_Averroes._--Averroes was one of Avenzoar’s most distinguished pupils. Indeed, the latter’s famous work, the Teïssir, is dedicated to Averroes. Thanks to the distinguished French historian and philosopher, Ernest Renan, our knowledge of Averroes has been greatly expanded since 1852. Averroes was born at Cordova in 1126 A. D. His father and his grandfather had both held the office of Cadhi (Alcalde, in Spanish), and were therefore people of importance in that city. His studies were confined at first largely to philosophy, and when he reached mature age he gained a great reputation as the commentator and interpreter of the writings of Aristotle. Still later in life much of his attention was devoted to medicine, and he wrote a book which bears the title “Kitab al-kullidschat” (General principles of Medicine). Among the physicians of the later Middle Ages this work was commonly spoken of as the “Colliget” (from kullidschat), and was almost as highly esteemed as the Canon of Avicenna. The idea of writing a treatise on the individual diseases was first entertained, among Arabian physicians, by Averroes; but on reflection he abandoned the idea, and, instead, urged Avenzoar, his friend and former instructor, to undertake the work in his place. It was in this way that the Teïssir--the finest work on the practice of medicine produced by an Arab writer--came to be written. The topics treated in the “Colliget” are distributed throughout the seven books in the following manner:-- Book I. Anatomy. Book II. Health (Physiology). Book III. Diseases. Book IV. Signs or Symptoms. Book V. Remedial agents and Foods. Book VI. The Preservation of Health. Book VII. The Treatment of Diseases. Neuburger speaks of the “Colliget” as a fine piece of philosophical writing, but adds that it is not at all suited to the needs of the practical physician. Indeed, he doubts whether any person who has not received a thorough training in natural philosophy--the philosophy of Aristotle--would be able to follow the author intelligently.