AUSCULTATION. 497 



respiratory tract, with the normal and abnormal indications 

 which can thereby be elicited. 



Auscultation. This term, in medical language, indicates 

 the method of ascertaining the condition of any organ of the 

 body by means of sounds conveyed to the ear, when applied 

 over the region in which such organ is situated. This method 

 of diagnosis was discovered by the immortal Laennec, who by 

 this means conferred a lasting benefit on medical science, 

 which it is perhaps impossible to exaggerate. By this means 

 morbid conditions, hitherto only guessed at, can now be 

 ascertained with almost mathematical accuracy, and rational 

 therapeutic measures applied, where our ancestors would 

 have groped along in helpless darkness. 



Auscultation is either immediate or mediate. Immediate 

 auscultation is that in which the ear is applied directly upon 

 the surface of the body, or with the intervention of a hand- 

 kerchief, or other thin cloth. Mediate auscultation is that 

 in which the sound is conveyed from the body to the ear by 

 means of an instrument called a stethoscope. The stethoscope 

 in common use is a hollow cylinder of soft wood cedar or 

 ebony or of gutta percha, varying in length from five to 

 seven inches, and having a bore of about a quarter of an inch. 

 At the end applied upon the skin, it is widened out so as to 

 form a funnel with a hollow diameter of an inch. The oppo- 

 site end has a flattened or slightly rounded form, with an 

 orifice in the centre for the conduction of sound. Dr Pen- 

 nock has introduced a flexible stethoscope, made like the 

 flexible ear-trumpet, and provided at its extremities with two 

 pieces of ivory similar in form to the ends of the more com- 

 . mon instrument. This apparatus is more difficult of appli- 

 cation, but in certain cases, as in cardiac disease, it possesses 

 this advantage over it, that it conveys the sound, without the 

 impulse, of the organ examined. 



2K 



