DISEASES OF THE RESPIRATORY ORGANS. 125 



* expiratory.' Again, disturbance of the relation between 

 the thoracic and abdominal movements may be detected. 

 Thoracic movements in excess may be due to interference 

 with the action of the diaphragm or abdominal muscles, as 

 in peritonitis. Abdominal movements in excess may result 

 from causes impeding the action of the chest- walls, as in 

 pleurisy. 



PALPATION. — By palpation, or the application of the 

 hand to the walls of the chest, we may feel the shape and 

 movements of the walls, and whether there be any tender- 

 ness or not. Occasionally also abnormal sensations, as 

 pleuritic friction, may be felt. 



MENSURATION.— This method is not much practised 

 in veterinary medicine in this country, but is recommended 

 by French veterinarians. 



PERCUSSION. — This method consists in tapping the 

 walls of the body so as to cause them to yield a sound. 

 Percussion may be either direct (immediate), when we strike 

 the surface with the tips of the fingers, or with the knuckles 

 of the closed hand ; or it may be indirect (mediate), when 

 we percuss upon something placed upon the skin. 



In the direct method, which is the more convenient in 

 examining horses, it is best to strike over the surface of a 

 rib, and as perpendicularly as possible. In the indirect 

 method, the intervening body, whether it be a finger or a 

 plesameter, should be pressed closely to the surface of the 

 body. 



If the walls of a cavity containing air be struck, a hollow, 

 resonant, or low-pitched sound is obtained. On the other 

 hand, if a solid mass, as for instance the thigh, be struck, 

 the sound produced is dull, non-resonant, or high-pitched. 

 A very resonant note is said to be tympanitic (fi/mpanum, a 

 drum). 



If the walls of the chest be percussed where the lung is 



