302 
LECTURES ON HORSES. 
or safety of the form, and but little its strength : every projecting 
part has already its prop of support, and the intermediate parts, 
unless the form be one of extraordinary length, require none. Thus 
it is with the animal body. Its oblong formation demanded four 
supporters, two before and two behind: three would not have 
given it the stability and power of resistance it at present pos- 
sesses ; and again, to have added two legs more, would have 
nothing increased the security of the standing posture, and but 
little the powers of support, while loco-motion must by such an 
addition necessarily have become more or less complicated and 
impeded. 
It is seldom that the horse, while at rest, employs all his legs 
in maintaining the standing posture : commonly, one of the hind 
limbs will be found flexed — in a state of relaxation and repose, 
propping up the body passively only — while the other three re- 
main extended : in this position, changing the flexed hind-leg from 
time to time, a horse will not only take his rest, but will sleep ; no 
attention of the will or vigil being required to keep him upon his 
legs. Some horses never lie down — never appear to require re- 
cumbent repose. 
Another reason why Nature has given four legs to the quad- 
ruped, is, that he may be enabled in progression to steadily poise 
himself upon three of them, while the fourth is in motion off the 
ground. Not merely in the walk and trot, but even in the gallop, 
is the action of the legs, both in leaving and coming to the ground, 
alternate ; and though two or three, or even all four feet may be 
in the air at the same instant of time, they never leave the ground 
nor alight upon it again simultaneously : by such a mode of action 
the purposes of progression are excellently served on the one hand, 
while on the other, the machine experiences no such concussion as 
it would have done had there existed but three legs, or had two of 
them come to the ground simultaneously, as is the case sometimes 
in gallopping and leaping. 
One advantage more accruing from the gift of four over a less 
number of legs is, that, having two before and two behind, the 
quadruped is enabled to use either pair as weapons of defence : the 
horse can rear or kick against his enemy; indeed, the hind legs 
may be said to be the horse’s especial armaments against his foes. 
Some animals use their fore-legs in the way we do our arms, 
having claws instead of hoofs, which serve them after the manner 
of fingers : this they could not do were they not provided with 
two hind-legs, upon which they have the power of sitting or sup- 
porting themselves while their fore-limbs are otherwise employed. 
The POSITION, as well as the number of the limbs of the 
quadruped, evinces excellent contrivance of design. Not only 
