Leclerc gives the names of more than one hundred known translators who not only dealt with the physicians but with the Greek philosophers, mathematicians and astronomers. The writings of the physicians of India and of Persia were also translated into Arabic. But close upon the crowd of translators who introduced the learning of Greece to the Arabians came original observers of the first rank, to a few only of whom time will allow me to refer. Rhazes, so called from the name of the town (Rai) in which he was born, was educated at the great hospital at Bagdad in the second half of the ninth century. With a true Hippocratic spirit he made many careful observations on disease, and to him we owe the first accurate account of smallpox, which he differentiated from measles. This work was translated for the old Sydenham Society by W.A. Greenhill (1848), and the description given of the disease is well worth reading. He was a man of strong powers of observation, good sense and excellent judgment. His works were very popular, particularly the gigantic "Continens," one of the bulkiest of incunabula. The Brescia edition, 1486, a magnificent volume, extends over 588 pages and it must weigh more than seventeen pounds. It is an encyclopaedia filled with extracts from the Greek and other writers, interspersed with memoranda of his own experiences. His "Almansor" was a very popular text-book, and one of the first to be printed. Book IX of "Almansor" (the name of the prince to whom it was addressed) with the title "De aegritudinibus a capite usque ad pedes," was a very favorite mediaeval text-book. On account of his zeal for study Rhazes was known as the "Experimentator."