PHYSICAL SIGNS DRAWX FROM AUSCULTATION. 4-il 



least when in the course of that action certain structural 

 changes have occurred in connection with the plourte, and 

 previous to the more advanced condition of liquid effusion 

 into the cavity, that any sound can be satisfactorily distin- 

 guished. 



In character this friction-sound has been variously described 

 as a mild or smooth rubbing, grating, or crackling noise. It is 

 not uniformly executed, but seems, when heard, as if carried 

 out by short jerks, appreciated during both parts of the respi- 

 ratory act, more clearly in inspiration, and ordinarily at the 

 inferior part of the thorax. It may be regarded as a dry 

 sound, seeing it is only recognised prior to the condition of 

 effusion, and becomes inaudible with the existence of fluid in 

 the chest, and may again be heard when the fluid is being 

 removed. 



In following out the examination of any such sound, when 

 detected, attention ought to be bestowed upon its intensity, its 

 extent or distribution, and upon its relation to inspiration or 

 expiration. 



E. Other Sounds of Varying Character sometimes Heardin connec- 

 tion with Changes in the Thoracic Cavity. — The conditions which 

 seem to favour the production of these unnatural sounds in 

 the chest, and associated with its contained organs, are (a) the 

 presence of a moderate amount of fluid in the cavity of the 

 2)leural sac ; (6) the existence of extensive organizations in 

 different parts of the chest ; (c) a certain quantity of air in 

 contact with the fluid. 



Under such conditions we may occasionally detect certain 

 unnatural sounds, chief of which are metallic tinkling and 

 modified gurgling sounds. 



Metallic tinJding, or the sound indicated by this term, may 

 be tolerably well imitated by pressing the palm of the left 

 hand firmly over the ear, and tapping it smartly with the 

 middle or index finger of the right. It is a sound which is 

 neither heard regularly, nor, when detected, is it of uniform 

 character ; some of the notes or impulses are pitched in higher 

 tones than others, as well as more prolonged. 



It has been regarded as due to the dropping of fluid from 

 the adherent fibrinous exudations into and upon the liquid 

 contained in the cavity. 



