De morborum temporibus, Principum Medicorum Aphorismoi

XXI.
Finally, types are either simple or composite: the former consist of a single invasion and remission; the latter consist of many.
1. Simple types are the quotidian, tertian, quartan, quintan, sextan, etc., up to the fifteenth-day fever.
2. The quotidian, I say, is not just any fever invading daily (as the ancient Latins understood it; for which reason they even counted two tertians and three quartans), but what the Greeks and Pliny properly called ἀμφήμερον every-other-day or ἀμφημέρινον quotidian.
3. The matter for two tertians and a double tertian proceeds from a dual focus: for the former, on different days; for the latter, on the same day.
4. Galen denies that a quintan, etc., exists, following Hippocrates: yet the authority of Avicenna and the experience of Rhazes oppose Galen.
5. Under the simple types are also the types of confused fevers, both in continuous remitting fevers and in intermittent ones.
6. There are those, however, who teach that confused fevers are only ever intermittent, while others teach that continuous fevers can also be confused. Fernel, book 4, chap. 2, 15.

XXII.
The more strongly one possesses the causes of the humors, such as quantity, quality, and corruption, the more quickly one is moved.
1. Phlegm is regenerated more quickly in such quantity that it can be the cause of an accession, as it is made from the cold, moist, and viscous portion of food, when the heat of the stomach is too remiss to dissolve it much.
2. Porraceous bile is generated from warmer foods by the more intense heat of the stomach, so that by reason of both it is dissolved much, and a sufficient quantity is not regenerated so quickly.
3. Similarly, neither is the bile generated from the thinner part of the chyle by the more intense heat of the liver.
4. Since melancholy is made from the thick portion of the chyle, which is very scarce (for the abundant portion degenerates into feces), through the more intense heat of the liver, a sufficient quantity is regenerated over a long time. If this is less and thicker, it becomes a quintan, sextan, etc.
5. By reason of its qualities, melancholy also moves very slowly.
6. Although bile is more fluid than phlegm due to heat and thinness, it moves more quickly than the latter because it is regenerated more quickly.
7. Finally, the corruption of phlegm is more abundant than that of bilious or melancholic humor.
8. Therefore, the causes of the types are not the planets, nor the mere quantity of humors, nor a specific property, nor the property of putrefaction. Astrologers, Conciliator, Alexander, Trallianus, Gentilis, Fernel.

XXIII.
Composite types are either from homogeneous or heterogeneous humors.