PERCUSSION. 535 



animals, but in these we can easily change the position of the 

 body, and the existence of liquid may be diagnosed from the 

 dulness being always found at the lower part of the thorax. 

 Any circumscribed induration or large cyst in the lung, may 

 give rise to dulness over a limited extent of surface. 



A peculiar sound, called the crack-pot sound, may be 

 elicited by percussion over the chest in certain conditions of 

 the lung. To represent this sound, clasp the one hand in 

 the other so that they may be in contact all round the palm, 

 while between the palms a space is left containing air, then 

 strike the back of one hand against the knee, when the noise 

 of the air escaping closely resembles the crack-pot sound. 

 It occurs when a large cavity containing air opens into a 

 bronchial tube, through a small orifice, and will probably 

 be accompanied by amphoric breathing and cough. 



PALPATION. 



By this term we understand the application of the hand 

 in order to ascertain the condition of a part. It is chiefly 

 important from its assisting in the diagnosis of pleurisy. 

 If an animal is affected by this malady, whether in an acute 

 or chronic form, firm pressure in the intercostal spaces, at 

 the diseased part, will lead to wincing, and in some cases to 

 moaning, especially in cattle. 



MENSUEATION. 



Mensuration, as applied to the chest, consists in the appli- 

 cation of a cord or tape to the similar parts of the two sides 

 of the chest, in order to ascertain whether any difference 

 exists in their relative prominence. For the larger animals, 

 a tape of three or four feet, and for the smaller, of one-and-a- 

 half to two feet, may be employed. One end is placed immedi- 

 ately behind the withers, and the line carried downward to the 



