The concept of the stethoscope came from an incidence with a young woman on September 13th, 1816, when he hesitated to put his ear on her chest and then rolled paper into a kind of cylinder and applied it to the chest and his ear.
Laennec also found the second heart sound for the first time, although this does not seem to be well known.
I am a big fan of the stethoscope because it enables cardiologists to communicate directly with the heart. The heart is so talkative, murmuring a lot in the center of the body.
Nothing gets me excited more than attempting to understand the heart language.