In this Tuesday, Oct. 30, 2012 photo, a doctor who started practicing medicine in 1955 wears a stethoscope around his neck as he tends to patients in his office in Illinois. Two centuries after its invention, the stethoscope _ the very symbol of the medical profession _ is facing an uncertain prognosis. It is threatened by hand-held devices that are also pressed against the chest but rely on ultrasound technology, artificial intelligence and smartphone apps instead of doctors’ ears to help detect leaks, murmurs, abnormal rhythms and other problems in the heart, lungs and elsewhere. Photo: Associated Press/AP Photo/Jeff Roberson