A stabled horse keeps his health and strength best when the duration of his exercise is about equal to that which his ancestors experienced in the open, and when the degree of the exercise is proportionate to the amount of energy received from the food. We should here bear in mind that corn given to horses which are at grass, acts on them as a stimulant to take exercise. In fact, the assimilation of potential energy 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, especially with horses that have passed their youth, which is essentially the period of speed. Hence we often find that if fast racehorses are put out of work for a considerable time, they generally suffer a far greater loss of speed than could be accounted for by increased age. The poor form shown by the once famous Signorina on her return to the turf, after having proved a failure at the stud, is a good case in point. Experience proves that speed in either man or beast can be maintained after youth has passed, only by constant practice. In this connection, the names of Reindeer, Herald, Tommy Tittlemouse, Regal and Gamecock will occur to racing men; those of Flora Temple and Highflier to trotting men; and those of Jackson the American Deer, Choppy Warburton, Williamson, Hindie, and Harry Kelly to lovers of pedes-trianism and rowing. Flora Temple did her fastest mile when she was seventeen years old, Williamson was running in Sheffield Handicaps up to the age of forty-five, and Jackson was able to beat fifty-five minutes for ten miles when he was over fifty; but all these horses and men kept continually on the track during their respective careers. Therefore, if we wish to preserve a horse's speed, we should on no account throw him out of work, unless we were forced to do so, as for instance by his becoming unsound.

Dr. Vaughan Harley (Lancet, 1884, Vol. i., p. 1199) points out that less muscular work can be done at 9 a.m. than at 11 a.m.; that muscle power rises from the former hour to the latter; and that there is a notable fall in it at 4 p.m. I am inclined to think that the same rule holds good with horses. The daily decline in strength appears to be due to the accumulation of waste nitrogenous matter in the blood, and consequently fatigue is then produced with abnormal readiness. It is evident that the best time for giving strong daily exercise is at an hour when the bodily strength is at its highest degree.

The chief lesson, as far as stable management is concerned, which we learn from the foregoing considerations, is that the more severe the exercise or work, the greater is the necessity for keeping the excretory organs in healthy action, and for supplying the animal with pure air and plenty of good drinking water. The skin is the only one of these organs which we can safely stimulate artificially for a prolonged period, and then only by grooming and by a moderate amount of clothing.