Of lice and men: Charles Darwin, Henry Denny and the evidence for the human races as varieties or species

Abstract Charles Darwin never doubted the common ancestry of human races. But he was open-minded about whether races might nevertheless be so different from each other that they ought to classified not as varieties one species but distinct species. He pondered this varieties-or-species question on and off for decades, his time aboard Beagle through publication Descent Man . A constant throughout concern with something first learned voyage that, face it, seemed favour ranking: races, told, play host lice. This paper reconstructs long run Darwin's reflections interactions race, lice history, using extended correspondence Henry Denny – curator scientific collections Leeds Philosophical Literary Society, Britain's leading expert in natural history a window onto social world whose imprint is everywhere pages