58 THEORY OF EXERCISE. 



within healthy limits excites the nervous system to give the 

 signal for movement. Somewhat similar to appetite for food 

 and thirst for water, there seems to be a craving for exercise 

 in the animal organisation, especially during youth, at which 

 time exercise is particularly required for development. As 

 horses in the open, even when fed on corn, take the larger 

 portion of their daily exercise at a walk, we may safely follow 

 the same plan with stabled horses. Although exercising a 

 horse chiefly at faster paces and only once during the day 

 economises time and paid labour, it does not produce such a 

 good effect on the health and strength of an animal as giving 

 the bulk of the exercise at a walk, and taking him out twice 

 daily, which as a rule will be as often as can be usually 

 managed. I think that a sound horse should not get less 

 than three hours' exercise daily, and that it would be better 

 to give him four hours of it, divided into two and a half hours 

 in the morning, and an hour and a half in the afternoon. 



The speed of a horse can be largely affected by habit. 

 Thus, a hack or trapper which is accustomed to be walked 

 and trotted in a slovenly slow style, loses his speed at these 

 paces to a greater or less extent, in the same manner that a 

 horse practised in a riding school becomes slow at a gallop in 

 the open. A fast hunter which passes for the first time into 

 the hands of a heavy weight, will after a season or two, 

 considerably improve in his weight-carrying powers, but with 

 a proportionate loss of speed. In seeking to gain speed, the 

 distance over which the animal is extended should never be 

 so long as to cause fatigue ; for in that case, the rate of the 

 " spin," and especially the rate of its concluding portion, will 

 be comparatively slow, and an injurious impression will be 

 made on the horse's speed, to say nothing of the depressing 

 effect which the consequent fatigue will have on the nervous 

 system. 



Disuse has a well-marked depressing effect on speed, 



