A Dudgeon’s Sphygmograph. Blood pressure is now measured and recorded by accurate digital sphygmomanometer’s but this is an example of early blood pressure measuring device called a Sphygmograph. It is strapped to the wrist and the pulse beat is transmitted to a lever which records the fine movement onto a ‘smoked paper’. The first efficient Sphygmograph was designed by Étienne-Jules Marey in 1863. But this example is a Dudgeon's sphygmograph. This improved sphygmograph was ‘invented’ by Dr. Robert Dudgeon a Scottish trained physician, in the late 1880’s. Dudgeon changed Marey’s original design which was heavier and made it more portable. Sphygmograph’s started to visually demonstrate blood pressure and soon became valuable diagnostic aids. They were the predecessors of the modern arm cuffs that Doctors now use to measure blood pressure. Dudgeon himself wrote of his work - The Sphygmograph: its history and use as an aid to diagnosis in ordinary practice in 1882

The piece is in good cosmetic condition and the stylus responds when dial is moved. The unwinding mechanism will need to be serviced to make the roller work that advances the paper. It is a rather simple mechanism that a watch repair service can repair if you’d like this back to full function . Comes in original leather case with paper and metal tray that holds the paper. No straps on the Sphygmograph. A great historical teaching device to have in any serious cardiovascular reference library.