The introduction of numerical methods to assess the effects of medical interventions during the 18th century: a brief history.

Abstract

Although numerical approaches were used by John Graunt to analyse patterns of mortality in 17th-century London,1 it was not until the early 18th century that numbers began to be used to assess the effects of medical interventions.2–7 This development occurred chiefly, but not exclusively, in Britain.8–27 In 1731, for example, Francis Clifton published a book entitled Tabular observations recommended as the plainest and surest way of practising and improving physick,28 followed by a work entitled The state of physick, ancient and modern, briefly considered: with a plan for the improvement of it.29 Clifton pointed out that, instead of assessing the worth of therapies by whether they accorded with theories, physicians needed to base their judgements about the effects of treatments on a sufficient number of their own (or otherwise testified) observations, organized in tables.30 Clifton was followed later in the 18th century by others emphasizing similar principles: for example, William Hillary's Inquiry into the means of improving medical knowledge;31 Thomas Percival's commentary on the ‘dogmatist’ and the ‘empiricist’ physician in his Essays medical and experimental;32 John Gregory's Observations on the duties and offices of a physician;33 James Sims’ Discourse on the best method of prosecuting medical enquiries;34 a section in John Aikin's Thoughts on hospitals;35 Thomas Kirkland's Inseparability of the different branches of medicine;36 an anonymous author's contribution to Medical Observations and Inquiries;37 Gilbert Blane's Observations on the diseases incident to seamen;38 and George Fordyce's An attempt to improve the evidence of medicine,39 which was published in the Transactions of a Society for the Improvement of Medical and Chirurgical Knowledge. Of course, there is a difference between calls for numerical methods to be applied and actually applying them. However, the principles enunciated by Clifton and others were applied widely in civilian practice in Britain, as well as in the British armed forces.