ACCIDENTS DUE TO EESTEAINT. 77 



bestowed on all the details of the work of casting. The very 

 peculiar circimistances under which these spinal fractures some- 

 times take place, baffling calculation, and occurring when least 

 expected or prepared for, illustrate the responsibility which the 

 veterinarian assumes, and the culpability with which he would 

 become chargeable by undertaking the work without due caution 

 and preparation, or without notifying the owner of the animal of 

 all the hazards and difficulties attending the case in all its steps 

 and stages. As wUl be seen when we come to the consideration 

 of this special lesion in the chapter on fractures, the symptoms 

 which accompany this accident are distinguished, as to one feat- 

 ure, by the suddenness of their appearance, which takes place at 

 the moment of the infliction of the injury or immediately after. 

 But the most important of the characteristics of the case is the 

 grave fact that the fracture is almost always of the comminuted 

 kind. This is held to be due to the excessively powerful mus- 

 cular contraction, resulting in the over-arching of the vertebral 

 column suhultaneously with pressure from the abdominal organs, 

 caused by the sudden extension of the anterior and posterior 

 bipeds, bound together with hobbles, the violence of the struggle 

 so powerfully pressing the vertebrae together as to result in the 

 yielding of their spongy structure; and the crushing or grinding 

 of the bone is the consequence. 



This theory of the production of fractures of this character 

 has been adopted by the majority of European veterinarians, es- 

 pecially by those of France, where it is understood as "Bouley's 

 Classical Theory." In 1889, however, another theory was pro- 

 pounded and defended by Mr. Moussel, of Alfort, differing en- 

 tirely from that of Bouley, in which he claims that the kiad of 

 fracture in question is not caused by an over flexion of the spine, 

 but, on the contrary, is the effect of an excessive extension! result- 

 iag from greater contraction of the Uio-spinaHs muscle. 



According to Dickerhoft, " three factors are active in the cau- 

 sation of these fractures. In the first place, the animal must have 

 some object as & point cF appui for one hind leg ; that point must 

 be connected with either one of the other extremities or directly 

 with the trunk. * * * Secondly, the horse must make his vertebral 

 column teuse by the contraction of the spinal extensor muscles. 

 * * * Thirdly, the horse must, simultaneously with the extension 

 of the hind leg' and that of the vertebral column, draw its pelvis 



