Historical information
They sphygmograph was devised as an improved device to measure blood pressure, and was a marked improvement on the first machine of its type. The sphygmomanometer was considered cumbersome and the Dudgeon sphygmograph was smaller, and once placed into its box, could be carried in a pocket. The Dudgeon sphygmograph was introduced in 1881. It was strapped tot he wrist with a metal strip that moved a stylus. This transmitted a record of the pulse onto smoked paper, creating a record of blood pressure.
Physical description
The sphygmograph is housed in a purple-lined, leather bound case with a metal hinge and clasp located halfway up the case. It is constructed from chrome and comprises several moving parts including wires, knobs and handles. A black fabric strap with a metal attachment is also present, used to attach to the patient's wrist.