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We now come to the vascular or sensitive tissues within 

 the hoof, which are subject to so many diseases. 



Molded upon the entire surface of the coffin bone is a 

 thick villous, highly vascular and sensitive tissue, which is 

 commonly called the " sensitive foot," but also having several 

 distinct local names, according to the particular part it 

 covers. This tissue is nothing more than an expansion of 

 the dermis (or true skin), or it may be said to be a process 

 from the skin, somewhat altered in its structure to adapt it 

 to the secretion of horn ; it is analogous in many respects to 

 that part of the skin which produces the nails in the human 

 species. This tissue has the following local names : when it 

 surrounds the top of the hoof it is called the " coronary sub- 

 stance;" covering the coffin bone, the "sensitive laminoe;" 

 covering the sole, the "sensitive sole;" the frog, the "sensi- 

 tive frog." This vascular tissue has for its function the 

 secretion of horn ; for this purpose it is thickly studded with 

 secreting papillae, and forms as well as repairs the horny 

 wall and sole of the roof. According to Virchow each 

 papillae corresponds to one of the horny laminae. The sen- 

 sitive laminae, as it covers the coffin bone, is arranged in 500 

 or 600 folds side by side, for which reason it is called laminae. 

 These sensitive folds of the laminae fit into the horny laminae, 

 and form so many springs giving and reinforcing the elas- 

 ticity of the foot. This tissue, when constituting the sen- 

 sitive sole, averaging one eighth of an inch, is thinner over 

 the frog and thicker over the heels, and is even more vascular 

 than where it covers the coffin bone. It is closely connected 

 with the fibrous tissue of the sensitive laminae in front and 

 the covering of the heels and frog behind, and from it the 

 horny sole and frog are secreted. The manner in which the 

 wall of the foot is formed is the following : the outer layer 

 of horn, which is firm, hard, and dark of color, is secreted 

 and grows downward from the coronary substance ; it is also 

 thinner and tougher than what is secreted by the papillae of 

 the laminae. The inside layer of horn grows outwards from 



