Auscultation. 189 



than in the Norman, Clydesdale and other heavier breeds. Deep, 

 broad capacious chests emit a stronger sound than such as are 

 shallow, narrow and short. Exercise, fear or any excitement 

 accelerating the respiratory act increases the sound. A full 

 stomach, certain narcotics and other depressing influences lessen 

 it. Other things being equal the sound is lower in cattle and 

 sheep than in other domestic animals. 



Horse. The ear pressed strongly upon the breast where the 

 windpipe enters detects a strong blowing sound referable to the 

 lower end of the trachea and the bronchi. In young foals a 

 respiratory murmur is heard when the stethoscope is applied in 

 front of the shoulder, the limb being meanwhile drawn backward. 

 A similar murmur may be heard, but less distinctly over the 

 shoulder blade at this age. 



Left side. Behind the shoulder in the upper third of the chest 

 the sound is loud and somewhat harsh, the respiratory murmur 

 being here supplemented by the noise of the air rushing through 

 the larger bronchia. From the 1 3th rib the respiratory sound is 

 alone heard and becomes weaker to the second last (17th). 



In the middle third the respiratory murmur is moderately clear 

 from the 4th to the 6th rib, it becomes louder and clearer to the 

 9th from which its force gradually diminishes and is lost over the 

 i6th. In the lower third over the 4th, 5th, and 6th ribs the re- 

 spiratory sound is replaced by the sounds of the heart, each beat 

 being distinctly divided into two sounds, the first dull and pro- 

 longed, the second short and quick. The respiratory murmur is 

 heard over the 7th and 8th ribs, is weaker on the 9th and lost 

 over the loth. In the middle and lower thirds, but especially 

 towards the posterior part of the chest, abdominal sounds are 

 •often heard. They consist chiefly in gurgling or in a noise like 

 that caused by the air rushing into a bottle which has been 

 turned upon its side when full of water. Such sounds are easily 

 distinguishable from those occurring in a diseased chest as they 

 bear no relation to the rhythmical action of breathing. 



Right side. In the upper and middle thirds the sounds do not 

 differ from those of the left side. In the lower thirds the respira- 

 tory sound is clear from the 4th to the 7th ribs ; from this it de- 

 creases and is lost at the loth. 



Ox. In very lean cattle the respiratory murmur heard in front 



