Auscultation. 175 



on the side of the chest, the sound is short, dull and indistinct. 

 When the lung is more solid from hepatisation, pleural exudation 

 or other cause, or when the bronchi are dilated the sound is loud 

 and strong. The extent over which it may be heard thus forcibl}- 

 agrees w^ith the area of lung in a state of consolidation. When a 

 considerable cavity or canal communicates with a bronchial tube 

 and extends to near the surface of the lung the sound is loud and 

 rmging. The note is specially clear and metallic when such a 

 cavity opens into the bronchus by a narrow orifice ; an apt illus- 

 tration of this noise may be obtained by coughing into a narrow 

 necked vessel. 



The results obtained by auscultation should be confirmed by 

 percussion before arriving at any definite conclusion as to the state 

 of the chest. Consolidated lung tissue is a much better conductor 

 of sound than the healthy, and sounds conveyed through this may 

 be heard at a considerable distance from their point of origin. 

 Thus the heart sounds are frequently heard over any part of the 

 right side of the chest, and crepitation and other sounds may be 

 heard in the centre of a hepatized portion. On all such occasions 

 the dull sound elicited on percussion will not fail to correct the 

 fallacy. 



PALPATION. TOUCH. 



This is chiefly useful in cases of pleurisy. As already noticed 

 the vibration of the chest walls which accompanies the early fric- 

 tion sound is sometimes perceptible by the hand applied on the 

 side of the chest. Pressing firmly in the intercostal spaces at the 

 affected part invariably causes wincing and in cattle grunting. 

 Pinching the back in inflammatory chest diseases in cattle but 

 e.specially in pleurisy has a similar effect. 



MENSURATION. 



Measurement of the chest gives less reliable results in the lower 

 animals than in man. A cord four feet long should have one end 

 placed on a definite point on the withers and not removed until 

 both sides have been examined. It should be first carried down 

 to a point in the middle of the breast bone and the distance 

 marked by a knot ; a comparison may be made by carrying to the 

 same point over the opposite side. It should next be carried sue- 



