306 DISEASES OF THE HORSE, 
without showing hesitancy or betraying pain, and when it is raised 
from the ground in order to transfer the weight to its mate it will 
perform the act in such manner that when it is again placed upon 
the ground to rest it will be with a firm tread, indicative of its ability 
to receive again the burden to be thrown back upon it. In planting 
it upon the ground or raising it again for the forward movement 
while in action, and again replanting it upon the earth, each move- 
ment will be the same for each leg and for each biped, whether the 
act is that of walking or trotting, or even of galloping. In short, 
the regular play of every part of the apparatus will testify to the 
existence 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 accident or 
otherwise; in short, let anything develop which tends to defeat the 
‘ purpose of nature in organizing the locomotive apparatus and we 
are confronted at once 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 oppo- 
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 
