Isa bin Musa, who flourished about A.D. 833, was also one of the most distinguished physicians of the period. He left the following works:
(1) Book on the forces of alimentary substances.
(2) A treatise for a person who has no access to a physician.
(3) Questions concerning derivations and races.
(4) Book of dreams, indicating why medicines should not be given to pregnant women.
(5) Book of the remedies mentioned by Hippocrates in his treatise on bleeding and cupping.
(6) Dissertation on the use of baths.
Without giving any details about Maseweih, Yahya bin Maseweih, Honein bin Ishak, and Kosta bin Luka, all of whom were distinguished for medical knowledge, some fuller mention must be made of Abu Bakr Ar-Razi (Rhases), who has been described as 'the ablest physician of that age and the most distinguished; a perfect master of the art of medicine, skilled in its practice, and thoroughly grounded in its principles and rules.' He composed a number of useful works on medicine, and some of his sayings have been handed down to us, and are still worthy of record, such as:
(1) When you can cure by a regimen, avoid having recourse to medicine.
(2) When you can effect a cure with a simple
medicine, avoid employing a compound one.