lO 



Diminution of the expansion and elevation of the ribs 

 in breathing in : 



Pleurisy. 



Pneumonia. 



Intercostal rheumatism. 



Paralysis. 



Hydrothorax. 

 Percussion consists in simply tapping with the ends of 

 the fingers the body of the animal. 



A majority of practitioners use no kind of instrument for 

 this purpose, but placing the middle finger of the left hand 

 in the spaces between the ribs (when they want to percuss 

 that portion of the body), and then striking it with the ends 

 of the fingers of the right hand, listen to the sounds pro- 

 duced. In using percussion as a means of physical diagnosis 

 we note : 



The clearness or dullness of resonance produced. 



The duration of the resonance. 



Its special character. 



The degree of resistance felt. 

 It is indispensable for every student of veterinary medi- 

 cine that he should be familiar with the normal and natural 

 sounds observed in health, and, as far as possible, the reason 

 of the meaning of every sign. 



Two or three very simple facts explain the use of percus- 

 sion in diagnosis. When any solid body is struck the sound 

 elicited varies according to its material, form, size ; and if 

 hollow the condition of its walls and that of its contents. 

 The thorax (or abdomen) of the horse, having a certain 

 general form, size, condition of its walls, and proportion of 

 air, blood, and solid structure in its contents, will give forth 

 a certain degree and kind of resonance. 



Whatever alters either the state of its walls, or the propor- 

 tion of air, fluid, and solid contained within them must give 

 rise to an alteration of percussion-resonance. For example : 

 The more air and the less fluid or solid contained within the 

 parts of the chest which is percussed the clearer and fuller 

 the resonance, and as a general rule the less the resistance 

 to the finger. Any increase in the relative proportion of 

 liquid (as in pleuritic effusion), or of solid (as tuberculiza- 

 tion), must cause a duller or lesser degree of resonance, and, 

 other things being equal, a greater degree of resistance. 

 Thus diminution of clearness and duration of the percussion 



