DEVELOPMENT OF MUSCLE 147 



Carpenter (" Human Physiology ") remarks that " the 

 frequently renewed exercise of muscles, by producing a 

 determination of blood towards them, occasions an increase 

 in the nutrition, so that a large amount of new tissue is 

 developed, and the muscles augment in size and vigour. 

 This is true, not only of the whole muscular system when 

 equally exercised, but also of any particular set of 

 muscles which is more used than another. Of the former, 

 we have an example in those who practise a system of 

 gymnastics adapted to call the various muscles alike into 

 play ; and of the latter, in the limbs of individuals who 

 follow any calling that habitually requires the exertion 

 of either pair to the partial exclusion of the other, as the 

 arms of the smith, or the legs of the opera-dancer. But 

 this increased nutrition cannot take place unless an 

 adequate supply of food be afforded ; and if the amount 

 of nutritive material be insufficient, the result will be a 

 progressive diminution in the size and power of the 

 muscles, which will manifest itself the more rapidly as 

 the amount of exertion, and consequently the degree of 

 ivasUy is greater. JSTor can it be effected if the exercise 

 be incessant, for it is during the intervals of repose that 

 the reparation of the muscular tissue occurs; and the 

 muscular system, like the nervous, may be worn out by 

 incessant use. The more violent the action, the longer 

 will be the period of subsequent repose required for the 

 reparation of the tissue." 



From this we see that, while giving the horse the 

 exercise necessary to develop those muscles which are 

 used in galloping, we should attend to his proper feeding ; 

 should afford him the rest indispensable for the repair of 



