To the Editor of The London Medical Gazette, August 12, 1829

Description of Comins' stethoscope:

"It consists of two tubes, (A,B), each 7 inches in length, and 5/8ths of an inch in diameter, except at the part to be applied to the thorax, where the diameter of the aperture is and inch and a half. These pieces are united by a perforated joint, (C,D), three inches in length, at right angles to their extremities : and the two pieces of which the joint consists, being united like the joint of a flute, permit the limbs of the cylinder to form any angle. The upper end of the instrument is provided with an ear-piece, (E), sufficiently large and concave to envelop the ear. Its central portion, (F), being angular and moveable, admits the extremity of the cylinder as nearly as convenient to the meatus auditorius externus. The ear-piece can, by means of a moveable joint, (G,H), be placed laterally with respect to the extremity of the tube. The moveable joints, (C,D--G,H), were they formed of brass, could, by a simple contrivance, be rendered in any position air-tight. But as this, and perhaps every substance that would deviate from the homogeneousness of the cylinder, would injure the sound, external securities arenecessary. The following has been devised : each joint is covered by a metallic ferrule, (iii) 5/8ths of an inch in length, and 6/8ths of an inch in diameter, except at one extremity, (J), where it is reflected inwards, at right angles, and where the diameter reaches about 3/16ths of an inch. Within the ferrule, and in contact with the reflected extremity, is placed a small flat ring, (K), which is secured through an aperture in the ferrule, (L), at three points, to one side of the joint, (M.) The other end of the ferrule is screwed also at three points to the other side of the joint, (N). The ferrule, and the inclosed ring, are by this contrivance permitted each to move freely with respect to each other ; while with respect to the joint, they preclude the possibility of its opening, or of its not being air-tight. Should friction, however, eventually cause it to become too free, the screws can be withdrawn from the pieces, (D,G), and by means of silk coiled in the depressions, (O,O), the joint can again be rendered air-tight. The piece of ivory that is screwed to the lower extremity of the cylinder is externally somewhat concave, in order that it may be more advantageously applied to the thorax. The ivory ferrules, and the pieces to which they are screwed, and each marked with corresponding circles..... "

Earliest known description of a binaural stethoscope:

".....It is surprising that the discoverer of mediate auscultation had not suggested a flexible instrument. But Laennec, like the immortal Archimides, grappled with great ideas in unexplored regions of thought. Contented with the acquisition of all the knowledge attainable by the stethoscope, he despised the drudgery connected with the minutiae of mechanical invention ; directed his thoughts to great pursuits ; and permitted the instrument to be modified by the humblest of labourers in the field of science.

It had occurred to the writer that both ears might be simultaneously and advantageously employed in stethoscopic examinations. The instrument (Comins') adapted to this purpose consists of a tube, connected at its middle at right angles to the cylinder, to be apllied to the patient, and connected at its movable extremities to two tubes, moveable also on teh principle that has been described. It admits of easy adaption at once of the patient, and to both ears."

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