THE FORE LEG Oil CANNON. 67 



bone : an appellation given to it, I imagine, from some sort of re- 

 semblance it bears, it being perforated, to the barrel of a cannon, 

 or else to a tube or pipe, which in Latin is canna, and from 

 which our words cannon and canon are said to have been derived. 

 The two small bones are very commonly called the splent or splint 

 bones ; either because they are the seats of splents or splints, or 

 from their own resemblance to splenters or splinters of wood, or of 

 other hard splitting substance. The cannon bone constitutes the 

 shaft of support of the leg : above it and upon it, with the inter- 

 position of the knee, stands the arm ; while its lower end rests 

 upon the pastern bone. The splint bones, pyramidal in shape, and 

 adherent to the sides of the cannon, taper downward into points, 

 or rather terminate in small tubercular knobs, which have no 

 resting-places — no articulation with any bone beneath them ; the 

 consequence of which is, that the whole of the weight they receive 

 in the support they give the body must have been directly trans- 

 mitted to the cannon bone, had they not been cemented to its 

 sides by a soft elastic substance, something of an intervening 

 nature between cartilage and ligament, which admits of their yield- 

 ing downward ; — " descending," as Professor Coleman's expression 

 used to be — every time pressure from above is imposed upon 

 them. And as the superincumbent weight, in accordance with 

 the laws of the centre of gravity, bears more upon the inner than 

 upon the outer sides of the limbs, so the inner splint bone is fur- 

 nished at the knee with an independent joint, i. e. one of the bones 

 of the knee-joint rests exclusively upon the head of the inner 

 bone ; which is not the case with the bone on the outer side, that 

 receiving but a part of the articulation of the bone of the knee 

 above it # . 



This yielding downward or descent of the splint bones on the 

 imposition of weight, and of the inner more than of the outer bone, 

 and the instantaneous recoil of them, or ascent, the moment the 

 active pressure has ceased, has long, by veterinarians, been re- 

 garded as one of many contrivances, operating, after the manner of 

 a spring in the limb, to save the animal machine from receiving 



* A reference to these parts in the skeleton will demonstrate what I have 

 said. 



