64 EXAMINATION 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, and approximate to the level of the centre 
or focus of weight, 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 aliows the heels to come together. 
It is thus we get higi. heels and contraction. Quod 
erat demonstrandum., \ 
\ 
\ . 
