246 EXTINCT MONSTERS 
the organ of smell, give them ample means of becoming aware of 
the approach of enemies; while the length of their limbs, the 
angles different segments form with each other, and especially 
the combination of firmness, stability, and lightness in the reduc- 
tion of all the toes to a single one, upon which the whole weight 
of the body and all the muscular power are concentrated, give 
them speed and endurance surpassing that of almost any other 
animal.” At the same time that these changes were taking place 
(and in accordance with the “Law of Correlation”) certain 
important changes in the structure and mode of growth of the 
teeth were being developed, the consequence of which was that 
they were able to masticate and grind up their food much more 
perfectly, and thus, no doubt, to obtain therefrom more vital 
energy with which to supply their muscles and nerves for working 
their limbs more rapidly as they became fitted to attain higher 
speed. They gained a grinding tooth for each toe that they lost. 
Of these ancient horses it may well be said they “ran the race 
that was set before them” or, perhaps we might say, which they 
set before themselves; and the victory was to the quickest 
runners—those who could “beat the record” made by their 
predecessors! It is a wonderful story, this, of the evolution of 
that noble and useful animal to which man is so much attached ; 
and one cannot help sometimes wondering whether to some extent 
the will of an animal may not be an important factor in Evolution, 
although it is the fashion to ignore it, and to attribute organic 
changes to Natural Selection, or the “survival of the fittest.” 
Mind has a powerful influence over matter, and can we not 
1 Visitors to the Natural History Museum will do well to examine the 
admirable set of casts and actual bones of fossil horses in Gallery No. 1. 
Complete casts of Phenacodus and Hyracotherium are there exhibited. In the 
hall may be seen the skeleton of a man and of a horse side by side, in the same 
relative position, also casts of bones represented in Fig. 89. 
