234 DISEASES OF EONE. 



similar bones in the ox and sheep, we might reasonably conclude 

 that it would be an advantage to the horse if the lower two-thirds 

 of his splint bones were non-existent. Agreeably to principles 

 already discussed, we find that the closeness of connection between 

 a splint bone and its cannon bone decreases from the knee (or hock) 

 downwards. In fact, although the upper end of a splint bone is 

 closely united to the head of its cannon bone, its lower end is 

 generally free. 



The foregoing observations tend, I think, to show that partial 

 union of a splint bone with its cannon bone is often a perfectly 

 natural result of increasing years, and cannot, in such a case, be 

 regarded as a disease. 



In the course of the evolution of the horse, the second and 

 fourth metacarpal bones, instead of occupying a more or less for- 

 ward position, as they once did, have gradually taken up their 

 positions at the back of their respective cannon bones; the three 

 bones thus forming a groove for the suspensory ligament, which 

 was once a muscle. This arrangement of the splint bones is a 

 serious predisposing cause of lameness in horses ; because a splint, 

 on account of the consequent bony enlargement, would be apt to 

 give rise to painful pressure on this ligament. Hence the advisa- 

 bility, when practicable, of removing the cause of lameness, namely, 

 the offending portion of bone. 



The distance of the lower end of a splint bone from its fetlock 

 is a very variable quantity; in fact, the splint bone, on rare occa- 

 sions, comes down to the level of the fetlock, and is furnished with 

 a pastern and hoof. In " Points of the Horse," I have given a 

 photograph I took of an example of this form of atavism. 

 Although the average curtailment of length of the splint bones 

 meets the requirements of horses at liberty in the open, it is not 

 sufficient for the abnormal amount of concussion which the animal's 

 legs have to endure when trotting on a hard road, or carrying a 

 rider at the gallop, even on soft and elastic turf. Hence, abnormally 

 long splint bones, especially if their respective lower ends are im- 

 usually thick, are often predisposing causes of lameness. 



I think that the foregoing considerations warrant us in assuming 

 that the frequency of splints (union of the splint bones with their 

 large metacarpal or metatarsal bone) is increasing, and their 

 gravity diminishing in an equal ratio. Age exhibits a similar 

 tendency. Abroad, I have often heard it remarked that well-bred 

 English horses are far more liable to splints than foreign breeds 

 which live in a semi-wild state. Artificial conditions and selection 

 in breeding, when favourably applied, tend to hasten the slow 

 course of evolution. 



The heavier a horse's body is, compared to the strength of the 



