CHANGED CONDITIONS. 173 



slow paced and torpid, with a foot perfectly adapted 

 to such a region (its ground face being so extensive 

 and flat that it sinks but little, and the frog developed 

 to such a degree as to resemble a ploughshare in 

 form, which gives it a grip of the soft, slippery 

 ground), is but indifferently suited for travelling on 

 a hard, rugged surface. 



' In process of time, however, the small, concave hoof 

 expands and flattens, and the large flat one gradually be- 

 comes concentrated, hardened, and hollow, these changes 

 being designed to suit the altered physical conditions 

 in which the animals are placed.' (Prize Essay, 1870.) 



The above extract from Professor Fleming's essay 

 shows that the conversion of a soft hoof into a hard 

 one is simply a matter of time, and that the owner 

 of a soft-hoofed horse must not be discouraged if the 

 process should not be as rapid as he expected. 



There is yet another point to be considered. 

 Professor Fleming goes on the supposition that the 

 two horses possessed untouched hoofs ; and it is evi- 

 dent that if the hoofs had been mutilated by the 

 farrier, the process must take a still longer time. 

 Here again, owing to the variability of hoof-growth 

 in different animals, it is impossible to lay down any 

 definite law on the subject. 



Taking the average of growth, the entire hoof of 

 a shod horse is renewed annually. But when the 



