It will facilitate study of the phenomena of heart action and the effect of drugs on that vital organ. The chronograph opens the way to the accurate measuring and recording of the speed and variation of human heart beats over long periods, even during the sleeping hours of the subject, which is expected to prove of great value to physiologists and criminologists. The heart of the recent demonstration was that of a turtle, removed from the reptile while alive, freed of all extraneous tissue and suspended in a physiological salt solution exactly duplicating body conditions. In this state the organ continues to beat for thirty-six hours, at the same time setting down, by means of the chronograph, a graphic history of the approximately 72,000 pulsations it makes in that time. With each beat the tiny organism pulled down a little lever that dipped a fine filament into a drop of mercury and made a contact that transmitted an electric impulse to the chronograph. There it was translated to a fraction of a second into a record inked on a chart. Introduction into the solution of nicotine--one part in 10,000--and of adrenalin--one part in a billion--was immediately noted by a marked retarding of the heart tempo in the first case and swift acceleration in the second. Use of the chronograph to study the action of any heart that can be removed from the living body is possible, the scientist said, adding that a comparatively simple adjustment will make possible recording of the human heart by a device applied to the chest. Application of the instrument to tests of human nerve reactions and to psychological tests is forecast. * * * * * End of Project Gutenberg's Astounding Stories, August, 1931, by Various