DISEASES OF THE WITHEES. 775 



5th. Purulent infection, i. e., consecutive with the caries of the 

 vertebrae and with the phlebitis of the veins of the region. 



6th. Purulent pleurisy, resulting from the passage of the pus 

 into the thoracic cavity through the intercostal muscles. 



7th. Exhaustion, in consequence of the uncompensated loss 

 of substance by the abundant continued suppuration, and its ac- 

 companying severe and persistent fever. 



Fistulous withers is always a serious disease, not only because 

 of its progressive tendency, but also because, however intelligent 

 and proper may be the treatment it receives, it can never be relied 

 on to prevent the spreading of the necrosis, and assure a healthy 

 cicatrization. The degrees of severity nevertheless vary, accord- 

 ing to circumstances. It is less serious when the necrosis is on 

 the median line, and the prognosis is stUl more favorable when it 

 is on the posterior part of the region. "When situated forward it 

 seems more tenacious, and the danger of its extending to the 

 neck is greater. But it is principally when its seat is in the an- 

 terior part of the vrithers that the prognosis becomes alarming, as 

 there the spinous processes are less prominent, the muscles thick- 

 er and more complicated in their arrangements, and the cartilage 

 of the scapula nearer, all these being conditions which render the 

 discharge of the pus more dif&cult and the purulent infiltrations 

 more likely to take place, and where also counter-openings are 

 made with more dififtculty, and indeed become almost impossible 

 if the purulent accumulations are situated on the inside of the 

 scapiala or its cartilage of prolongation. 



It may be said, in fact, that the most important factor in the 

 prognosis of this disease is the distance which separates the apex 

 of the spinous processes of the vertebrae from the superior border 

 of the cartilage of the scapula ; the chances of recovery being in 

 the ratio of the distance between those two points. It is thus 

 that it becomes less grave in weU-bred animals, with elevated pro- 

 jecting withers, than in low draught horses in which that region 

 is depressed and thick, and the projection of the dorsal processes 

 often replaced by a deep groove, bound on each side by the pro- 

 jection of the muscles and of the border of the scapular cartilage. 

 The disease is also of less gravity in young animals, except when 

 they are under the influence of distemper. 



The treatment required in fistulous withers includes two prin- 

 cipal indications : 1st. To facilitate the escape of the pus and 



