Medical Antiques Online has photos and information on the history of the stethoscope. Rene Theophile Hyacinthe Laennec invented the stethoscope in 1816 after divising an alternate method of listening to the heart of a young woman. As he was unwilling to place his ear on her chest, he rolled up 24 sheets of paper, placed one end on her chest, listened at the other, and was happy to find that the sound was magnified. The site includes his own description of his discovery that led to the invention. He created the first stethoscope using a wood-turning lathe. ‘Binaural’ models (for both ears) came to market in the 1850s.