Philadelphia, Feb. 17,1895. To the Editor: —The interesting communication of Dr. A. M. Corwin, in theJournalfor Feb. 16, 1895, upon a double binaural stethoscope prompts me to send you the accompanying cut of a multiplex binaural stethoscope, which I have been using with much satisfaction to the class and myself, at the Jefferson Medical College Hospital for some months. By means of this instrument, which was made at my request by Mr. William Willis, a well-known instrument maker of Philadelphia, sixteen students can listen to the heart sounds or any other physical signs demonstrable by auscultation, if these sounds are not so indistinct as to be heard with difficulty even when using a single instrument. With large classes the difficulty is that only two or three men can listen to the heart sounds, while the description of the case is fresh in their memories, but with this multiplex