The distance apart, T, T, of the two commissures of the lips gives, very nearly, the distance from the superior border of the orbital arch to the base of the ear or the auditory meatus. In the state of rest, the outer limit of the separation of the nostrils does not exceed the width of the knee;[67] we frequently find the same distance intercepted above the nape by the tranquil ears. In the figure (Fig. 110) we have intentionally represented them directed in a different plane, in order to show that when the pinna is turned backward, it none the less preserves the contour of bracket form, more or less pronounced according to the breeding of the subject, and characterizing in repose the interior curves of the ear. [67] We remind our readers that the name 'knee' is given by veterinarians to the region occupied by the carpus. The extreme limit of the lips, M, N, but very slightly exceeds that of the nostrils; on many heads of harmonious proportions this distance is found to be the half of A, B. In order not to interrupt the course of the preceding exposition, we decided to withhold till afterwards some reflections which have been suggested to us by certain of the proportions which are there indicated. The proportions in question are important--we may even say that they are fundamental, for they have for object the relation which exists between the length of the head, the height of the body, and the length of the latter. We have already seen that, according to Bourgelat, the length of the head is contained two and a half times in the length of the body, from the point of the arm to the point of the buttock; and, also, two and a half times in the height measured from the apex of the withers to the ground (see p. 265). We saw afterwards that M. Duhousset, having adopted these proportions, pointed out, further, that the same dimension was again found equally to exist from the summit of the crupper to the ground--a height which Bourgelat considered as being of less extent. There results, then, from the latter proportions, which we have just recalled, this interesting fact: that they simplify very much, from the point of view of design, the placing in position of the horse, on the condition always that this latter be always viewed directly on one of its lateral aspects. [Illustration: FIG. 112.--HORSE OF WHICH THE LENGTH CONTAINS MORE THAN TWO AND A HALF TIMES THAT OF THE HEAD, AND OF WHICH THIS DIMENSION (A, B) EXCEEDS THE HEIGHT.] Indeed, in this case, if we except the neck and the head, the body, inasmuch as its height and its length are equal, may be inscribed in a square, of which one of the sides corresponds to the withers and to the summit of the crupper, two of the other sides to the point of the arm and to that of the buttock the fourth being represented by the ground. This is simple, but this simplicity even has its inconveniences.