8 (JX THK NAVICULAR DISEASK. 



arising from the frog- receiving the repetition of vio- 

 lence from the hard ground in an equal proportion 

 with the heels of the shoe. I therefore advise that 

 the frog be brought as near to the ground as possi- 

 ble, except by so much of the heels of the shoe as 

 may be necessary to break the force of concussion, 

 and yet allow the frog to receive some part of the 

 pressure, in a secondary manner, before the foot 

 quits the ground. 

 Oncoftiieusts I belicve, however, I am now at issue with the 

 frog— defends Profcssor, wlicu I statc my conviction that one of 



the synovial or . . , . i • i i p i 



lining mem- its uscs IS to scrvc as a cushiou or elastic bed tor the 



brane of tlie . , . . 



tendon. navicular jomt to rest upon, not merely for the pur- 



pose of protecting the insensible flexor tendon, as 

 Mr. Freeman states, but especially for the protec- 

 tion of the line delicate synovial membrane lining 

 the navicular joint, a web as exquisitely sensible, 

 when inflamed, as the outer coat or conjunctiva of 

 the human eye. 



There is another important function that the frog 

 is intended by nature to perform, which, in the hands 

 of art, it is seldom allowed to do, — which is, to act 

 as an elastic prop of support when the animal is in 

 action as well as stationary. It had its bold pro- 

 minent figure for the purpose of afl'ording a larger 

 basis to receive the weight, as by increasing the 

 ground surface of the foot it relieves the flexor ten- 

 don of a part of the burthen. Every unshod colt's 

 foot (foals excepted), free from thrush, clearly evinces 



