And whilst it was thus simple to suppose that there were several _faci_ of the creation of man, as well as of other beings; and whilst this doctrine, so conformable to all the data furnished by natural science, removed all geographical objections, explaining thus all the analogies and differences of human types, and the repartition of each group; whilst, in one word, it exactly accounted for all the known facts, the opposite doctrine moved in a circle of contradictory suppositions superimposed by hypotheses; theories founded upon a small number of facts upset by other unexpected facts; imaginary influences refuted by observation; anti-historical legends dispelled by historical monuments; lame explanations destroyed by physiology; obscure sophisms refuted by logic; and all this to demonstrate, not exactly that all races descend from the same pair, but that, strictly speaking, such is not altogether impossible. Whence have the monogenists derived the requisite perseverance and courage to impose upon their reason such continuous restraint, and to resist the testimonies of observation, science, and history? On analysing their system, we find at every moment two fundamental axioms which serve them as articles of faith, and the evidence of which appears to them sufficient to surmount all other objections. These two axioms have served as the premises of an apparently irresistible syllogism. 1. All animals, capable of producing an eugenesic progeny, are of the same species. 2. All human crossings are eugenesic. Therefore, all men are of the same species. The monogenists, convinced of the reality of the premises of this syllogism, thought their doctrine to stand on a solid foundation, and defended it with that confidence inspired by conviction. Assailed by pressing objections, constantly obliged to yield, incapable of advancing a step without an immediate retreat, they felt their forces revive by resorting to their syllogism, like Antæus when he touched the earth. As long as the refuge remained they continued the struggle, though not with advantage, at least with the ardour of faith; for though faith no longer moves mountains, it still leaves the hope of moving them.