This quick note comes as the result of a short chase on the detection of the pulse and the ability to determine death--as far back and even before Pliny life was determined by the audible heartbeat, which is where the trouble began, because one can still be very alive with a faint heartbeat. This was a major concern when dealing with folks who were thought to have expired, because in the mid-19th century and before the instruments necessary to make a careful and accurate appraisal of whether the heart was still working were yet finely developed. Laennec's stethoscope appeared around 1816, but as much of an improvement as it was this instrument awaited considerable refinements before a truly solid identification of a non-working heart could be established. The gaps in the determination of the arrival of death led to mortuaries where the supposed-dead were left to themselves at room temperature for three days, awaiting the ultimate determination of death which was putrefaction (as in the Munich and Frankfurt Leichenhaus and the Vienna Zentralfriedhof). Earlier in the history of the determination of death methods were quicker and more brutal (if the patient was still alive) involving bellows-driven tobacco-smoke enema, as well as tongue pulling and nipple twisting. (See an earlier post here on the Worst Jobs of the Nineteenth Century for more on this.)
This led to Etienne Marey (1830-1904), a versatile experimenter and premier instrumentalist who was a scientist, physiologist, and motion-picture/chronographer pioneer, who in the 1880's created what was essentially the world's first moving-photographic "slow motion" device. One iteration of Marey's apparatus was basically a long series of ganged cameras recording a motion for a simple task at a given time frame and presented on a continuous strip of photographic paper, sort of like a motion picture with the camera speed set at three frames per second. The resulting images were phenomenal and showed people for the first time the exactness of all manners of simple motions--motions that no longer looked so "simple" once all of its aspects could be studied from captured photographic evidence. Even the act of hopping over a small stool or bending to pick up a bucket of water were enormously revealing in a way like Robert Hooke's Micrographia displayed the great detail and complexity of the seemingly simple fly.
Aside fron being one of the founders of cinematography, the other aspect of Marey's interest in capturing and manipulating time was in medicine, where by the time this article of interest in this post was published in 1876 he had already established himself as one of the greatest cardiovascular physiologists. What we find in this review in Nature (Thursday, January 6, 1876) of Marey's Physiologie Experimentale (Paris, 1876) was the editor's keen interest in the mechanical heart Marey had constructed to show the actions and functions of the heart--the first time, the article notes, that all aspects of the action of the heart were exhibited correctly in one model.
Of particular interest was the recording device for the pulse of the heart, which was one in a series of devices such as that improved upon, something Marey himself had done with the first-introduced sphygmograph ("pulse wrtier") of Karl von Vierdodt in 1854. The 1875/6 Marey instrument made major advancements in continuous graphical registration in instruments of continuous noninvasive arterial responses.
[See also Marey's La Methode Graphique dans les Sciences Experimentales et Principalement en Physiologie et en Medicine, 1878