Illustration of the first stethoscope (left) next to lungs infected with tuberculosis. The stethoscope was invented in 1816 by French physician Rene Laennec and it was a significant development in modern medicine. Laennec discovered that using his device was superior to the typical method of placing the ear over the chest when diagnosing diseases such as tuberculosis. He created a detailed manual on how to use the instrument which included this diagram. It bears little semblance to the modern stethoscope, consisting of a simple cylinder made from wood and metal. This elementary first design was soon improved, and the stethoscope eventually became the one instrument common to all doctors worldwide. Published in 'A treatise on the diseases of the chest, and on mediate auscultation' by Rene Laennec in 1819.