Nott argues "probable extermination of the two races if the Whites and Blacks are allowed to intermarry."
Josiah C. Nott, "The Mulatto a Hybrid-probable extermination of the two races if the Whites and Blacks are allowed to intermarry," The American Journal of the Medical Sciences, Volume 6, Issue 11 (July 1843), 252-256
The Mulatto a Hybrid—probable extermination of the two races if the Whites and Blacks are allowed to intermarry. By J. C. Norr, M. D., Mobile. …
This I do believe, that at the present day the Anglo-Saxon and Negro races are, according ot he common acceptation of the terms, distinct species, and that the offspring of the two is a Hybrid. …
I have said that the Mulatto is a Hybrid. By this term is understood the offspring of two distinct species—as the mule form the horse and the ass. …
As many of these hybrids are governed by different laws, is it not reasonable that the human hybrid may also have its peculiar laws—may not one of these laws be (which might be inferred from the foregoing data) that the Mulatto or Hybrid is a degenerate, unnatural offspring, doomed by nature to work out its own destruction?