This part of a series of posts, with the same rider: this is published here because of our interest in ancient greek medical theory.  We do not necessarily endorse the ideas. The “Unani” part of Unani Tibb Medicine, that is, the elements from Greek medicine that the Islamic doctors adopted as part of Islamic medicine, does give some background to the theories that held sway with, for example, Ibn Sina.

Greek Medicine from Hippocrates to Galen: Studies in Ancient Medicine Edited by John Scarborough Philip J. van der Eijk Ann Ellis Hanson Joseph Ziegler write, 

“However, this variation of humours according to the hours is also attested in Vindician’s Letter to his young child Pentadius, which is a Latin translation of a Greek text similar to those collected here and which claims to go back to Hippocrates.”

“This letter presents both the theory of the four humours, varying according to the seasons and ages, and the theory of the four temperaments, but it adds that the humours vary also according to the hours of the day and night. I give here the extracts relevant to the comparison of the predominance of the humours according to the hour, and also the theory of the four temperaments.” 

“The body of man is composed of four humours. For he has in him blood, yellow bile, black bile and phlegm … 

“These four humours are divided amongst each other day and night. Blood dominates for six hours, i.e. after the ninth hour of the night until the third hour of the day; then yellow bile dominates after the third hour until the ninth hour. Black bile dominates after the ninth hour of the day until the third hour of the night. Phlegm dominates after the third hour of the night until the ninth hour of the night …”

“Moreover, these four humours give men the following characters:

  1. Blood makes men well-intentioned, direct, moderate, attractive, of good humour (or full of moisture).

  2. Yellow bile makes men quick-tempered, intelligent, shrewd, light-spirited, thin, they eat a lot and digest quickly.

  3. Black bile makes men deceitful, angry, miserly, fearful, sombre, sleepy, jealous, and frequently having black scars on their feet.

  4. Phlegm gives men well-formed bodies, stimulated, reflective, quickly growing white hairs on their head, much less bold.”