FUNCTIONS OF THE HOOF. 631 



The support afforded by the horny frog and plantar 

 cushion to the flexor tendons is not without its counter- 

 part in other regions of the body. We find cushions of 

 fat, for example, placed in various situations to act as a 

 pad, and particularly in maintaining the structures sur- 

 rounding joints in close approximation to these, espe- 

 cially in the anterior and posterior extremities ; but there 

 the enveloping muscles play the part that ground pressure 

 does on the frog. 



It may be noted that the wall or crust of the fore 

 foot is thickest at the front part, or toe, and gradually 

 diminishes in substance, as it does in depth, towards the 

 heels, the inside quarter and heel being the thinnest and 

 straightest, while the outside quarter is stronger, wider, 

 and more circular. The hind foot, on the contrary, is 

 strongest and widest towards the quarters and heels, and 

 is deeper there than the fore one; the frog is also 

 smaller, and the sole more concave. 



In the unshod fore foot, a large portion of the plantar 

 surface comes into contact with the ground, even when 

 this is in a hard condition. If we place a fresh hoof that 

 has never been shod — I mean one that has not been 

 trimmed and dressed by the farrier, and that belonged to 

 an animal with no hereditary defect in this respect — on 

 a table, we will find that the crust, bars, and a consider- 

 able portion of the posterior part of the frog are on the 

 same plane, and must have sustained wear together. The 

 outer surface of the crust looks shining, tough, and solid ; 

 the sole is wonderfully thick, and the horn beneath the 

 flakes, if there are any, is moist, flexible, and easily cut ; 

 while the frog, if it be a fore foot, extends well towards the 



