154 



DISEASES OF 



to a one-toed animal, there is constant deviation from 

 any one absolute, special, and exact form and shape. 

 The foot of the horse is in a condition similar to any 

 structure that has been developed in comparatively re- 

 cent times where change readily takes place and 

 where the normal balance is readily upset. A glance 

 at the following diagram will show the changes in the 

 foot of the horse. Fig. 47. 



Tig. 47. Showing feet of ancestors of Horse. 



Again, the uses to which horses have been put by 

 civilized man have necessitated changes of structure 

 in many parts of the body, notably in that of the foot. 

 For instance, travel on macadamized roads requires 

 a foot structurally much stronger than on soft ground. 

 In other words, the foot that will suffer no disorder 

 when used for travel on soft, dirt roads, may be irrem- 

 ediably damaged by travel for only a short time on the 

 macadamized roads ,of to-day. It has been frequently 

 argued by writers on the foot that horses in a state of 

 nature rarely have foot disorders, and that therefore 

 shoeing is the cause of most of the ills that affect the 



