, "if it becomes as great as it ought to be." He shows the same thing also from the word "to be purged" [purgari]; for he did not simply say "if such things as ought to be evacuated," but "if such things as ought to be purged." For purgation is the evacuation of humors that cause trouble by their quality. In these matters, therefore, many commentators err, who perceive neither the words nor the mind of the man correctly. But they sin even more when some take "emptying of the vessels" to mean fasting, and others venesection; for Hippocrates is accustomed to call evacuation "emptying of the vessels" from its result, because in all evacuations it happens that the vessels are emptied. His discourse now is indeed concerning the quality of those things that are evacuated. But just as he always exhorts that the physician should imitate in the works of his art those things which are rightly done by nature, so also now he has done the same, beginning his discourse from spontaneous evacuations, in which if such things as ought to be purged are purged (that is, those things which infest the body), it is beneficial and they bear it easily. But if the evacuation of other things happens, and not of those which trouble our bodies, the opposite occurs; for it is not beneficial, and the sick bear it heavily. In like manner, if the physician endeavors to effect some evacuation, let it be of those things which trouble our bodies, just as in other places he prescribes the noxious humor to be evacuated, nor should another be preferred to it in evacuation. If, therefore, phlegm should abound, this must by all means be evacuated; but if yellow or black bile is troublesome, one must abstain from phlegm, and the troublesome bile must be evacuated. So also if the sanguine humor has exceeded its measure in the body, the blood ought to be evacuated, as also its serous part, if this should be superabundant. We ought to conjecture the superabundant humor from the color, unless by chance some have receded into the depths. For a similar color blooms from the humors, if they have not been swallowed up. In those especially, therefore, which have receded and are not diffused through the whole body in equal portion, one must look to the region, and the season of the year, and the age, and the diseases, in which it may be appropriate or not—that is, in which the evacuation of such or such a humor may be appropriate or not.