PUI.MONARY EMPHYSEMA IN CATTI^E. 



Causes. This may occur in the lobular or interlobular form 

 from hard work in the yoke or from violent exertion of any kind, 

 such as straining against hobbles when cast (Auacker), a stam- 

 pede, the continuous bellowing of an animal shut up alone, the 

 persistence of a cough from disease of the throat or lungs (pha- 

 ryngeal or pulmonary tuberculosis, tumors in the throat, lungs or 

 mediastinum, lung worms, dusty food, inhalation broncho-pneu- 

 monia, pleurisy from foreign body or other cause, heart disease, 

 lung plague and its sequelae, Rinderpest, etc.), swill-stable feed- 

 ing, tympany of the rumen, traumas of the trachea or bronchia. 



Lesions. These resemble those of the horse, the affected lobu- 

 lettes standing out like small comparatively bloodless bladders on 

 the surface of the lung, more particularly near its lower border 

 and in the forward lobes. There is this marked addition in inter- 

 lobular emphysema that the great profusion of connective tissue 

 between the islets of lung tissue are replete with air and stand 

 out clearly, marbling the lung as in lung plague, and even leading 

 to mistaken diagnosis. This has led to the confounding of lung 

 plague and Rinderpest in former times. The lines of blown up 

 interlobular connective tissue differ from the liquid-infiltrated 

 specimen of lung plague, in that it is silvery or dark instead of 

 white or yellow, it crackles when manipulated and it collapses 

 promptly when pricked. 



Following the abundant connective tissue in cattle the emphy- 

 sema is liable to extend to the roots of the lungs, the mediasti- 

 num, the connective tissue at the entrance of the thorax, the 

 lower part of the neck, shoulders, sternal region, walls of the 

 chest and loins. It may even penetrate the diaphragm by the 

 side of the oesophagus to reach the peritoneum. 



Symptoms. These are less marked than in the horse. The 

 breathing is rapid, it may be panting after active exertion and 

 in some instances there is a double rise of the flank with a motion 

 of the entire trunk in expiration. The most conclusive evidence 

 is obtained in the drum-like resonance on percussion over the 

 affected part of the lung, mostly below and in front. The diag- 

 348 



