LAUSR

In 1835, a statistical account of two treatments of bladder stone had been submitted for consideration by the Académie des Sciences. It compared the traditional extraction of the stone after cutting into the bladder to the innovative crushing of the stone by lithotripsy. A Commission of the Academy was charged with reporting to its members. It consisted of two elderly gentlemen, Napoleon’s legendary surgeon Dominique-Jean Larrey (b.1766) and the physician François Double (b.1776), and two comparatively younger members, Siméon Denis Poisson (b.1781), the mathematician, and the chemist Pierre-Louis Dulong (b.1785), now the Academy’s secretary. The Rapport appeared on 5 October 1835. It disapproved of any application of calculations to medical problems. Rapporteur François Double’s principal objection to numerical analysis was based on the suppression of individual differences required by the method: ‘In statistical matters . . . the first care before all else is to ignore that a man is an isolated individual and only to consider him as a fraction of the species’. A second point was the practical unfeasibility: The need for a large number of facts [still, how many?] could never be met. The method was ‘inappropriate to elevate the human spirit to that mathematical certainty found only in astronomy’. This Rapport was considered relevant enough to be reprinted and commented on in 2001 by the International Journal of Epidemiology. Poisson – by now a renowned mathematician – was not convinced by these objections nor by the allegedly insuperable difficulties of mathematising medicine. He was a probabilistic thinker. It was indeed only during these years that this versatile mathematician was dealing with the calculus of probabilities. In consequence, he was to publish two years later his respective contribution highlighting again the Law of Large Numbers, already described by Jacob Bernoulli and Laplace (see Parts 1 and 2/ 1). In essence it said that more data reduces uncertainty. The Rapport on bladder stone was the starting point for another long discussion, in 1837, in the Académie Royale de Médecine. Its context and history have been analysed. In what follows, I focus on the probability aspects.