306 BOVINE PATHOLOGY. 



is a similar state when the larger tubes are involved. Other 

 refinements are distinguishable, but their characters are 

 rather indefinite. The Vesicular sound observed during 

 health depends upon the tension of the walls of the air-cells 

 during inspiration, together with the rush of air through 

 the narrow terminations of the bronchial tubes into these 

 dilatations, consequently it is appreciable also to a modified 

 degree during expiration. It can only be heard in some parts 

 of the lungs, for it is liable to be obscured by the bronchial 

 rushing sound. It is most perceptible in young animals, 

 for with age the cells are much dilated, and the transitions 

 from the tubes less abrupt. Determination of this sound 

 is important, as informing us of the pervious condition of 

 the air-passages and the air-cells. It is early supplanted 

 in cases of inflammation of the intimate structure of the 

 lungs by a peculiar crackling sound known as crepitation. 

 The intensity of these sounds varies with disease ; when a 

 part of the lung is lost for functional purposes the parts 

 which remain pervious give increased sound. Solidifica- 

 tion and deposition between a bronchus and the ear may 

 render its rushing sound more evident. In other cases 

 there is partial or complete loss of sound, due to an im- 

 pervious condition of the passages, as in lung consolidation 

 or collapse, or else to the presence of some bad conductor 

 of the sound, as in cases of hydrothorax. Our diagnosis 

 of the extent of disease also depends upon the stationary 

 or migratory condition of the sounds, as shown by frequent 

 examinations. The movements may be either abrupt, as 

 when some obstruction has been removed by coughing, or 

 gradual, as in hydrothorax. 



The pleura, when inflamed, is the seat of the friction 

 sound, due either to two dry surfaces moving in contact 

 with one another, or to a similar application of two sur- 

 faces roughened by deposition of false membranes. 



Examination of the Chest of the Ox, by Ausculta- 

 tion. — The extra lobe of the right lung extends rather in 

 front of the heart. The thorax is wide and rounded pos- 

 teriorly, but the diaphragm bulges into it to a marked ex- 

 tent, and gains firm attachment to the inner surface of the 



