In considering the antiquity and history of the pacing horse, it seems to be necessary that we should have a clear perception of the mechanism of the gait from which he takes his distinctive name and the relation which that mechanism bears to other gaits or means of progression. In the study of this mechanism we learn the combination by which we unlock the mystery that has puzzled so many breeders of the past and present generations. Some have maintained that the pace is a combination of the trot and the gallop, while a smaller number have maintained that the fast trot was a combination of the pace and the gallop. It is quite evident, as I will be able to show, that neither of these parties has ever given any careful attention and study to the mechanism of the different gaits. The most simple and least complicated method of illustrating this mechanism of movement is furnished in the human means of progression. At the walk, a man steps off with his left foot and the heel of that foot strikes the ground before the toe of the right foot leaves it. Then the right foot advances and strikes the ground before the toe of the left foot leaves it. This is the natural “heel and toe” walk, and the speed may be increased by quickening the step and extending the stride, so far as physical conformation will permit. Still greater speed becomes a succession of bounds, the propelling foot leaving the ground before the advanced foot strikes it. This is running, the highest rate of speed attainable, and in every revolution, for a space, the whole body is in the air. In the action of the horse, with four legs, we find greater complication, which I will try to make clear. [Illustration: STAR POINTER. By Brown Hal, strictly pacing bred, record 1:59¼, 1897.] First, all horses walk, all horses pace or trot, and all horses gallop. The walk is easily analyzed, for it is slow and the movement of each limb can be followed by the eye. Each foot makes its own stroke upon the ground, and we count one, two, three, four in the revolution. Second, at the gallop, which is a succession of leaps, each limb, as shown by the instantaneous photograph, performs its own function, whether in rising from the ground, flying through the air, or in striking the ground again. There is harmony in all, but there is no unity in any two or more of them, and when they strike the ground again you hear the impacts, one, two, three, four, in a cluster. The conventional drawing of the running horse in action is impossible in nature, and a wretched caricature of the action as it is. As in the walk, so in the run, we count four impacts in the revolution.