THE TYPES AND CLASSES OF HORSES 



85 



or constricted hoof head. When the foot is raised the under 

 side should present a slight arch with a well developed 

 frog, wide at its base, which just rests on the ground when 

 the foot drops to the surface. A flat foot lacks the desired 

 arch and is not easily trimmed by the smith ; it also bears 

 too much concussion at the low set heel. The frog consists 

 of elastic, fibrous material and serves as an important 

 buffer and protection against injury to sensitive tissues 

 and nerves within the foot and especially just above the 

 frog. A great weight rests on the bones and membranes 

 within the hoof, and in a measure these are protected by 

 a slight arch of sole and well developed frog. For this 

 reason the blacksmith should never disturb the frog, ex- 



Fig. 42. — "Usually the horse will raise the foot without resistance." 



