78 CHAPTER 8. 



autumn to be occasionally exercised in deep (/round. 155. Hard condition 

 to be antecedent to fast work. 156. Of two hours' so-called exercise. 157. 

 Of exercisiny in clothing. 157ci. Exercise or work in bandages. 158. 

 Time for exercisiny horses. 159. Training of race horses. 



127. Need of exercise. 



As air is to the lungs or food to the stomach, so is exercise to the due 

 development of the muscles, tendons, ligaments, and respiratory organs. 



In the horse, on account of the active exertions which we require from 

 him, we wish to get the muscles as firm, the tendons and ligaments as 

 strong, and the respiratory organs as vigorous as possible. We therefore 

 give exercise, more or less severe according to the use for which the 

 particular horse may at the time be required. 



In the ox and sheep, and other animals which are used for food, we 

 wish to have the flesh less lirni and more tender j and therefore we give 

 little or no exercise. 



128. Musclee. 



Muscle is simply flesh. Anatomically considered, it is made up of 

 bundles of fibres laid parallel to each other. The tenacity or strength of 

 the fibres depends chiefly on the use to which they are subjected. When 

 disused, they become soft, flaccid, and incapable of sustaining any great 

 strain. 



Muscular development is a very important element in the strength of 

 a horse. Muscles under nervous influence possess a power of contraction. 

 By means of this power they act upon and control the tendons, and in 

 fact regulate the movements of the body. Hence in one sense muscles 

 are the real motive power in the animal frame ; but it must not be for- 

 gotten, that the muscles themselves are set in motion by the action of the 

 nervous system. Hence if a nerve is paralysed, the muscle to which it 

 goes, loses its power of contraction. 



Muscles are occasionally ruptured by an over-violent strain ; but injury 

 to them commonly consists in some of the fibres being tom across. The 

 blood-vessels, however, which ramify about the fibres, are more frequently 

 ruptured by any such strain than the fibres themselves. This result is 

 marked by extravasation of blood in the part under the skin. 



129. Tendons. 



Tendons are dense, firm, fibrous, almost inelastic organs. They are 

 attached at their upper extremities to the ends of muscles, and at their 

 lower extremities are generally inserted into the eminences of bones. 

 They possess no power of motion or contraction in themselves, but are 

 acted on by the muscles to which they are attached. Tendons arc found 

 wherever strength combined with lightness is required, and where muscle 

 on account of its bulk would be inadmissible. 



Tendons, like muscles, strengthen and develop, when properly and 



