On the differential stethoscope and its value in the diagnosis of diseases of the lungs and heart / by George L. Carrick.

  • Carrick, George L., 1840-1908.
Date:
[1873]
Catalogue details

Licence: Public Domain Mark

Credit: On the differential stethoscope and its value in the diagnosis of diseases of the lungs and heart / by George L. Carrick. Source: Wellcome Collection.

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    intensity of the acoustic impression has had time to die out of his mind,—to such an extent, at any rate, that he is unable to pro¬ nounce positively which of the two sounds is the greater I have on more than one occasion heard two good auscultators disagree as to whether respiration was weaker in the right or in the left chest. The differential stethoscope generally proved that it was equal on b°Thedgreat advantage of the differential stethoscope, therefore, over all others is, that by allowing us virtually to place each ear on a different part of the chest at the same time, it enables us to differentiate sound easily, t.e., to recognise the stronger from the weaker. By its means respiration and vocal resonance are heard louder and clearer than with any other stethoscope—Cammann s, which equals it, excepted; and with its aid we can auscultate the chest much quicker and with less fatigue to the patient, as well as ourselves, than either with the uniaural or Cammann’s instrument. Thus, with the two cups the supraclavicular and the upper scapular region can be auscultated at once ; by placing the cups side by side over any other region, we hear the breathing over double the surface that we do with any other instrument , and, lastly, we can keep our head in an easy position while examining the patient. I have dwelt thus long upon the physical properties of the differential stethoscope, and have even risked occasional repetition, because I think these properties should be thoroughly understood before passing on to a consideration of . The Value and Uses of the Differential Stethoscope in the Diagnosis of Chest Diseases.—The differential stethoscope, while useful in the diagnosis of all pulmonary disorders, is most valuable in . its application to phthisis in the first and third stages of that affection, —in those stages, viz., where not unfrequently a just comparison between the relative intensity and duration of two sounds affoids us the only means of arriving at a correct opinion regarding the state of the lungs. Let us, to begin with, take the first stage of phthisis, in which there may be a change, 1st, in the intensity of the vesicular murmur; 2d, in its duration 5 3d, in its quality; 4th, in its rhythm ; and, 5th, in its pitch. blow, any alteration in the quality, rhythm, and probably pitch, of the respiratory murmur, can be as well detected with the ordinary stethoscope as with the differential one. It is when we have to estimate the intensity and duration of pulmonary sounds that the differential stethoscope affords us such marked assistance. .It will therefore be necessary to enumerate briefly the changes which the breathing undergoes in regard to strength and length. Thus, the ordinary vesicular respiration may, on the diseased side, be altered in intensity and duration in the following manner:— ls£, Both inspiration and expiration may be harsh. 2d) Both inspiration and expiration may be feeble. 3d, Inspiration may be normal, while expiration is prolonged. 4th: Inspiration may be