Hoffman knew his work was “a most severe condemnation of moderate attempts of superior races to lift inferior races to their elevated positions.” He rejected that sort of assimilationist racism, in favor of his own segregationist racism. The data “speak for themselves,” he wrote. White Americans had been naturally selected for health, life, and evolution. Black Americans had been naturally selected for disease, death, and extinction. “Gradual extinction,” the book concluded, “is only a question of time.