Alexander Lesassier Hamilton’s 1816 report of a controlled trial of bloodletting

In 1816, a military surgeon – Alexander Lesassier Hamilton – used his Edinburgh University MD thesis on fever to describe an experiment in which rotation had been used to create comparison groups in an assessment of the effects of bloodletting. The experiment reported by Alexander Lesassier Hamilton took place when he was serving in the (allied) Portuguese Army during the Peninsular War. It involved 366 sick soldiers treated by three surgeons, one of whom used bloodletting, two of whom (including Lesassier Hamilton) did not. Rotation was used to assign the patients to one of the three surgeons, thus generating similar comparison groups. The crucial paragraph (which is at the very end of Lesassier Hamilton’s MD thesis) reads as follows: