Since my last communication on this subject to the Society, in February, my attention has been directed to perfecting a mechanism for obtaining a record of the vibrations imprinted on the wax cylinder of the phonograph, and I wish to acknowledge the great assistance derived from the ingenuity and mechanical skill of Mr Reid and Mr Kean, of the well-known firm in Glasgow known by the name of “James White.” The instrument now before you, which I shall call a phonograph recorder, traces out, on a large scale, the curves of the indentations on the wax cylinder corresponding to each vibration of sound, and it does so in a way that seems to be highly satisfactory. It is now an instrument that can be used by other workers in this difficult department of research, and I hope that some of the younger physiologists and physicists will take the matter up and apply it to an extent that, with numerous avocations and with calls to other branches of physiological research, I can never hope to overtake.