CHAP. III.] ASCERTAINED ! HOW BROUGHT OX. 479 



at times, though that be no greater than an effort 

 to relieve nature by a motion. The very great 

 number of joints in the bach-bone, added to its 

 horizontal position, render it more liable to sprain, 

 perhaps, than any other joint connecting longer 

 bones ; and this is the reason that the short-bone 

 joints of the foot are so liable to give way at appa- 

 rently trivial concussions. 



Cause. — Mostly affecting draught cattle of the 

 heavy kind, and principally incident to cities and 

 towns, where dray and cart-horses are obliged to 

 turn short upon slippery stones, we may ascribe 

 this disorder to what is called a wrench, or twist in 

 the human practice. The steady pull, unattended 

 by a turn, is not likely to occasion hurt of the back, 

 be it never so hollow originally ; because the effort 

 that is made to pull a great weight causes the joints 

 to press straight against each other, every capsule 

 being then filled with its next corresponding con- 

 vex bone. 



Symptoms. — A kind of separate motion for the 

 hind quarter, compared to the fore one, of which the 

 exact perceptible division is the seat of the injury. 

 Sometimes it appears as far back as the 4th lumbar- 

 spine, but when farther forward than the 15th, (at 

 O. 24, on the frontispiece,) it affects the respiration, 

 and with it other vital functions, and the animal 

 suffers in his general health. It may be muscular 

 or ligamentary, or compounded of both, in which 

 cases the parts adapt themselves to the derange- 

 ment that has taken place, by thickening their sub- 



