Benjamin Rush (1745–1813), a physician, proposed that being black was a hereditary skin disease, which he called “negroidism,” and that it could be cured.
Rush believed non-whites were really white underneath but they were stricken with a non-contagious form of leprosy which darkened their skin color. Rush drew the conclusion that “whites should not tyrannize over [blacks], for their disease should entitle them to a double portion of humanity.
However, by the same token, whites should not intermarry with them, for this would tend to infect posterity with the ‘disorder’… attempts must be made to cure the disease.” Despite this inconvenient fact, Rush was an abolitionist who wrestled with various contrarian viewpoints.
Believe it or not, “negroidism” is not what history celebrates most about him. Can you guess his other claim to fame?