Developmental disorder, racial dissolution: racial typologies of developmental normalcy in early child medicine, 1830s–1860s

Decades before medical definitions of developmental normalcy revolved around statistical averages, nineteenth-century medical scientists identified a non-statistical “normal” that cohered within racial groups but was not generalizable across them. Using early child medicine treatises and anatomical, physiological, and ethnological texts, this article argues that nineteenth-century child development science was a race-making enterprise. The first sections analyze texts on child development and disease, identifying the racial parameters of developmental norms and the developmental events most frequently associated with racial differentiation: cranial suture closure and puberty. The following sections argue that variable rates of development and the degree of synchronicity between mental and physical development produced racial hierarchies and threatened racial degeneration. By examining “ethnic” classifications of idiocy, in which developmental timing considered typical for Black children was pathologized in White children, this article argues that developmental disorder posed a threat to racial order. As Darwinian evolutionism introduced scientific and social concerns about the historical contingency of racial progress, the clinical management of child development acquired newfound importance as a safeguard for White racial purity. Joining histories of nineteenth-century child development science and antebellum medical cultures with disability history, this article offers a pre-history of “developmental disability” as a racial category.