FKACTURES. 177 



upon the bone fractured. There is first an effusion of blood 

 takes place around the fractured ends between the perios- 

 teum and the bone. After a certain time this sanguineous 

 effusion is removed by absorption. An exudation of lymph 

 takes place, the reparative material being deposited between 

 the fractured ends of the bone, and is known as the callus. 

 The callus increases in hardness from day to day, until it 

 finally becomes as hard as any bone, and then the process 

 of reparation is completed. It is wonderfid how quickly 

 the above described changes will take place, particularly in 

 the dog. The process of repair takes place very rapidly 

 indeed if the fractured bone be a small one; it is, hoAV- 

 ever, somewhat tedious if the fractured bone be a large 

 one ; but if the fractured ends are placed and retained in 

 proper position, and the animal not too old, union is only 

 a question of time. 



Dorsal Spines. — ^The dorsal spines are liable to fracture. 

 A fracture here is generally due to an ill-fitting saddle. 

 Often in old horses anchylosis of the dorsal vertebrae exists 

 and is manifested by a pecuhar stiffness of the back, 

 well shown when the animal turns around. The back 

 descends to a certain extent. (On casting such a horse 

 fracture of the bodies of the vertebrcC is very likely to 

 occur, and will generally produce complete or partial 

 l^aralysis. If the fractured parts separate and press upon 

 the cord, the animal will be unable to rise, and complete 

 paralysis may occur. On pricking the animal with a 

 pin he shows no sign of having felt it. The hind 

 legs can be moved about in any direction, or placed 

 in any position without the slightest resistance being 

 offered by the patient. The fieces, etc., may be passed 

 involuntarily). The symptoms of fracture of the lumbar 

 vertebrae are about the same. 



Treatment. — If the case is diagnosed to be fracture of one 



12 



