L.AMENESS IN THE HIND LEG 227 



marked abduction at the time flexion occurs and in singular 

 instances the spasmodic contraction is so violent that the subject 

 falls to the ground as a result of the peculiar flexion of the leg. 

 In severe cases of "scratches" or chemical irritation of the 

 extremity, the legs are abnormally flexed in a manner which 

 simulates spring-halt, but because of the evident injury of the 

 parts this is not likely to confuse. Since all facts concerning 

 etiological agencies are surrounded with so much obscurity, clas- 

 sification does not lend any particular assistance in the consid- 

 eration of this ailment. 



Prog-nosis. — One cannot intelligently give a prognosis in 

 these cases if forecast is expected to state the exact course fol- 

 lowing treatment. However, in a general way, cases of recent 

 affection are thought more favorable than are those of long stand- 

 ing or in old animals where myositis and other muscular and 

 fascial affections exist owing to years of hard service. 



Treatment. — No known line of medicinal treatment is of 

 service, nor is any particular surgical operation to be considered 

 dependable for obtaining relief. Operations of almost every con- 

 ceivable nature have been tried with the hope of securing recov- 

 ery in spring-halt but under no condition can the practitioner 

 as yet be reasonably certain of effecting permanent relief in any 

 case. Treatment is, therefore, entirely empirical. 



Neurectomies have been performed and recoveries follo\\ing 

 were attributed thereto; fascial divisions in the crural region 

 have been done \^•ith good results and this manner of treatment 

 has its favorers. Advocates of tenotomies, likewise, are to be 

 found. Consequently, one may summarize thus : Spring-halt is 

 a disease of unknown origin — the exact cause has not been deter- 

 mined ; therefore, all treatment is, in a way, experimental. The 

 recommendation of any given procedure in handling cases must 

 then be a matter of opinion based either upon practical experi- 

 ence or knowledge of the experiences of others. Divisions of the 

 lateral digital extensor (peroneus) below the tarsus near its 

 point of insertion to the extensor of the digit is recommended 

 here because it is followed by a percentage of recoveries that is 

 as large as in any other method of treatment and the operation 



