V. Note on the invention of a method for making the movements of the pulse audible by the telephone. The sphygmophone

While experimenting with the audiometer, it occurred to me that I might get a secondary or telephonic sound from the movements of the pulse at the wrist. I have effected this in a very simple manner, by adding a microphone to a Pond’s sphygmograph. I mount on a slip of talc, glass, wood, or ebonite a plate of metal or gas carbon. I place the slip in the sphygmograph as if about to take a tracing of the pulse