of his translation of Galen is preserved in the British Mus. MSS. Addit. 14661 and 17156: in the latter are fragments of the "Medical art" and "Faculties of the aliments" which have been edited by Sachau (Inedita Syriaca, Vienna, 1870). Of his philosophical work Sachau has given us the versions which he made of the Isagoge and Table of Porphyry, and Aristotle's Categories and the dubious de mundo, as well as a treatise on "the soul" which is not the de anima of Aristotle. He wrote original treatises on logic in seven books (incomplete—Brit. Mus. Add. 14660 contains that on the categories), on "negation and affirmation," on "genus, species, and individual," on "the causes of the universe according to Aristotle" and minor essays. In astronomy he has left a tract "on the influence of the moon" which is based on the work of Galen (cf. Sachau, op. cit.) The writings of Sergius circulated amongst both Nestorians and Monophysites, all regarding him as a leading authority on medicine and logic, and in medicine it seems that he was the founder of a Syriac school which became the parent of Arabic medicine, certainly that school owed its impetus to him. Bar Hebraeus refers to him as "a man eloquent and greatly skilled in the books of the Greeks and Syrians and a most learned physician of men's bodies. He was indeed orthodox in his opinions, as the "Prologue" bears witness, but in morals corrupt, depraved, and stained with lust and avarice" (Bar Hebraeus. ed. Abbeloos et Lamy. i. 205-7).
