22 PRACTICAL HORSESHOEING. 



dency to break off in flakes on the ground face when the 

 fibres have attained a certain length ; the wall, on the 

 contrary, continues to grow in length to an indefinite ex- 

 tent, and, unless kept within reasonable dimensions by 

 continual wear or the instruments of the farrier, would 

 in time acquire an extraordinary distortion. The horn 

 of the sole, for this reason, is less dense and resisting than 

 that of the wall, and is designed more to support weight 

 than to sustain wear. 



The " Horny Frog " is an exact reduplication of that 

 within the hoof, described as the sensitive or fatty frog. 

 It is triangular, or rather pyramidal in shape, and is situ- 

 ated at the back part of the hoof within the bars ; with 

 its point or apex extending forward to the centre of the 

 sole, and its base or thickest portion filling up the wide 

 space left between the inflexions of the wall. In the mid- 

 dle of the posterior part is a cleft, which in the healthy 

 state should not be deep, but rather shallow and sound 

 on its surface. 



In structure, this body is also fibrous, the fibres pass- 

 ing in the same direction as those of the other portions 

 of the hoof; but, instead of being quite rectilinear like 

 them, they are wavy or flexuous in their course, and pre- 

 sent some microscopical peculiarities which, though inter- 

 esting to the comparative anatomist, need not be alluded 

 to here. The fibres are finer than those of the sole and 

 wall, and are composed of cells arranged in the same man- 

 ner as elsewhere in the hoof; they are formed by the 

 villi which thickly stud the face of the membrane covering 

 the sensitive frog. 



The substance of the horny frog is eminently elastic, 

 and corresponds in the closest manner to the dense, elas- 

 tic, epidemic pads on the soles of the feet of such animals 

 as the camel, elephant, lion, bear, dog, cat, etc., and which 

 are evidently designed for contact with the ground, the 



