The different constituent elements which we have just been discussing give elasticity to the foot. To finish the examination of the parts contained in the hoof, we will add that among them is also found what is called the fleshy _envelope_, or _flesh_ of the foot. We divide the latter into three regions: the podophyllous tissue, striated or laminated flesh which is spread out over the anterior surface of the third phalanx; the pad, or the hardened skin which corresponds to the upper border of the hoof, and forms a prominence above the podophyllous tissue; and the villous flesh, or velvety tissue which covers the plantar surface of the third phalanx and the plantar cushion. These three tissues form as a whole the keratogenic membrane--that is to say, that which produces horny tissue, and consequently regenerates the hoof. It is this latter that we now proceed to study. When we examine its anterior surface or the opposite one, the hoof of the horse has the shape of a truncated cone with the base below and the summit cut off obliquely downwards and backwards (Fig. 97). Viewed on one of its lateral aspects, it may be compared to a truncated cylinder placed on the surface of the section (Fig. 98). We particularly call attention to this latter comparison, for it singularly aids us in making a representation of the foot of the horse when viewed laterally. Notwithstanding that the hoof forms apparently a homogeneous whole, it consists of three parts, which may be separated from one another by maceration. The indication of such disunion, artificially produced, may seem useless. It is not so, however, for this division of the hoof will permit us to carry out the study of the latter in a clearer, and consequently a more satisfactory, way. The three parts in question are the _wall_, or _crust_, the _sole_, and the _frog_. The _wall_ is that portion of the hoof which we see when the foot rests on the ground. It is a plate of horn which, applied to the anterior and lateral surfaces of the foot, diminishes in height as it approaches the posterior part of the region. Posteriorly and at each side the wall is folded on itself, and is then directed forwards to terminate in a point, after having enclosed the frog, which we will soon study. [Illustration: FIG. 97.--LEFT ANTERIOR FOOT OF THE HORSE: ANTERIOR ASPECT. 1, Outer side; 2, inner side.]