DISEASES OF THE HOKSE. 275 



danger of incurring injuries which for their repair may demand the 

 best skill of the veterinary practitioner. And this is true not alone of 

 casualties which belong- to the class of external and traumatic cases, 

 but includes as well those of a kind perhaps more numerous, which 

 may result in lesions of internal parts, frequently the most serious and 

 obscure of all in their nature and effects. 



The horse is too important a factor in the practical details of human 

 life and fills too large a place in the business and pleasure of the world 

 to justify any indifference to his needs and physical comfort or neglect 

 in respect to the preservation of his peculiar powers for usefulness. 

 In entering somewhat largely, therefore, upon a review of the subject, 

 and treating in detail of the causes, the s^'mptoms, the progress, the 

 treatment, the results, and the consequences of lameness in the horse, 

 we are performing a duty which needs no v/ord of apology or justifi- 

 cation. The subject explains and justifies itself, and is its own vindi- 

 cation and illustration, if any are needed. 



The function of locomotion is performed by the action of two prin- 

 cipal systems of organs, known in anatomical and phj^siological termi- 

 nology as passive and active., the muscles performing the active and the 

 ho7ies the 2y<-issive portion of the movement. The necessary connection 

 between the cooperating parts of the organism is effected b}^ means 

 of a vital contact by which the muscle is attached to ttie bone at cer- 

 tain determinate points on the surface of the latter. These points of 

 attachment appear sometimes as an eminence, sometimes a depression, 

 sometimes a border or an angle, or again as a mere roughness,.but each 

 perfectly fulfilling its purpose; while the necessary motion is provided 

 for by the formation of the ends of the long bones into the requisite 

 articulations, joints, or hinges. Ever}^ motion is the product of the 

 contraction of one or more of the muscles, which, as it acts upon the 

 bonj' levers, gives rise to a movement of extension or flexion, abduc- 

 tion or adduction, rotation or circumduction. The movement of 

 abduction is that which passes from and that of adduction that which 

 passes toward the median line, or the center of the body. The move- 

 ments of flexion and extension are too well understood to need defin- 

 ing. It is the combination and rapid alternations of these movements 

 which produce the different postures and various gaits of the living 

 animal, and it is their interruption and derangement, from whatsoever 

 cause, which constitutes the pathological condition of lameness. 



A concise examination of the general anatom}^ of these organs, how- 

 ever, must precede the consideration of the pathological questions per- 

 taining to the subject. A statement, such as we have just given, con- 

 taining only the briefest hint of matters which, though not necessarily 

 in their ultimate scientific minutiae, must be clearly comprehended in 

 order to acquire a symmetrical and satisfactory^ view of the tlieme as a 

 practical collation of facts to be remembered, analyzed, applied, and 

 utilized. 



