WHEN speaking in a former work of the distinct races of mankind, I remarked that, ‘if all the leading varieties of the human family sprang originally from a single pair,’ (a doctrine, to which then, as now, I could see no valid objection,) ‘a much greater lapse of time was required for the slow and gradual formation of such races as the Caucasian, Mongolian, and Negro, than was embraced in any of the popular systems of chronology.’

In confirmation of the high antiquity of two of these, I referred to pictures on the walls of ancient temples in Egypt, in which, a thousand years or more before the Christian era, ‘the Negro and Caucasian physiognomies were portrayed as faithfully, and in as strong contrast, as if the likenesses of these races had been taken yesterday.’ In relation to the same subject, I dwelt on the slight modification which the Negro has undergone, after having been transported from the tropics, and settled for more than two centuries in the temperate climate of Virginia. I therefore concluded that, ‘if the various races were all descended from a single pair, we must allow for a vast series of antecedent ages, in the course of which the long-continued influence of external circumstances gave rise to peculiarities increased in many successive generations, and at length fixed by hereditary transmission.’