Voltaire (1694-1778) was a French Enlightenment writer, historian and philosopher. He was a polygenist: one who believed that each race had separate origins:
It is a serious question among them whether the Africans are descended from monkeys or whether the monkeys come from them. Our wise men have said that man was created in the image of God. Now here is a lovely image of the Divine Maker: a flat and black nose with little or hardly any intelligence. A time will doubtless come when these animals will know how to cultivate the land well, beautify their houses and gardens, and know the paths of the stars: one needs time for everything.When comparing Europeans to Niggers, Voltaire compared them to different breeds of dog:
The Negro race is a species of men different from ours as the breed of spaniels is from that of greyhounds. The mucous membrane, or network, which Nature has spread between the muscles and the skin, is white in us and black or copper-colored in them.Knowing what we know about the human body today, I'd say a better comparison would be between a domesticated dog and a wild jackal.
(http://www.metmuseum.org/toah/images/h3/h3_1972.61.jpg)