Eugenics Laboratory Lectures number 8: Pearson, Karl. 1912. Tuberculosis, Heredity and Environment; Being a Lecture Delivered at the Galton Laboratory for National Eugenics, 12 March 1912 (London: Dulau and Co.). 46 pp.
Summary
Delivered by Karl Pearson, F.R.S., in March 1912, this lecture applies biometric methodology to demonstrate that constitutional heredity is the chief factor in tuberculosis susceptibility, forcefully challenging the popular anti-consumption campaigns based on environmental causation and contagion.
Pearson presents data confirming that the parental inheritance factor for phthisis is high (around 0.50), while the association between husband and wife (marital infection/assortative mating) is much lower (around 0.17 to 0.24).
He launches a major critique of public health policy, presenting statistical curves showing that the rate of fall in the phthisis death-rate has retarded since 1891. This period—the third period of public health activity—coincides with the widespread knowledge of the tubercle bacillus and the active “Fight against Tuberculosis,” including the use of sanatoria and tuberculin. Pearson concludes that this “Fight” is based on erroneous premises, as the improved mortality is due to the hereditary development of racial immunity, not the reduction of infection.
Using actuarial life-table comparisons (Table XIII), Pearson shows that sanatoria have not demonstrably prolonged the lives of patients in a “marked or substantial manner”. He criticizes the publication of inaccurate curative claims (e.g., 80% cured) and calls it “cruel” to pursue sanatoria funding based on false hopes when the core idea is likely that of segregation or the “leper-house idea”. Pearson concludes that the eugenist’s proposed action—encouraging the healthy parentage—is the “better thing to do” and would be more effective than spending millions on sanatoria.
Eugenics Laboratory Lectures number 8
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