THE FORERUNNERS OF THE HORSE 281 



three sorts of material of different degrees of hard- 

 ness — enamel, dentine, and cement, which through 

 differential wear always present a roughened grind- 

 ing surface. 



" During the early life of the horse the tooth is 

 continuously growing, and, in spite of the fact that 

 it must constantly move outward to compensate for 

 wear, the root penetrates deeper and deeper within 

 the jaw until fully formed. The outward move- 

 ment still continuing, the tooth now gradually 

 shortens until in extreme old age it is practically 

 consumed. The total length of the tooth is nicely 

 calculated to meet the needs of a full measure of 

 life." 



That all these marvellous changes and adapta- 

 tions are not due to any mere " blind struggle for 

 existence" or "survival of the fittest," but that 

 they were directly designed and controlled by an 

 Omniscient and Omnipotent Creator, is the settled 

 and final opinion of the author of this volume. 



