410 REVIEW—BRIDGEWATER TREATISES, No. 4. 
in a straight line, end to end, the shock of alighting would be 
conveyed through a solid column, and the bones of the foot or 
the joints would suffer from the concussion. When the rider is 
thrown forwards on his hands, and more certainly when he is 
pitched on his shoulder, the collar-bone is broken, because, in 
man, the bone forms a link of connexion between the shoulder 
and the trunk so as to receive the whole shock; and the same 
would happen in the horse, the stag, and all quadrupeds of great 
strength and swiftness, were not the scapula sustained by mus¬ 
cles, and not by bone, and did not the bones recoil and fold up. 
“The horse-jockey runs his hand down the horse’s neck in a 
knowing way, and says, ^ this horse has got a heavy shoulder; he 
is a slow horse.’ He is right, but he does not understand the 
matter: it is not possible that the shoulder can be too much 
loaded with muscle, for muscle is the source of motion, and be¬ 
stows power. What the jockey feels, and forms his judgment 
on, is the abrupt transition from the neck to the shoulder, which, 
in a horse for the turf, ought to be a smooth undulating surface. 
This abruptness or prominence of the shoulder is a consequence 
of the upright position of the scapula; the sloping and light 
shoulder results from its obliquity. An upright shoulder is a 
mark of a stumbling horse : it does not revolve easily to throw 
forward the foot. Much of the strength, if not the freedom and 
rapidity of motion, of a limb will depend on the angle at which 
the bones lie to each other; for this mainly affects the insertion, 
and, consequently, the power of the muscles. W'e know, and 
may every moment feel, that when the arm is extended, we pos¬ 
sess little power in bending it; but as we bend it the power is 
increased, which is owing to the change in the direction of the 
■force acting upon the bone, or, in other words, because the ten¬ 
don becomes more perpendicular to the lever. 
A Scapula. 
B Tuberosity of the 
Humerus. 
C Olecranon, or Pro¬ 
jection of the 
Ulna. 
P Radius. 
E Humerus, or Arm- 
Boue. 
