_The Effects of the Arab Renaissance as a Whole upon the Evolution of Medicine._--Although the series of events which I have endeavored to sketch here in brief outlines reveals an extraordinary degree of zeal and persistence on the part of the Arab rulers and their subjects to endow the nation with the knowledge and skill of their models, the Greeks, the final results gained, at least so far as they relate to the evolution of medicine as a whole, were not very great. The movement lasted for five or six centuries, but nevertheless only a few relatively unimportant facts were added by the Arabs to the stock of knowledge which was possessed at the time of Galen’s death. Alhazen’s brilliant researches in the eleventh century of our era in optics (more particularly with reference to refraction) paved the way for a more perfect knowledge, in modern times, of the physiology of vision; Geber, who lived during the eighth century of the Christian era, and who is spoken of by Le Clerc as “occupying the same place in the history of chemistry that Hippocrates does in the history of medicine,” laid the foundations of that important branch of science; Abulcasis discovered the Medina worm (_dracunculus Medinensis_) and wrote an excellent description of the pathological effects which it produces when it lodges under the skin of a man’s leg; and, finally, our pharmacopoeia was enriched, during these centuries, by the addition to it of a number of new drugs and pharmaceutical preparations. These are among the more important contributions which the Arabs made to the general stock of medical knowledge. On the other hand, they contributed, in an indirect manner, to the advance of the science of medicine. From the thirteenth century onward, for a long period, the Latin language was destined to serve as the vehicle by means of which all scientific knowledge was to be spread abroad in the countries which are now known as Italy, Spain, France, Switzerland, Germany, Belgium and Holland, and therefore an immense amount of translating had to be done before the works of Hippocrates, Galen and other Greek medical authors could be brought within reach of the physicians of these different countries. At that late date it was by no means always feasible to get possession of an original copy of one of these classical treatises, and consequently in such cases it became necessary to employ an Arabic version in the place of the Greek original. It was in this indirect manner, therefore, that the Mohammedan Renaissance contributed most effectively in advancing the development of medical science in general.