STRUCTURES OF THE BODY. 



between the stock raised in the arid plains of the Punjab and 

 Deccan, and those of swampy Lower Bengal. Hence, if, 

 when judging an animal about the history of which we know 

 nothing, and which does not appear to have undergone 

 enough work to test the soundness of his legs, we find that 

 he has weak, fiat hoofs, we shall not err, in the large 

 majority of cases, by concluding that his bone is of inferior 

 quality. I may add, as regards climate, that although dryness 

 is always a favourable condition for horses, the effect of 

 excessive heat apparently is to diminish the size of the bone 

 of the indigenous animals : a circumstance which may, to a 

 great extent, account for the fact that horses bred in tropical 

 climates, however hardy and wiry they may be, are very 

 rarely of a weight-carrying type, like those met with in 

 temperate countries. 



What is popularly called " want of bone " seriously 

 detracts from the usefulness of an animal, whatever its work 

 may be, as it implies deficiency of muscular development ; for 

 muscles, I may say, cannot act properly unless they have a 

 sufficient surface of bone on which to attach themselves. It 

 would, however, be more correct to state that we cannot 

 have large bones without large muscles ; for the size and 

 development of a bone is directly dependent on the condition 

 and state of activity of the muscles connected with it. This 

 follows from the fact that a bone, like all other parts of the 

 animal system, in order to be strong, requires a plentiful 

 supply of blood for its nourishment, the circulation being 

 quickened by exercise, which can alone be obtained by 

 muscular action. As pointed out by Professor Marey, in 

 cases of paralysis of a limb, the bones of the part become 

 wasted on account of the loss of function of the muscles. In 



