4()8 REVIEW—BRIDGEWATER TREATISES. No. 4. 
pus, forming what by a sort of license is called the knee, is also 
newly modelled ; but the metacarpal bones and phalanges of the 
fingers are totally changed, and can hardly be recognized. When 
we look in front, instead of the four metacarpal bones we see 
one strong bone, the cannon bone; and posterior to this we find 
two lesser bones, called splint bones. The heads of these lesser 
bones enter into the knee joint; but at their lower ends they di¬ 
minish gradually, and they are held by an elastic ligamentous 
attachment to the sides of the cannon bone. 
I have some hesitation in admitting the correctness of the 
opinion of veterinary surgeons on this curious piece of mechanism. 
They imagine that these moveable splint bones, by playing up 
and down as the foot is alternately raised and pressed to the 
ground, bestow elasticity and prevent concussion. The fact cer¬ 
tainly is, that by over-action this part becomes inflamed, and the 
extremities preternaturally joined by bone to the greater metacar¬ 
pal or cannon bone; and that this, which is called a splint, is a 
cause of lameness. 
I suspect, rather, that in the perfect state of the joint, these 
lesser metacarpal bones act as a spring to throw out the foot when 
it is raised and the knee joint bent. If we admit that it is the 
quickness in the extension of this joint on which the rate of mo¬ 
tion must principally depend, it will not escape observation, that, 
in the bent position of the knee, the extensor tendons have very 
little power, from their running so near to the centre of motion 
in the joint, and that, in fact, they require some additional 
means to aid the extension of the leg. 
