GEOWTH OF THE HOOF. 719 



we come to heavy draught labour, the idea appears still more 

 preposterous; for we find that many of our cart horses actually 

 wear through a greater thickness of iron, than there is horn 

 secreted; so that, were we to endeavour to harden their feet 

 by using them unshod, we should have to wait until the horn 

 of their feet had become harder than iron, before our object would 

 be attained ! Again, I may ask, would shoes have been generally 

 adojDted, had not experience taught horse owners the imperative 

 necessity for their employment under modern and civilised 

 requirements ? 



Young horses require to be shod, or t'heir shoes removed, 

 oftener than older animals ; because the horn of their feet grows 

 faster. A three or four year old should generally have his shoes 

 taken off every three weeks ; though an aged horse may go 

 a week longer. 



Growth of the Hoof. 



The hoof grows about 4 inches in the year. Usually, the yearly 

 growth at the heels is about J inch more than at the toes; but 

 there are exceptions. 



Mechanism of the Horse's Foot. 



THE FOOT AS A LEVER.— I may 'explain to those of my 

 readers who are unacquainted with anatomical mechanics, that 

 the movements of the limbs are due to the action of muscles on 

 bones. 



A muscle (which is the lean part of meat) has the power 

 of contracting in length on being stimulated by its nerves. 

 Muscles are attached to bones, as a rule, by tendons, which are 

 hard and inelastic continuiations of their respective muscles. 



If we regard the muscle which bends the foot and aids in 

 raising it from the ground, we shall find that it lies at the back 

 of the forearm ; that it is attached at its upper end to the bones 

 near the elbow, and at its lower end by a tendon (the flexor 

 perforaris, see Fig. 6) which runs down the back of the leg, at 

 and below the knee ; passes over the back of the fetlock ; goes 

 down the back of the pastern ; and is finally attached to the base 

 of the pedal (coffin) bone. This tendon forms one of the 

 two well-known " back tendons." When the horse is stand- 

 ing at rest, both the tendon and its muscle are " on the stretch," by 

 reason of tlie back of the fetlock pressing against the tendon. 

 On the signal being given from the brain, the nerves of this 

 muscle stimulate it to contract, and, on its becoming shorter, the 

 pastern and fetlock joints are bent and the heel raised. If we look 



