THE SPINE. 165 



now proceed to that portion of the spine which forms the roof of the chest 

 and belly. It consists of twenty-three bones from the neck to the haunch • 

 . eighteen, called dorsal vertebra, composing the back ; and five lumbar ver- 

 tebrce, occupying the loins. On this part of the animal the wein-ht or 

 burden is laid, and there are two principal things to be considered, easiness 

 of carriage, and strength. If the back were composed of unyieldino- ma- 

 terials, if it resembled a bar of wood or iron, the jar or jolting, in 

 the rapid motion of the animal, could not possibly be endured. To avoid 

 this, as well as to assist in turning, the back is divided into numerous 

 bones ; and between each pair of bones, there is interposed a cartilaginous 

 substance, most highly elastic, which will yield and give way to eveTy jar, 

 not so much as to occasion insecurity between the bones, or to permit 

 considerable motion between any one pair; yet forming altogether an 

 aggregate mass of elasticity, so springy that the rider sits almost undis- 

 turbed, liowever high may be the action, or however rapid the pace. 



Strength is as important as ease ; therefore these bones are united to- 

 gether with peculiar firmness. The round head of one is exactly fitted 

 to the cup or cavity of that immediately before it ; and between them is placed 

 the elastic ligamentous substance we have just described, so strong, that in 

 endeavouring to separate the bones of the back, the bones will breal sooner 

 than this substance will give way. Beside this there are ligaments 

 running along the broad under surface of these bones ; ligam.ents1)etween 

 each of the transverse processes, or side projections of the bones ; and 

 ligaments between the spinous processes, or upright projections ; and a 

 continuation of the strong ligament of the neck running along the whole 

 course of the back and loins above these, lengthening and contracting, as 

 in the neck, with the motions of the animal, and forming a powerftd 

 bond of union between the bones. 



By these means the hunter will carry a heavy man without fatigue or 

 strain through a long chase ; and those shocks and jars are avoided which 

 would be annoying to the rider, and injurious and speedily fatal to the horse. 



These provisions, however, although adequate to common or even severe 

 exertion, will not protect the animal from the consequences of brutal usage; 

 and, therefore, if the horse be much overweighted, or violently exercised, 

 or too suddenly pulled upon his haunches, these ligaments are strained : — 

 inflammation follows ; — and the ligament becomes changed to bone, and the 

 joints of the back lose their springiness and ease of motion ; or rather in 

 point of fact cease to exist. On account of the too hard service required 

 from them, and especially before they have gained their full strength, 

 there are few old horses, who have not some of the bones of the back or 

 loins ancJiT/losed, united together by bony matter, and not by ligament. 

 When this exists to any considerable extent the horse is not pleasant to 

 ride ; he turns with difficulty in his stall ; — he is unwilling to lie down, or 

 when down to rise again ; — and he has a curious straddling action. Such 

 horses are said to be broken-backed, or chinked in the chine. 



Fracture of the bones of the back rarely occurs, on account of their 

 being so strongly united by ligaments, and defended by muscular substance. 

 If a fracture of these bones does happen, it is during the violent struggles 

 after the horse has been cast for an operation. 



The length of the back is an important consideration. A long-backed 

 horse Avill be easy in his paces, because the increased distance between the 

 fore and hind legs, which are the supports of the spine, will afford greater 

 room for the play of the joints of the back. A long spring has much more 

 play than a short one, and will better obviate concussion. A long-backed 

 horse is likewise formed for speed, for there is room for him to bring his 



