Monaural stethoscope dating from 1870. The stethoscope is made of gutta percha with a rubber ring at the earpiece end which also functions as a percussor. French physician, Rene Theophile Hyacinthe Laennec originally invented the monaural stethoscope in 1816. This design is essentially a hollow cylinder. The small, bell shaped end is placed on the patient's body and the flat end is the earpiece. Monaural stethoscopes were the earliest form of diagnostic device for listening to internal sounds of the body (auscultation).