Masterpieces of Science 



lower end of the fibula; so that the, apparently- 

 single, lower end of the shin-bone is really 

 made up of the coalesced ends of the tibia 

 and fibula, just as the, apparently single, lower 

 end of the fore-arm bone is composed of the 

 coalesced radius and ulna. 



The heel of the horse is the part commonly 

 known as the hock. The hinder cannon bone 

 answers to the middle metatarsal bone of the 

 human foot, the pastern, coronary, and coffin 

 bones, to the middle toe bones; the hind hoof 

 to the nail; as in the fore-foot. And, as in the 

 fore-foot, there are merely two splints to repre- 

 sent the second and the fourth toes. Sometimes 

 a rudiment of a fifth toe appears to be traceable. 



The teeth of a horse are not less peculiar 

 than its limbs. The living engine, like all others, 

 must be well stoked if it is to do its work; and 

 the horse, if it is to make good its wear and tear, 

 and to exert the enormous amount of force 

 required for its propulsion, must be well and 

 rapidly fed. To this end good cutting instru- 

 ments and powerful and lasting crushers are 

 needful. Accordingly, the twelve cutting teeth 

 of a horse are close-set and concentrated in the 

 fore-part of its mouth, like so many adzes or 

 chisels. The grinders or molars are large, and 

 have an extremely complicated structure, 

 being composed of a number of different 

 substances of unequal hardness. The con- 

 sequence of this is that they wear away at 

 different rates; and, hence, the surface of 

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