CAUSES OF SADDLE-GALLS. 493 



affecting the occiput and the shoulder, counted 200 abscesses, from 

 the size of peas to that of a child's head. 



In severe injuries, like bruising of the skin and soft parts and 

 crushing of the spinous processes, diffused suppuration and lymph- 

 angitis are liable to ensue as complications, sometimes spreading 

 in the subcutis, and not infrequently also under the fascia. Necrosis 

 of the ligamentum nucha?, of the superior spinous processes, and 

 even of the deeper portions of the vertebra? may occur, and in ex- 

 ceptional cases necrosis of the ribs and of the shoulder-blade is seen. 



The above conditions must not be confounded with certain forms 

 of eczema, which are particularly apt to attack riding horses in regions 

 where there is much chalk dust. They affect the back, especially 

 behind the saddle-bed, but the extent of surface involved, the trifling 

 amount of swelling, and the thick scurf formed sufficiently 

 differentiate them. 



In a case described by Moller, pus formation had extended along 

 the fascia of the back as far as the pelvis, producing necrosis, and 

 also invaded the under surface of the longissimus dorsi, separating 

 the latter to a great extent from the ribs. Several ribs afterwards 

 became necrotic. Pus also appeared under the serratus anticus 

 major muscle. 



The prognosis depends on various factors. It is modified by — 



(1) The position of the swelling. The cutaneous is more hopeful 

 than the subcutaneous, especially if situated in the withers. 



(2) The duration of the swelling. The longer swelling has existed, 

 and the harder and more resistant it appears, the further has in- 

 filtration proceeded, and the more tardy will be resolution. Fistulous 

 withers of long standing is usually difficult of cure. 



(3) Cellulitis or lymphangitis adds to the gravity of the case. 

 The condition is of little gravity provided it remain aseptic ; the 

 occurrence of suppuration renders it serious, and doubly so if the 

 withers be the part involved. 



(4) In prognosing fistulous withers, particular note must be 

 taken of the degree of swelling and pain, and the amount of pus. 

 Swelling indicates extension of suppuration, if the discharge takes 

 place only on pressure from without, or during movements of the 

 animal. Intense pain points to injury of the superior spinous 

 processes. 



Causes. Certain horses suffer more than others, depending on 

 greater vulnerability of the skin, or on the presence of cicatrices 

 or scabs, or on peculiarities in form interfering with the fitting of 

 the saddle. Amongst these may be included abnormally high, low, 



