James Mortimer, Holmes's client in The Hound of the Baskervilles, is no ordinary general practitioner. Consulting the Medical Directory, Watson finds him to be the author of several learned essays: ‘Is Disease a Reversion?’, winner of the Jackson Prize for Comparative Pathology, and ‘Some Freaks of Atavism’ and ‘Do We Progress?’, published in The Lancet and Journal of Psychology respectively. It thus hardly seems fair for Holmes to characterise him as a mere ‘country doctor’ (6). Mortimer's publication history is highly revealing, both about his own scientific world view and that of the novel. Keywords in the essays’ titles – ‘reversion’, ‘atavism’ and ‘progress’ – clearly indicate that these are investigations in evolutionary biology. More specifi- cally, Mortimer is interested in the possibility that human evolution can actually go into reverse, producing degenerate specimens of the human race, descending down the evolutionary ladder into the animal kingdom, or afflicted by genetic conditions that cause abnormalities (‘freaks’) or disease.

Blessed with a twenty-first-century view of such pseudoscience, we might conclude that Mortimer is a crank, an impression apparently confirmed by one of his first actions in the story – running his finger along Holmes's ‘parietal fissure’, while exclaiming, ‘It is not my intention to be fulsome, but I confess that I covet your skull’ (8). This causes even Watson to characterise him as ‘strange’. Skulls, we discover, are Mortimer's ‘special hobby’. He claims to be able to read skulls as accurately as Holmes can read typefaces, so that he can easily distinguish ‘the skull of a negro from that of an Esquimaux’ (32). Mortimer's ‘special hobby’ resembles that of a close contemporary, the sinister doctor in Conrad's ‘Heart of Darkness’ (1899), who eagerly measures Marlow's skull ‘in the interests of science’ before the latter's journey into the interior of Africa. Mortimer, however, is a character in a very different kind of tale. Conrad's phrenologist is the scientific representative of a racist, imperialist ideology, exploiting the people and resources of a vast region. Mortimer, if he represents anything in The Hound of the Baskervilles, represents modern science.