370 DISEASES OF THE HORSE'S FOOT 



saying that, some several years ago, the Council of the 

 Royal College of Veterinary Surgeons, at the request of the 

 Royal Commission on Horse Breeding, drew up a list of 

 those diseases ' which by heredity rendered stallions so 

 affected unfit as breeding sires,' and that in that list was 

 included side-bone. 



Side-bones, therefore, are hereditary. We think, how- 

 ever, the statement needs qualifying. It is in this way: 

 s'de-bones occur only at a certain, usually well-defined, time 

 after birth, and we might say are never congenital. They 

 occur only after the animal has been put to work, and are 

 more or less plainly due to mechanical causes — namely, the 

 ill effects of shoeing and concussion. The cause of their 

 appearance, in short, is more plainly extrinsic than intrinsic, 

 and side-bone in the horse is, as Professor McGill puts it, 

 about as much due to heredity as is corn on the human foot. 



Between these two opinions — that they are plainly 

 hereditary, and that they just as plainly are not — it is well 

 to strike a middle course. They are, we will say, heredi- 

 tary in this way : So long as a cart animal is bred, to put it 

 vulgarly, ' top-heavy ' (that is, with a body out of reason- 

 able proportion to the feet that have it to support), so long 

 will the foot be subjected to a greater concussion, and so 

 long will side-bones in such animals commence to make 

 their appearance at about middle life. 



In addition to the causes we have now mentioned, side- 

 bones are often the result of other diseases of the foot. 

 They thus occur as a sequel to sub-horny quittor, to sup- 

 purating corn, to complicated quarter sand-crack, or to the 

 inflammation of the parts occasioned by a prick. They also 

 arise in many instances from the effect of a prick or injury 

 to the coronet. Among the latter we may mention treads 

 from other animals, and treads inflicted by the animal him- 

 self with the calkin of an opposite shoe, or the repeated in- 

 jury occasioned by the shafts being carelessly allowed to 

 drop on to the foot. In severe cases of laminitis, too, the 

 cartilages are nearly always affected. In this instance the 

 inflammatory phenomena in the os pedis no doubt give rise 



