This is what the whole course of history teaches us. Every race has its own modes of thinking; every race, capable of developing a civilization, develops one peculiar to itself, and which it cannot engraft upon any other, except by amalgamation of blood, and then in but a modified degree. The European cannot win the Asiatic to his modes of thinking; he cannot civilize the Australian, or the Negro; he can transmit but a portion of his intelligence to his half-breed offspring of the inferior race; the progeny of that half-breed and the nobler branch of his ancestry, is but one degree nearer, but not equal to that branch in capacity: the proportions of blood are strictly preserved. I have adduced illustrations of this truth from the history of various branches of the human family, of the lowest as well as of the higher in the scale of intellectual progress. Are we not, then, authorized to conclude that the diversity observable among them is constitutional, innate, and not the result of accident or circumstances--that there is an absolute inequality in their intellectual endowments? FOOTNOTES: [181] The word _Arab_ is here used instead of the more common, but less correct, term _Saracen_, which was the general appellation bestowed on the first propagators of the Islam by the Greeks and Latins. The Arab civilization reached its culminating point about the reign of Harun al Rashid. At that time, it comprised nearly all that remained of the arts and sciences of former ages. The splendor and magnificence for which it was distinguished, is even yet the theme of romancers and poets; and may be discerned to this day in the voluptuous and gorgeous modes of life among the higher classes in those countries where it still survives, as well as in the remains of Arab architecture in Spain, the best preserved and most beautiful of which is the well-known Alhambra. Though the Arab civilization had a decidedly sensual tendency and character, it was not without great benefits to mankind. From it our forefathers learned some valuable secrets of agriculture, and the first lessons in horticulture. The peach, the pear, the apricot, the finer varieties of apples and plums, and nearly all of our most valued fruits were brought into Western and Central Europe by the returning crusaders from the land of the Saracens. Many valuable processes of manufacture, and especially of the art of working metals, are derived from the same source. In the science of medicine, the Arabs laid the foundation of that noble structure we now admire. Though they were prevented by religious scruples from dissecting the human body, and, therefore, remained in ignorance of the most important facts of anatomy, they brought to light innumerable secrets of the healing powers in the vegetable kingdom; they first practised the art of distillation and of chemical analysis. They were the beginners of the science of Chemistry, to which they gave its