338 DISEASES OF THE HOKSE. 



syringe, the milk or nutritive gruels selected for his sustenance until 

 the consolidation is sufficiently advanced to permit the ingestion of 

 feed of a more solid consistency. The callus will usually be suffi- 

 ciently hardened in two or three weeks to allow of a change of diet 

 to mashes of cut hay and scalded grain, until the removal of the 

 dressing restores the animal to its old habit of mastication. 



FRACTURES OF VERTEBRAE. 



These are not very common, but when they do occur the bones most 

 frequently injured are those of the back and loins. 



Causes. — The ordinary causes ot fracture are responsible here as 

 elsewhere, such as hea\^ blows on the spinal column, severe falls 

 while conveying heavy loads, and especially violent efforts in resist- 

 ing the process of casting. Although occurring more or less 

 fi'equently under the latter circumstances, the accident is not always 

 attributable to carelessness or error in the management. It may, of 

 course, sometimes result from such a cause as a badly prepared bed, 

 or the accidental presence of a hard body concealed in the straw, or 

 to a heaA-y fall when the movements of the patient have not been 

 sufficiently controlled by an effective apparatus and its skillful 

 adaptation, but it is quite as liable to be caused by the violent 

 resistance and tlie consequent powerful muscular contraction by the 

 frightened patient. The simf)le fact of the overarching of the 

 vertebral column, with excessive pressure against it from the in- 

 testinal mass, owing to the spasmodic action of the abdominal 

 muscles, may account for it, and so also may the struggles of the 

 animal to escape from the restraint of the hobbles while frantic 

 under the pain of an operation without anesthesia. In these cases 

 the fracture usually occurs in the body or the annular part, or both, 

 of the posterior dorsal or the anterior lumbar vertebra. ^Mien the 

 transverse processes of the last-named bones are injured, it is probably 

 in consequence of the heavy concussion incident to striking the 

 gi-ound when cast. The diagnosis of a fracture of the body of a 

 vei-tebra is not always easy, especially when quite recent, and more 

 especially when there is no accompanying displacement. 



Syniptoms. — There are certain peculiar signs accompanying the 

 occurrence of the accident while an operation is in progress which 

 should at once excite the suspicion of the surgeon. In the midst of 

 a violent struggle the patient becomes suddenly quiet ; the movement 

 of a sharp instrument, which at first excited his resistance, fails to 

 give rise to any further evidence of sensation; perhaps a general 

 trembling, lasting for a few minutes, will follow, succeeded by a cold, 

 profuse perspiration, particularly between the hind legs, and fre- 

 quently there will be micturition and defecation. Careful examina- 

 tion of the vertebral column may then detect a slight depression or 



