84 THE POPULAR SCIENCE MONTHLY. 



at some length, and has illustrated by a diagram. The evolution 

 of the horse of historical times, and of the present day from the 

 orohippus of the Eocene period, as exhibited to the eye by Mr. 

 Wallace's diagram, is as interesting a presentation of a physical 

 pedigree as can well be conceived. We see, as it were, the progress 

 of Nature's work ; the transformation from several toes to one toe, 

 which was, in reality, the operation of thousands of years, is visi- 

 ble as a connected continuous process from beginning to end. But 

 what the diagram does not, and can not, put in evidence is this — 

 namely, the marvelous beauty of the horse in his ultimate con- 

 dition. So far as any conclusions can be drawn from the diagram, 

 the top and the bottom of the page stand upon an equal footing ; 

 there would seem to be no reason why orohippus should not have 

 been derived from equus by expansion, as easily as equus has 

 been derived from orohippus by contraction. When, however, 

 we look, not at the equus of science, but at the horse of the hunt- 

 ing-field or the race-course, or at our own stable friend, who has 

 carried us safely for hundreds of miles, we perceive that, somehow 

 or other, we have, in these modern days, an animal of the most 

 perfect kind with regard to speed, beauty, and mechanical perfec- 

 tion. We feel convinced that it would be in every way a mistake 

 that he should develop toes and become orohippus ; we are sure 

 that orohippus has rightly been improved off the face of the earth 

 in order to make room for equus. All this is, in the best sense of 

 the phrase, in accordance with the principle of the survival of the 

 fittest ; but I confess that I find it difficult to realize the transfor- 

 mation of orohippus into equus upon the pure and simple notion 

 of advantageous variations in the struggle for life ; for, in truth, 

 if the question be one of mere survival, it is difficult to say, when 

 the earth was inhabited by wild creatures, in what manner the 

 possession of one toe instead of three or four should give equus 

 any advantage over orohippus. One can quite understand that a 

 jury of Newmarket jockeys would decide that equus was fittest to 

 survive ; but in the absence of human judgment the conclusion is 

 not so easy to reach. At all events, it seems more probable that 

 the transformation was originally ideally contained in the concep- 

 tion of this class of creature, and that equus may be regarded as 

 bearing to orohippus something of the same kind of relation as is 

 borne by a frog to a tadpole, or by a moth to a caterpillar. 



May it not well be that predetermined transformation has as 

 real a place in the genesis of species as it certainly has in that of 

 individual creatures ? Nothing, perhaps, strikes most minds as 

 more surprising than insect and reptile transformation. That a 

 crawling animal should, by a complicated process, involving a 

 condition of motionless helplessness, be ultimately transformed 

 into a creature of active life spent in flying through the air, or 



