282 DISEASES OF THE HORSE. 



regular play of every part of the apparatus will testify to the exist- 

 ence of that condition of orderly soundness and efficient activity 

 eloquently suggestive of the condition of vital integrity, which is 

 simply but comprehensively expressed by the terms health and 

 soundness. 



But let some change, though slight and obscure, occur among the 

 elements of the case; some invisible agency of evil intrude among 

 the harmonizing processes going forward; any disorder occur in the 

 relations of cooperating parts; anything appear to neutralize the 

 efficiency of vitalizing forces; any disability of a limb to accept and 

 to throw back upon its mate the portion of the weight which belongs 

 to it to sustain— present itself, whether as the effect of traumatic acci- 

 dents or otherwise; in short, let anything develop which tends to 

 defeat the purpose of nature in organizing the locomotive apparatus, 

 at once we are confronted by that which may be looked upon as a 

 cause of lameness. 



Not the least of the facts which it is important to remember is that 

 it is not sufficient to look for the manifestation of an existing discord- 

 ance in the action of the affected limb alone, but that it is shared by 

 the sound one, and must be searched for in that as well as the halting 

 member, if the hazard of an error is to be avoided. The mode of 

 action of the leg which is the seat of the lameness will vary greatly 

 from that which it exhibited when in a healthy condition, and the 

 sound leg will also offer important modifications in the same three 

 particulars before alluded to, to wit, that of resting on the ground, 

 that of its elevation and forward motion, and that of striking the 

 ground again when the full action of stepping is accomplished. 

 Inability in the lame leg to sustain weight will imply excessive exer- 

 tion by the sound one, and lack of facility or disposition to rest the 

 lame member on the ground will necessitate a longer continuance of 

 that action on the sound side. Changes in the act of elevating the 

 leg, or of carrying it forward, or in both, will present entirely opjio- 

 site conditions between the two. The lame member will be elevated 

 rapidly, moved carefully forward, and returned to the ground with 

 caution and hesitancy, and the contact with the earth will be effected 

 as lightly as possible, while the sound limb will rest longer on the 

 ground, move boldly and rapidly forward, and strike the ground 

 promptly and forcibly. All this is due to the fact that the sound 

 member carries more than its normal, healthy share of the weight of 

 the body, a share which may be in excess from 1 to 250 pounds, and 

 thus bring its burden to a figure varying from 251 to 500 pounds, all 

 depending upon the degree of the existing lameness, whether it is 

 simply a slight tenderness or soreness, or whether the trouble has 

 reached a stage which compels the patient to the awkwardness of 

 traveling on three legs. 



That all this is not mere theory, but rests on a foundation of fact 



