674 
LECTURES ON HORSES. 
situated upon the arm — in the hind extremity upon the thigh ; 
there being, as I before observed, no muscle or flesh, but tendon or 
sinew alone, below the knee and hock ; and these muscles are in- 
serted into the uppermost part of the leg, as close as possible 
to the centre of motion — the knee or the hock. Considering the 
length of the lever from either of these parts to the extremity of the 
hoof, it will at once appear to what a great disadvantage these 
muscles are acting ; when we come, however, to reflect, that the 
tendons could not have proceeded in the straight or direct line to 
the foot, on account of the infraction upon the form of the limb, 
and that by the present admirable arrangement, though power 
be lost, velocity of movement is gained, and gained in a manner 
to compensate even for that loss of power, we shall discover that 
an all- wise hand has in the construction of these parts not only 
overcome every difficulty, but at once accomplished every desira- 
ble object. For every half inch of contraction of the muscle, and 
corresponding half inch of space through which the leg revolves at 
the knee, the hoof at the extremity of the lever will move through 
a space equal in extent to as many feet, and the velocity of mo- 
tion being augmented in increasing proportion, it is evident that 
the force with which the foot strikes the ground must be greater 
even than if the muscles had been prolonged and attached to the 
foot itself. The increased weight of the horse-shoe at the very 
extremity of this lever will, when once set in motion, by adding to 
the momentum, like the weight upon the fly-wheel, augment still 
more this force ; though, of course, it will require greater exertion 
in the muscles, and so tend to tire the animal all the sooner. 
Short cannons, in reference to muscular action, are, therefore, pre- 
ferable to long ones, because their leverage is less, and because 
with long arms there is greater length and strength of muscle ; 
though it will be seen, from what has been said, that, in a mecha- 
nical point of view, they are not calculated to move with the same 
degree of velocity as long ones*. 
The muscles of the back, loins, and haunches, are remarkable for 
their size and power, and for the important parts they perform 
in progression. It has been before observed, that, for strength, the 
loins should be “ broad and rounded, the haunches fleshy, and the 
thighs let down to the hockst all which amounts to nothing more 
than saying, that the muscles constituting these parts should be 
large and powerful, it being quite impossible that a horse of slender 
muscularity in these — the most important of all — parts, in propor- 
tion, can either “ go,” or “ maintain the pace” as a hunter or racer ; 
* See what has been said about long and short arms and cannons in the 
description of the bones. 
t In Lecture I. 
