‘If experts differ, what are we to do in the matter?’ The Medico-legal Investigation of Gunshot Wounds in a 1927 Scottish Murder Trial

This article uses a notorious criminal trial, that of John Donald Merrett for the murder of his mother, as a case study to explore forensic medicine’s treatment of gunshot wounding in pre-war Scotland. This topic, which has hitherto received little attention from historians, provides insight into two issues facing the discipline at this time. First, the competing attempts by prosecution and defence expert witnesses to recreate the wound in a laboratory setting, in order to determine the distance from which the shot had been fired, exposed the uncertainties surrounding the application of a well-known laboratory technique for which no fully agreed-upon protocol existed. Secondly, the case allows the examination of the working relationship of a medical expert and a gunsmith, in which disciplinary boundaries became indistinct and the wound a shared site of analysis, in a period before the separate profession of forensic science became institutionally grounded in Scotland.