LAMENESS : ITS CAUSES AND TEEATMENT. 305 



Our first consideration should be the physiology of normal or 

 healthy locomotion, that thence we may the more easily reach our 

 conclusions touching lameness, or that which is abnormal, and by 

 this process we ought to succeed in obtaining a clew to the solution 

 of the first problem, to wit, in which'leg is the seat of the lameness ? 



A word of definition is here necessary, in order to render that 

 which follows more easily intelligible. In veterinary nomenclature 

 each two of the legs, as referred to in pairs, is denominated a biped. 

 Of the four points occupied by the feet of the animal while standing 

 at rest, forming a square, the two fore legs are known as the anterior 

 biped ; the two hinder, the posterior ; the two on one side, the lateral ; 

 and one of either the front or hind biped with the opposite leg of 

 the hind or front biped will form the diagonal biped. 



Considering, as it is proper to do, that in a condition of health 

 each separate biped and each individual leg is required to perform 

 an equal and uniform function and to carry an even or equal por- 

 tion of the weight of the body, it will be readily appreciated that 

 the result of this distribution Avill be a regular, evenly balanced, 

 and smooth displacement of the body thus supported by the four 

 legs, and that therefore, according to the -rapidity of the motion in 

 different gaits, each single leg will be required at certain succes- 

 sive moments to bear the weight which had rested upon its congener 

 while it was itself in the air, in the act of moving; or, again, two 

 different legs of a biped may be called upon to bear the weight of 

 the two legs of the opposite biped while also in the air in the act 

 of moving. 



To simplify the matter by an illustration, the weight of an animal 

 may be placed at 1,000 pounds, of which each leg, in a normal and 

 healthy condition, supports while at, rest 250 pounds. When one of 

 the fore legs is in action, or in the air, and carrying no weight, its 

 250 pounds share of the weight will be thrown upon its congener, or 

 partner, to sustain. If the two legs of a biped are both in action and 

 raised from the ground, their congeners, still resting in inaction, will 

 carry the total weight of the other two, or 500 pounds. And as the 

 succession of movements continues, and the change from one leg to 

 another or from one biped to another, as may be required by the 

 gait, proceeds, there will result a smooth, even, and equal balancing 

 of active movements, shifting the weight from one leg or one biped 

 to another, with symmetrical precision, and we shall be presented 

 with an interesting example of the play of vital machanics in a 

 healthy organization. 



Much may be learned from the accurate study of the action of a 

 single leg. Normally, its movements will be without variation or 

 failure. When at rest it will easily sustain the weight assigned to it 

 36444°— 16 ^20 



