At the end of the eleventh century the Crusaders, under the leadership of Godfrey de Bouillon and others, made their first serious attack on Palestine and Syria, and from that time onward, for about two centuries, they and the different armies sent out successively from Europe carried on almost constant warfare, which Michaud the distinguished French historian (about 1800 A. D.) calls the product of a pious delirium. Wars of religion are the most savage and pitiless of all wars, says Le Clerc, and this was emphatically true of those waged by the Crusaders. On the other hand, says the same writer, “the tolerance exhibited at that period by the Arabs in religious matters is a well-attested fact, and it owes its origin to the circumstance that their scientific education was conducted by Christians. Of Saladin’s fifteen physicians two-thirds were either Jews or Christians. Cultivation and good training were the characteristics of the Arabs at that period of their history, whereas fanaticism and brute force were the distinguishing features of the European soldiers. Several hundred thousand adventurers first ravaged Europe and then pounced upon Asia. At Antioch Godfrey de Bouillon committed all sorts of excesses, and then, when he had taken Jerusalem, he massacred 70,000 of its inhabitants--Jews and Musulmans. Eighty years later, Saladin retook Jerusalem; and, with the exception of a comparatively small number, he allowed all of his captives to go free. His brother, Malek el Adel, paid the ransom of 2000 of the prisoners. Contrast these fruits of civilization with the barbarism of the European conquerors under Godfrey de Bouillon. Another result of the Crusades was this: The Franks lost a good deal of their savagery through contact with the Arabs. At a still later period Western Europe drew a large part of her supplies of knowledge from Spain--_i.e._, from the Musulmans.” _Syria._--In the thirteenth century Damascus, the capital of Syria, assumed considerable importance as a centre of medical activity. Bagdad and Cairo had by this time lost the greater part of their attractiveness for those who wished to perfect their knowledge of the healing art, and the vandalism of the so-called Soldiers of the Cross had put an end for many years to come to all hopes of making Constantinople once more the home of scientific or artistic effort. There was one branch of medical practice, however, in which the Cairo physicians excelled all others--that, namely, of ophthalmology. This is explained by the well-known fact that at all periods of her history Egypt has been afflicted with ophthalmias to a much greater degree than any of the other countries of the Mediterranean basin. The great wealth accumulated in Damascus, the large number of hospitals which were located in the city, and the attractiveness of the town as a place of residence undoubtedly had much to do with the fact that it attained at this period so great popularity as a centre of medical activity.