Galen's Commentaries on the Aphorisms of Hippocrates

... indeed conjecturally, yet not unmethodically, nor far from the truth, but closely and very nearly shall we arrive at foreknowing the future time of the [disease's] standing, and the successive recurrences of the paroxysms. But Hippocrates taught all these things more extensively, both in the books entitled Prognostics and in the others entitled Epidemics; and we, according to the opinion of the ancient master, have set down his words with a fitting exposition in the first book On Crises, in which we showed how anyone might foreknow the future vigor of a disease. Now, however, all things are delivered by Hippocrates in summary chapters. But we shall elucidate them as briefly as possible. Let those whose concern it is to learn the whole discipline of these matters diligently proceed to read the book On Crises written by us. Therefore, the diseases themselves, and the ratios of the paroxysms, and likewise their own constitutions, will nonetheless show [the timing]; as indeed in intermittent [fevers], that the tertian is quickly terminated, while the quotidian is long, and the quartan exists as longer even than this. But in continuous [fevers]: those that are burning are acute, while those named typhodes (that is, smoldering or quotidians) are longer, and the semitertians are intermediate between these. Since? however someone might distinguish all these fevers immediately as they attack, in the second book On Crises [illegible — ink stain]? im?? Wherefore it is not? necessary to transfer the discourse hither to whatever things we have already? anticipated saying well, nor are the same things to be repeated too often in many books; but only to recall to memory, if it were possible to know a tertian attacking immediately from the beginning, that we can understand from it that it will terminate quickly, and that paroxysms will occur every third day; and this is what is said by Hippocrates: "The paroxysms and constitutions will indicate the disease."

Indeed, since we have often recognized the beginnings of quartan fevers immediately on the first day, without waiting for the second paroxysm, we established the form of diet from the start as if for a disease that would arrive at its vigor after a long time; so we did in the quotidian and the tertian, measuring the time of future vigor in both according to their proper limit. Moreover, as in fevers, the same must be done in other diseases. For the lateral disease, and those named peripneumonia and phrenitis by the Greeks, are acute diseases. But angina, juxtangina, cholera, and tension of the nerves are peracute; dropsy, black bile, suppuration, and wasting are chronic. And in the lateral disease and phrenitis, paroxysms occur for the most part every third day; but in suppurations that occur in the belly or the liver, and in wasting, they occur daily, and more toward night; but those who suffer from the spleen and generally from black bile, [have them] every fourth day. Furthermore, what is said immediately following regarding the seasons of the year has a relation to those things said before; for both the constitutions of diseases and the paroxysms can be indicated by the seasons of the year along with the disease. For it is not enough to have known only this, that a quartan has attacked on this day, so that we may foreknow from the beginning that the regimen of diet must be established as for a future chronic disease; but we must also look forward to whether it has made its beginning in winter, spring, summer, or autumn, knowing this: that in summer, quartans are for the most part short, autumnal ones long, and those more so which touch upon winter. For he himself will teach us these same things in what follows. And indeed, although a tertian fever otherwise terminates quickly, it terminates even more quickly in summer than in winter; and likewise for each of the other diseases, summer adds speed, but winter slowness. But also the paroxysms: for the most part they occur every third day in summer, every fourth day in autumn, and every day or night in winter. Moreover, just as in the seasons of the year, so also in the temperaments from...