129 



That the chief cause, both predisposing and exciting, is to be 

 attributed to a morbid contraction of the foot, acting mainly 

 upon the posterior part, I think, is equally unquestionable. 



Persistent undue contraction of the quarters not only crowds 

 the secreting structures of the horny sole and frog, but involves 

 the sub-cutaneous tissues adjacent to the heels in the general 

 crush. 



Crowding of the secreting structures of the foot is no more 

 conducive to healthy exercise of function and healthy nutrition 

 than crowding in other spheres of observation, such as trees in 

 a garden, or plants in a bed. The Chinese custom of encasing 

 the feet of their female children in shoes of iron, has the same 

 effect- in kind upon the human foot as the hardened hoof and 

 its iron appendage has upon the foot of the horse. 



DIFFICULT TO MISUNDERSTAND. 



I should think the etiology and pathology of these affections 

 difficult to ////^understand, but lest they should not be, I will 

 glance at the chain of causes which connects faulty shoeing 

 with Grease, Canker and Thrush ; weakening the sole gener- 

 ally, and opening the heels leads to the falling of the first 

 anteriorly, and the closing in of the quarters posteriorly. The 

 two most important functions of the foot at first are partially, 

 and eventually, totally suspended by the injudicious use of the 

 paring-knife alone. Those usually removed portions should 

 be the solid points of resistance for the spring of the sole within 

 the foot, and the expansion of the quarters when the weight of 

 the animal descends during motion. 



THE MACHINERY IS OUT OF GEAR. 



The abnormal pressure created by the altered structure and 

 functions of the horny tissues, produces vascular excitement 

 and inflammation of the tissues subjected to the pressure, which 

 communicates itself by sympathy with, and to, adjacent and 

 subjacent tissues. All the secreting structures in, and 

 around the foot, are affected in a greater or less degree, de- 



