Questions of the Day and of the Fray number 4: Pearson, Karl. 1911. The Fight Against Tuberculosis and the Death-rate from Phthisis (London: Dulau and Co.). 35 pp.
Summary
This publication is a sharp critique of public health claims regarding the causation of tuberculosis, particularly challenging the view that sanitary precautions or institutional treatments (like sanatoria) are the primary cause of the falling phthisis death rate. Pearson argues that prevailing medical opinion confuses “association with causation”. He critiques proponents (like Dr. Charles Mercier and Dr. Newsholme) who rely on subjective “belief” and vague language (“reasonably expected,” “justified expectation”) instead of rigorous statistical analysis. Pearson contends that the emphasis on isolation risks turning sanatoria into “leper-houses” rather than facilities for cure.
Using statistical graphics of death rates over time (1847 to 1910), Pearson shows that the fall in the phthisis death rate, unlike the general death rate, retarded during the third period (post-1894). This crucial period coincided with widespread knowledge of the tubercle bacillus and the active anti-consumption campaign involving sanatoria and tuberculin. Pearson strongly suggests that constitutional susceptibility is a more vital factor in causation than mere exposure to infection. He supports this using German post-mortem statistics, which demonstrate that a large percentage of the population have recovered from tuberculous lesions, indicating a natural defensive power. He also references studies in Vienna using tuberculin tests, which suggested that over 90% of children past the age of 11 showed signs of tuberculosis. Pearson stresses the need for public health reports to use modern statistical methods, including correcting correlations for the essential factor of time.
Questions of the Day and of the Fray number 4
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