NOTES ON SHOEING OF HORSES. 21 . 



proportion of adhesive material than those of the 

 crust or sole. It is this pecuharity of structure 

 which gives to the frog its toughness and elasticity. 



As is the case with the sole, the outer covering of 

 the frog gradually at its own proper time, if left to 

 itself, shells off or disappears insensibly by friction 

 with the ground. 



A thoroughly healthy frog does not require to be 

 touched with the knife. A ragged frog is generally 

 more or less unhealthy ; such a frog may, perhaps, 

 be advantageously trimmed, because ragged parts, 

 if allowed to remain, harbour wet and dirt ; and 

 moreover may, in a carelessly managed stable, be 

 the means of concealing for a length of time the 

 existence of actual disease. 



Wet and dirt, aided by general neglect, are the 

 ordinary causes of disease of the fi:og. Too much 

 attention, therefore, cannot be given to keeping the 

 frog clean and dry. 



The sensitive and vascular frog lies immediately 

 above the outer and insensitive frog, and is protected 

 by it from external blows and injuries. Its office is 

 to secrete the insensible frog. 



25. The insensible frog, when duly preserved. Functions 



. I, . _,. . of the frog. 



performs three very important functions : First, it 

 acts as an elastic pad at the back of the foot, and, 

 receiving on itself much of the concussion which 

 ai'ises from the weight and action of the horse, 



