226 THE FORE LIMB. 



horn of the wall and sole is weak, it will not be able to 

 efficiently support the weight thrown on the leg, and the foot 

 will have a tendency to become flat. The feet of, for instance, 

 horses bred in Australia are far stronger than those produced 

 in England, owing to the climate being drier ; although both 

 are practically of the same blood. The fact that water 

 mechanically softens horn, does not explain why the hoofs of 

 horses in damp climates should be produced thinner than 

 those of animals in dry climates. We know from experience, 

 however, that moisture has a great influence in quickening 

 the growth of horn, as we may see in horses turned out on 

 marshy ground. Also, in those parts of India where the 

 yearly rain-fall, though large in quantity, is practically con- 

 fined to about four consecutive months, it is found that the 

 growth of the horses' feet during the "monsoons" is much 

 greater than it is in the dry weather. Hence, we may reason- 

 ably conclude that this stimulation in growth is one of length 

 of horn, and not one of increased horny material. The case, 

 I submit, is somewhat analogous to that of plants, which, 

 under the influence of an excess of moisture, spring up quickly, 

 with tissues full of water, but with little solid matter. The 

 great trouble with heavy cart-horses in England is from 

 the weakness of their hoofs, the horn of which, as a rule, is 

 neither thicker nor stronger than that of well-bred horses ; 

 although the strain which falls on it is much greater than that 

 which tries the tenacity of the horn of the feet of saddle 

 horses. Considerinof the orreater size of the muscles and 

 bones of the draught animal, we should expect that the horn 

 of his hoofs would be proportionately stronger than that of 

 the half-bred. The fact that it is not stronger, is a proof 

 that English cart-horses are deficient in one of the most im- 



