fostered in the _Sefer Asaf_, a curious medical fragment of uncertain authorship and origin, by its rehearsal of an old Midrash, which traces the origin of medicine to Shem, son of Noah, who received it from angels, and transmitted it to the ancient Chaldeans, they in turn passing it on to the Egyptians, Greeks, and Arabs. Though the birth of medicine is not likely to have taken place among Jews, it is indisputable that physicians of the Jewish race are largely to be credited with the development of medical science at every period. At the time we speak of, Jews in Egypt, northern Africa, Italy, Spain, France, and Germany were physicians in ordinary to caliphs, emperors, and popes, and everywhere they are represented among medical writers. The position occupied in the Arabian world by Israeli, in the Occident was occupied by Sabattaï Donnolo, one of the Salerno school in its early obscure days, the author of a work on _Materia medica_, possibly the oldest original production on medicine in the Hebrew language. The period of Jewish prosperity in Spain has been called a fairy vision of history. The culture developed under its genial influences pervaded the middle ages, and projected suggestions even into our modern era. One of the most renowned _savants_ at the beginning of the period was the statesman Chasdaï ben Shaprut, whose translation of Dioscorides's "Plant Lore" served as the botanical textbook of mediæval Europe. The first poet was Solomon ibn Gabirol, the author of "The Source of Life," a systematic exposition of Neoplatonic philosophy, a book of most curious fortunes. Through the Latin translation, made with the help of an apostate Jew, and bearing the author's name in the mutilated form of Avencebrol, later changed into Avicebron, scholasticism became saturated with its philosophic ideas. The pious fathers of Christian philosophy, Albertus Magnus and Thomas Aquinas, took pains to refute them, while Duns Scotus and Giordano Bruno frequently consulted the work as an authority. In the struggle between the Scotists and the Thomists it had a prominent place as late as the fourteenth century, the contestants taking it to be the work of some great Christian philosopher standing on the threshold of the Occident and at the portals of philosophy. So it happened that the author came down through the centuries, recognized by none, forgotten by his own, until, in our time, behind the Moorish-Christian mask of Avencebrol, Solomon Munk discovered the Jewish thinker and poet Solomon ibn Gabirol. The work _De Causis_, attributed to David, a forgotten Jewish philosopher, must be classed with Gabirol's "Source of Life," on account of its Neoplatonism and its paramount influence upon scholasticism. In fact, only by means of a searching analysis of these two works can insight be gained into the development and aberrations of the dogmatic system of mediæval philosophy.