Galen's Commentaries on the Aphorisms of Hippocrates

[...] is related proportionally, about which Hippocrates himself often spoke, although he did not say so here, as one who left other things for us to recall to memory from this one. For whatever things the summer season [indicates], the same will also be indicated together by the temperament of the sick person, if it be hotter and drier; and by his age, if he be in his prime; and by the place, if it be hot and dry. It is clear, moreover, that the mode of life and habit are related in the same way, as well as the present constitution of the ambient air, concerning which he will teach later. So also, whatever things were assumed concerning the autumnal season for the constitution of the disease and the recurrence of the paroxysms: these same things may be assumed concerning the age and nature of the patient, the mode of life and habit, the region in which he is sick, and the temperature of the ambient air (which then prevails). From these things it can now be established that we shall know both the constitution of the disease and its paroxysms. The constitution, indeed—whether the disease be very acute or long-lasting—is necessary for foreknowing the time of its status. But the paroxysms [reveal] whether they will attack on the third day, or the fourth, or every day, or at what hour of the day or night.

What he writes near the end of the Aphorism, let us next see, whether they serve to clarify those things we have said; for Hippocrates says: "And the successive increases of the circuits, whether they occur daily, or on alternate days, or at greater intervals." It is clear, however, that by "increases of the circuits" he understands the augmentations of the paroxysms which happen in them; from which I have shown that both the augmentation of the disease and the predetermined time of its future vigor may be learned from this. The increase of the second paroxysm relative to the first consists in these three things: in the hour at which the paroxysm occurs, in the duration of the paroxysm, and in its magnitude. [illegible — ink blot]? however, it makes no difference if you also say "intensity," because these two terms are used by physicians, and quite often the same things are pronounced regarding that matter, when they sometimes say the fever was greater than the one preceding it, and sometimes more intense. It happens, moreover, that this intense fever may last for the same number of hours as the preceding one, or fewer, or more; which pertains not to the magnitude or intensity of the paroxysm, but to its duration.

By "paroxysm," moreover, you ought to understand the worse period of the whole circuit: which is from the first onset until the time of its status, just as the remaining time of the decline is better. Therefore, when a paroxysm—whether it occurs on the third day, the fourth, or daily—has anticipated [the time] by a similar proportion, and by so anticipating is extended to a longer time, and furthermore afflicts more intensely, then the augmentation of the disease is manifest; and how much it is augmented will be shown by each of the aforementioned factors in its own quantity. If indeed the paroxysm, anticipating by more time, and lasting longer, and also afflicting much more intensely, it will indicate an augmentation worthy of mention, and that the motion of the disease is swift, and that it will be in its vigor not long thereafter. For it cannot happen that, when the paroxysms receive great increases, the status of the disease is not very near. But the contrary paroxysm, namely one which makes small increases in all those things we have mentioned, shows that the future vigor of the disease is farther away, as far as this is concerned.

Therefore, we shall learn this very thing through the increases of the circuits: namely, to attain by conjecture after how much time the disease will stand in its vigor, and besides, the predetermined hour at which the paroxysm will attack. The first knowledge is conducive to establishing the form of the entire regimen. The second, however, to the knowledge of the particular times in which food is to be given, the purposes of which he himself proposed to teach from the beginning. Moreover, I think no one doubts that he calls the return of the same thing a "circuit." But he also says that from those things which soon appear, we must conjecture concerning the paroxysm and the constitution of the entire disease. Whether one wishes [to call them] accidents or signs...