368 DISEASES OF THE HORSE'S FOOT 



If lameness is met with at all, then it is where we have 

 a foot that is in other respects unsound, with badly con- 

 tracted heels and upright ' stumpy ' hoof, or where side- 

 bones have occurred in a young animal, and have already 

 reached a large size before the horse is put to labour. In 

 this latter case, the added effects of concussion and the 

 evil influences of shoeing are sufficient to turn the scale. 

 Directly the animal, previously sound, is asked to work, 

 lameness is the result. 



It follows, therefore, that side-bone in the feet of young 

 animals is of far more serious import than when occurring 

 in older horses. In a nag animal they constitute a positive 

 unsoundness, and lameness in this case is more often than 

 not an accompanying symptom. 



Causes. — To commence with, we may remark that, 

 although met with sometimes in very early life, side-bones 

 are seldom, if ever, congenital, and that more often than 

 not they may be looked for in animals of three years old, 

 or older — seldom earlier. They appear, in fact, only when 

 the animal is shod and commences work. 



This at once suggests two of the principal factors in their 

 causation — namely, concussion and loss of normal function. 

 Directly the horse is put to work he has for a great part of 

 his time to travel upon roadways — either macadamized 

 roads or town sets — where everything is calculated to bring 

 concussion about. In addition to that he has the lateral 

 cartilage itself thrown largely out of action by shoeing. 

 We explained in Chapter III. (p. 66) that the chief function 

 of the cartilage was to take concussion received by the 

 plantar cushion and direct the greater part of it outwards 

 and backwards. Now, with the animal shod, the plantar 

 cushion does not itself, as normally it should, receive con- 

 cussion. By the shoeing the frog is lifted from the ground, 

 and the plantar cushion, together with the cartilage, taken 

 largely out of active work. In other words, the normal 

 outward and inward movements of the cartilage are enor- 

 mously reduced. 



It is fair, we think, to take it that the mere fact of the 



