Experiments and their Verification 203 



unfolding of the fore leg the momentum of weight is directed in a 

 more vertical line. 



The angle at C is open toward the direction of motion, while the 

 angle at D opens in an opposite manner and away from it. Therefore 

 it is evident that forward extension is much more natural for the hind 

 leg than it is for the fore leg. While weight on the hind foot may 

 lower the elevation of action, it easily increases extension ; but in order 

 to increase extension in the fore legs we must not have too great a 

 flexion of knee or closing of angle B D F, but rather a sufficient ele- 

 vation of the knee D, together with a gradual unfolding or opening 

 of the angle at D, so that extension may be more easily accomplished. 



Reference is again made to Fig. 20, which gave the resultant ele- 

 vation of the foot due to high action and a sudden unfolding of knee 

 flexion in the curve A C, and the resultant greater extension due to a 

 lower action and a more gradual unfolding of knee flexion in the 

 curve A B. 



The direct effect of toe-weight is in throwing forward the foot at 

 the last part of the unfolding of fore legs, thereby increasing its ex- 

 tension. Mere weight of the front shoe induces greater flexion and 

 somewhat greater elevation of knee. Much depends on the trotter's 

 natural action in front, whether it be rapid or sweeping; and, again, 

 much depends on the action of the hind legs and their direct influence 

 on the fore. When a horse is naturally low gaited in front and has the 

 additional vicious attitude of hind feet pointing forward, the problem 

 of interference and of consequent balance is indeed a very hard one to 

 solve. 



While we cannot always separate the extremities in order to avoid 

 interference and with safety to the animal, the work should not, if 

 possible, confine itself to an effort for mere extension in front, but also 

 for more backward action behind. And, furthermore, an increased 

 elevation of hind action will also have its telling effect on the low 

 action in front. This inability of "getting away" in front is one of the 

 hardest problems of training and shoeing. Toe-weights will be ef- 

 fective to a degree, but the fault will be more or less of a bar to great 

 speed. Very often this fault is due to an unequal extension of feet, and 



