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The graphic method: the study of movement

Born in France in 1830, Marey trained to be a doctor, but found the new science of physiology more suited to his taste for pure research and to his talents - Marey was a mechanical genius. A positivist, drawn to the intellectual world of the German organic physicists, Marey believed he could make physiology a more exact science - the equal of physics and chemistry, the most advanced sciences of his day - by using machines to measure the functions of the body, so as to determine the laws that governed them. At the root of Marey's idea was a radical perception of the human body - he saw it as a machine, an animate machine, whose workings could be explained by the laws of theoretical mechanics. More radically, he defined the life which animated this animal machine as a complex motor which, like inanimate motors, consumed fuel and supplied energy - a motor, in fact, whose functions could be reduced to the newly discovered laws of thermodynamics.


Ultimately Marey confined himself to a single subject: the body's most manifest form of energy - movement; or, as he put it, the language of life itself. But it was a language that no one had yet deciphered. Marey had chosen to explore a domain in which the unaided senses were powerless.


Marey's great achievement was to adapt the graphing machines used in physics to record motion within and of the body without recourse to the hand or eye. He began by graphing the internal dynamics of the body and then he charted the body’s external kinetics. At the end of his life he studied the media through which these moving beings moved, the eddies and ripples in air and water. In every case he had the movement make its own tracings through instruments he created.

The first instrument Marey constructed, the sphygmograph illustrates the principles to be found in all those that followed, including his photographing instruments.

The sphygmograph, transcribed the manifest sign of circulation, the pulse, and it was Marey's great contribution to cardiology. It was both light, so as not to interfere with what it was describing, and simple. Its lever and stylus converted the heartbeat into a permanent, fluid inscription on a piece of smoke-blackened paper.