a wooden cylinder about eighteen inches long, invented by M. Laennec of Paris in 1823, and used by modern medical practitioners to ascertain the healthy or morbid condition of the organs within the chest. It is well known that wood is an excellent conductor of the vibrations that give the sensation of sound, and that, if a person scratch one end of a log of wood many yards in length, another person, by putting his ear to the other extremity, will distinctly hear every sound emitted. On this principle, the stethoscope has been invented. It is now frequently made of gutta-percha. The heart, by its violent and incessant action, imparts a motion and thrilling to the walls of the chest, which an observer can loudly hear by applying the ear to the left side; and the Stethoscope enables him to obtain the same information, with less trouble to the patient, and without anything disagreeable to the most delicate feelings. Hence, those who are well practised in the use of the stethoscope, and who have compared their observations on the living body with the appearances found in the dead bodies of those who have died of diseases of the heart, are enabled to detect enlargement of that organ, ossification of its valves, or aneurism of the great vessels. In diseases of the lungs, likewise, and even of the abdominal viscera, the stethoscope is a most valuable means of diagnosis.