Harriet Ritvo, The Platypus and the Mermaid, and other Figments of the Classifying Imagination (Harvard University Press, 1997) - Robert Knox

[T]he Dutch families who settled in Southern Africa three hundred years ago, are now as fair, and as pure in Saxon blood, as the native Hollander; the slightest change in structure or colour can at once he traced to intermarriage. By intermarriage an individual is produced, intermediate generally, and partaking of each parent; but this mulatto man or woman is a monstrosity of nature — there is no place for such a family: no such race exists on the earth, however closely affiliated the parents may be. To maintain it would require a systematic course of intermarriage, with constant draughts from the pure races whence the mixed race derives its origin. Now, such an arrangement is impossible. Since the earliest recorded times, such mixtures have been attempted and always failed; with Celt and Saxon it is the same as with Hottentot and Saxon, Caffre and Hottentot. The Slavonian race or races have been deeply intercalated for more than twice ten centuries with the South German, the pure Scandinavian, the Sarmatian, and even somewhat with the Celt, and with the Italian as conquerors: have they intermingled? Do you know of any mixed race the result of such admixture? Is it in Bohemia? or Saxony? or Prussia? or Finland?

But the land of Egypt still abounds with its ancient monuments; the race was quite peculiar, and was, I think, African, or at least allied to the African races. The mouth and lips all but prove this. Nevertheless, their identity with a great section of the present Jewish race cannot be doubted; the young Jew of London or Amsterdam might readily sit for a likeness of the bust of Amenoph.

The source of all evil lies in the race, the Celtic race of Ireland. There is no getting over historical facts. Look at Wales, look at Caledonia; it is ever the same. [...] The race must be forced from the soil; by fair means, if possible; still they must leave. The Orange club of Ireland is a Saxon confederation for the clearing the land of all Papists and Jacobites; this means Celts. If left to themselves, they would clear them out, as Cromwell proposed, by the sword; it would not require six weeks to accomplish the work. But the Encumbered Estates Relief Bill will do it better.