64 EXAM IN A TION OF HORSES 



this line of greatest weight, — or in other words they 

 expand. 



Again, physiology teaches us that when a part 

 is deprived of functional activity by enforced rest it 

 loses in weight and bulk; therefore the front half of 

 the foot being deprived of function (expansion), grows 

 less rapidly than the heels, which, as we have seen, do 

 actually expand ; and as we know that growth of the 

 horny fibre of the hoof takes place from above down- 

 wards, therefore we have the heels, whose functions are 

 freely exercised, growing in height at a faster ratio than the 

 front half of the foot. It further follows that the deeper 

 the heels grow the higher does the frog become lifted 

 from the ground, a?id approximate to the level of the centre 

 or focus of weighty and therefore the more horizontal do 

 the rays become ; so that as the frog is lifted higher and 

 higher, the less and less weight has it to bear, it there- 

 fore melts away, and allows the heels to come together. 



It is thus we get high heels and contraction. Quod 

 erat demonstrandwn. 



