Percussion. 159 



In examining the chest the two sides should be compared and if 

 allowance is made for the dulness felt in the lower half immedi- 

 ately behind the left elbow caused by the position of the heart, 

 and the deadness of the sound on the last few ribs on the right 

 side where the liver is situated, any further deviation from a bi- 

 lateral symmetry of sound is indicative of disease. The general 

 resonance will be decreased by a full stomach which prevents the 

 full inflation of the lungs, and it will be increased if the animal 

 stands on a wooden floor with an empty space below. A short 

 statement of the degrees of resonance over the different parts of 

 the chest in the various races of the domestic animals in a state of 

 health may prove useful. 



Horse. — Left side. In the upper third the resonance is full 

 behind the shoulder. It diminishes from the 13th rib backward 

 and from the decreasing thickness of lung the blows should be- 

 come less and less powerful. In this space forcible striking brings 

 out the drum like resonance of the abdominal organs. 



In the middle third the sound over the 5th and 6th ribs is dis- 

 tinct but not full ; it increases to the nth rib and then decreases 

 to the last. 



In the lower third a very slight resonance may be observed 

 over the 4th rib. ; over the 5th, 6th, and 7th, where the heart 

 approaches the surface the sound is dead ; while from this to the 

 13th rib a slight resonance may be made out. 



Right side. The upper third resembles that on left side from 

 the shoulder as far back as the 13th rib behind which anything 

 above the gentlest blows brings out a drum like sound from the 

 large intestine (double colon) especially. This is clear when 

 that is distended with gas. 



In the median third the resonance resembles that on the left 

 side. In the lower third it equally corresponds as far as the 

 seventh rib behind, which sound is dull because of the proximity 

 of the liver. 



Ox. — Left side. The upper third is clear in sound from the 

 eighth to the tenth ribs, and behind this by gentle tapping to the 

 second last (twelfth). Forcible striking, however, brings out the 

 drumlike sound of the upper sac of the paunch which always 

 contains more or less air. 



The middle third has a clear resonance as far as the .seventh 



