Toward the close of their career, the Arabian doctors began the practice of dissecting and the closer study of anatomy and physiology, which added much to the power of the science. Yet they still believed in the "elixir of life," and tried to work miracle cures, which in many respects may have been successful. It is a question whether they went any farther into the practice of miracle cures than the quacks and charlatans and faith doctors of modern times have gone. The influence of their study of medicine was seen in the great universities, and especially in the foundation of the University at Salerno at a later time, which was largely under the Arabian influence. _Metaphysics and Exact Science_.--It would seem that the Arab-Moors were well calculated to develop psychological science. Their minds seemed to be in a special measure metaphysical. They laid the foundation of their metaphysical speculations on the philosophy of the Greeks, particularly that of Aristotle, but later they attempted to develop originality, although they succeeded in doing little more, as a rule, than borrowing from others. In the early period of Arabian development the Koran stood in the way of any advancement in philosophy. It was only at intervals that philosophy could gain any advancement. Indeed, the philosophers were driven away from their homes, but they carried with them many followers into a larger field. The long list of philosophers who, after the manner of the Greeks, each attempted to develop his own separate system, might be mentioned, showing the zeal with which they carried on inquiry into metaphysical science. As may be supposed, they added little to the sum of human knowledge, but developed a degree of culture by their philosophical speculations. But it is in the exact sciences that the Arabs seem to have met with the greatest success. The Arabic numerals, probably brought from India to Bagdad, led to a new and larger use of arithmetic. The decimal system and the art of figures were {311} introduced into Spain in the ninth century, and gave great advancement in learning. But, strange to relate, these numerals, though used so early by the Arabs in Spain, were not common in Germany until the fifteenth century. The importance of their use cannot be overestimated, for by means of them the Arabians easily led the world in astronomy, mechanics, and mathematics. The science of algebra is generally attributed to the Arabians. Its name is derived from gabara, to bind parts together, and yet the origin of this science is not certain. It is thought that the Arabs derived their knowledge from the Greeks, but in all probability algebra had its first origin among the philosophers of India.