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.

    17/26 (page 907)
    Then, inspiration may be harsh, while expiration is prolonged. Here only one ear hears the inspiratory sound ; both ears hear the expiratory murmur, and, again, only one ear hears expiration, viz., the ear which heard inspiration. And, eighthly and lastly, inspiration may be harsh, while expira¬ tion is prolonged and harsh. In this case both sounds of respiration are heard by only one ear, viz., the ear connected with the affected side.1 We can easily distinguish this acoustic condition from the simply harsh inspiration and expiration, by the length of the ex¬ piratory murmur, which is sometimes more than twice as long as the inspiratory.2 In conclusion, I may observe that I have never seen an alteration in the inspiratory murmur without some change in expiration. Normal expiration, with abnormal inspiration, so far as my experi¬ ence goes, either does not exist, or, if it does, is so slight as to escape detection,3 with even the differential stethoscope. For detecting the signs which accompany the second stage of phthisis, the differential stethoscope does not prove of such value as in the first and third stages of that disease. Humid crepitation, or the subcrepitant rhonchus, however, is better heard with the dif¬ ferential stethoscope than with the single one, the sound being clearer and fuller. Moreover, the deficiency, generally well marked, of respiration at the base of the diseased lung is ascertained very clearly by Dr Alison’s instrument. Thus, if humid crackling be discovered at the apex of the right lung, and the cups of the dif¬ ferential stethoscope be placed respectively over the bases of both lungs, we shall hear loud breathing—puerile, perhaps, because of compensatory action—with the ear connected with the left (healthy) lung, while no sound whatever will be heard by the ear connected with the right or diseased lung. But humid crepitation is so easily heard by the unaided ear or the uniaural stethoscope, that the differential stethoscope is of comparatively small assistance in detecting it. When bronchial respiration exists, the ear connected with the healthy lung hears nothing, while the other ear hears loud tubular breathing, which sounds so intense through the differential stetho¬ scope as to partake somewhat of the character of blowing respiration. 1 Of course, the value of prolonged expiration as a sign of phthisis will be very much enhanced if, in addition to it, we hear humid crepitation, or sibilant rhonchus, or when (the left lung being affected) we hear the whiff of the pul¬ monary artery at the second and third left costal cartilages, or, lastly, when (the right lung being diseased) we distinctly hear the heart sounds under the right clavicle, and sometimes even at the apex of the right lung posteriorly. 2 Harsh respiratory sounds generally exist at the commencement of phthisis, but later on these sounds become weaker, instead of being louder, than the healthy standard. 3 The same thing has been observed by Fountet in regard to bronchial breathing: “ Jamais je n’ai vu le caractere bronchique, normale ou morbide, exister pendant Vinspiration senlement.'1'—Recherches Cliniqiies sur VAuscultation, p. 58.