Evolution quotes

For although there seems to be so great a difference between widely separate nations, that you might easily take the inhabitants of the Cape of Good Hope, the Greenlanders, and the Circassians for so many different species of man, yet when the matter is thoroughly considered, you see that all do so run into one another, and that one variety of mankind does so sensibly pass into the other, that you cannot mark out the limits between them. [Johann Blumenbach, On The Natural Variety of Mankind, in Anthropological Treatises, 1865 English edition, first published in 1775, p98]