The pulse has been regarded as the basic sign of life across most times and cultures, and feeling the pulse is a standard part of all the great medical traditions. The search for a more standardised method of determining and visually displaying the movement of the blood around the body led to the development, from the 1860s, of sphygmographs, sphygmomanometers and the less successful sphygmometers.
In 1881 the English physician and homeopath, Robert Ellis Dudgeon introduced a new, highly portable Sphygmograph. Dudgeon’s Sphygmograph was strapped to the wrist. The pulse at the wrist caused a metal strip to move a stylus, transmitting a record of the pulse onto smoked paper.
(Source Image URL from Making the Modern World)
Dudgeon’s instrument quickly became popular since it was compact and easy to use. The sphygmograph traces an undulating line, which represents a record of blood pressure and pulse over time.