Louis Agassiz and Polygenism

Louis Agassiz, circa 1870
Bequest of Dr. Frederic T. Lewis to the Library of Harvard Medical School, 1951

"Permanence of characteristics in different human species" from Louis Agassiz's A journey in Brazil by Professor and Mrs. Louis Agassiz. Boston : Ticknor and Fields, 1869, c1867.
Gift of W. M. Boothby, M.D., to the Boston Medical Library, 1916
The full-text of this item is available through the Internet Archive here.

In 1865, Louis Agassiz and his wife travelled to Brazil and subsequently published this account of his experiences and scientific research there. One of the appendices to A Journey in Brazil emphasizes Agassiz's view on polygenism:
What struck me at first view, in seeing Indians and Negroes together, was the marked difference in the relative poportions of the different parts of the body. Like long-armed monkeys the Negroes are generally slender, with long legs, long arms, and a comparatively short body, while the Indians are short-legged, short-armed, and long-bodied, the trunk being also rather heavy in build.... So far as my observation goes, the essential difference between the Indian and Negro races, taken as a whole, consists in the length and square build of the trunk and the shortness of limbs in the Indian as compared with the lean frame, short tryunk, deep-cleft legs, and long arms of the Negro.
Naturalist Louis Agassiz (1807-1873) became a professor at Harvard's Lawrence Scientific School in 1847 and remained at the university in Cambridge for the rest of his life. He became convinced of the validity of the theory of polygenism--that there was a plurality of origins of the human races. Defenders of slavery used polygenism to maintain that the different races were completely and genetically distinct and that slavery was a natural condition for an inferior race.