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

Piece mechanism works when you wind it up and when placed on wrist the needle corresponds with heart beat on the vein. Strap is in good worn condition and comes in original velvet lined box bottom --top is missing on the box.