SPAVIN. 501 



view wtich is partly accurate and partly diagramatic), will afford 

 the rationale to these facts. 



Locomotion of the animal upon macadamized roads, or 

 upon any part of the surface of the earth, cannot be without 

 concussion — to resist the effects of which, the limbs are evi- 

 dently constructed upon the most perfect principles. Observe 

 the skeleton of the animal, — and more especially for our pur- 

 pose, the arrangement of the bones of the hind limbs. These 

 bones, when occupying their proper position, form with one 

 another four great angles, which angles will be more or less 

 acute according to the position of the bones in the living horse, 

 both when the animal is at rest, and also during the act of 

 locomotion. 



The first angle (beginning at the foot) is formed between 

 the bones of the foot, the pastern, and the cannon-bone a ; the 

 second, between the cannon-bone a and the tibia li — the joint 

 of the hock, in this instance, uniting the two mediately ; the 

 third angle is formed between the tibia Ti and the femur ; and 

 the fourth between the head of the femur and the pelvis, cer- 

 tain lateral processes of which hold the spinal column securely 

 in its natural position. . •' 



The angles at which these bones are placed, with regard to 

 one another, will to a certain extent constitute a safeguard 

 against those shocks and concussions which the animal will 

 experience when moving over the surface of the ground. A 

 second safeguard will be in the great number of soft tissues 

 which enter into the formation of the entire limb ; while a 

 third exists in the number of the bones of the hock, and in the 

 manner in which they are placed or secured one upon the other. 

 In spite of these beautiful and complex arrangements, however, 

 experience proves that the hock is extremely liable to suffer 

 from sprains and concussions, and that a very common result, 



