. The comparative anatomy of the domesticated animals. Veterinary anatomy. 810 THE APFABATUS OF THE a. CONSTITUENT ELEMENTS OF THE WALL. Horn-cells; 6, Horn- Pigmentary-corpusdes exist in the substance of the coloured horn, and are disposed singly, or in small masses, in the epithelial cells of the intertubular substance. The presence of these corpuscles has been denied, and the coloration has been attributed to a greater condensation, at certain points, of the epithelial elements. Fine pigment-granules are disseminated in the cells, but it is evident that beyond these there are at di
. The comparative anatomy of the domesticated animals. Veterinary anatomy. 810 THE APFABATUS OF THE a. CONSTITUENT ELEMENTS OF THE WALL. Horn-cells; 6, Horn- Pigmentary-corpusdes exist in the substance of the coloured horn, and are disposed singly, or in small masses, in the epithelial cells of the intertubular substance. The presence of these corpuscles has been denied, and the coloration has been attributed to a greater condensation, at certain points, of the epithelial elements. Fine pigment-granules are disseminated in the cells, but it is evident that beyond these there are at different points pigment-corpuscles; for, after treating a section of coloured horn with soda,- the epithelial elements are distended, become pale, and disappear, leaving, however, here and there, masses of black granulations. These pigmentary-corpuscles are absent in white horn. Development of the Hoof.—The hoof being a dependency of the epidermis, is developed like it: that is, by the incessant formation of cells in the layer that corresponds to the rete mucosum, at the expense of the plasma thrown out by the numerous vessels in the keratogenous membrane. The velvety tissue forms the sole and frog; the perioplic ring the periople, and the coronary cushion the wall. In these different parts, the epithelial cells multiply, and become flattened in layers parallel to the surface that secretes them, and in proportion as they recede from that surface; so that the wall grows from its fibre from the hoof of superior to its inferior border, and the other two parts Lrthe^veTticaf dif odi ^^ *^^ ^^^^ ^^^^ *^^^^ internal to their external face. tion of the cells. The villosities of the coronary cushion and the velvety tissue are the organs around which the epi- thelial lamellsB are grouped, and their presence determines the tubular structure of the horn; their function is completed by the exhalation of a particular fluid that maintains the flexibility of the hoof, and, probably, by the d
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectveterinaryanatomy
