THE FOOT IN HEALTH AND DISEASE 117 



in them, and it is rather remarkable that the trouble 

 should be mainly confined to animals required for heavy 

 draught purposes. The percentage of light horses with 

 side-bone is comparatively small, and when this state of 

 affairs does exist it is considered to be much more detri- 

 mental than in the case of a heavy draught horse, owing 

 to its greater hability to produce lameness. The writer 

 has, however, examined light horses with well-marked 

 side-bone, yet these showed no indication of lameness. As 

 a precautionary measure it is always expedient, apart 

 from legal responsibility, to look upon side-bone as 

 sufficient cause for the rejection of a horse in relation to 

 soundness. Old horses of the cart horse type have almost 

 always signs of this disease. 



There is a preliminary stage to calcification, viz. 

 induration, and the cartilages are often found in this 

 condition. It is customary amongst veterinary surgeons 

 to pass horses — heavy draught horses — with side bone 

 as practically sound, provided that the heels are strong 

 and free from contraction. Unquestionably there is a 

 predisposition to contraction of the heels in well-marked 

 instances of side-bone, probably due to decreased func- 

 tional power in this particular region. Side-bone is 

 regarded by horse breeders as hereditary, and horse- 

 breeding societies are not supposed to make use of sires 

 having their lateral cartilages thus transformed. The 

 question is whether this is a correct view to take. It is 

 impossible to answer the question with any degree of 

 certainty, though it is equally certain that it is better to 

 choose a sire without side-bone than one with it, and this 

 is equally applicable to the dam. Perhaps the reader 

 will say that very few foals of the cart horse type would 

 be born if this rule were followed, a statement which is 

 undeniable. Probably one of the chief factors in the 

 production of this trouble is concussion, and it affects 

 the fore feet almost exclusively. Sometimes only one 

 cartilage is imphcated, at other times the inner and the 



