William See

“ The respiratory movements coincide generally with the heart's action: all respiration ceasing, the heart never continues to act longer than five minutes, and these movements can be noted by the non-medical observer, by placing a piece of looking-glass, or a dish filled with water or mercury, upon the chest, and allowing the light to be reflected upon the surface; the slightest movement will result in oscillations.
A common mistake of death for a supposititious trance state is the continued or increased warmth of the body, which is so remarkable in some cases ”

“ For the existence of a trance state sufficient to simulate death, all appreciable movements of respiration and circulation must be suspended for a considerable length of time, and there is but one properly authenticated case on record as accepted by physiologists ”

“ That the trance state has been mistaken for death, and that premature burials have taken place, seem to be fully recognized in the system of morgues or dead-houses in various parts of Europe where bodies are so placed that the slightest movements will be brought to the notice of attendants; and in the laws which in most countries require the lapse of twenty-four hours and longer periods between death and burial. Yet competent authorities tell us that such institutions (morgues) are superfluous when ordinary care is taken by the relatives of a deceased person ”

“ Medical jurists, after carefully examining all evidence that can be accepted upon such cases, have concluded that it is impossible to suspend animation or to simulate the same, without detection by the ordinary means, for so long a space of time as one hour ”