96 CHAPTERS ON EVOLUTION. 



is sufficient for our present purpose to point out that in the structure 

 of the foot alone we discern the evidence for evolution as clearly 

 as in the entire organisation of the animal. An increase of speed, 

 and obvious advantage over its enemies, would be gained by the 

 horse, as its toes grew " small by degrees and beautifully less; " and the 

 single-toed race has thus practically come to the front in the world 

 of to-day, as the plain and favourable result of the work of degrada- 

 tion amongst its digits. It may likewise be mentioned, that the 

 conclusions of evolution and geology are strengthened by the evidence 

 of teratology, or the science of abnormalities. Occasionally horses 

 are born with several toes ; this fact being explicable only on the 

 idea of " reversion " to a multiple-toed ancestry. 



Two bony shreds or rudiments thus lay the foundation of a 

 grave conclusion regarding the horse and its manner of develop, 

 ment, and exemplify the adage that great and unlooked-for results 

 sometimes spring from beginnings of apparently the most trifling 

 kind. The "splint-bones" form, in fact, a clue which, when rightly 

 pursued, leads not merely to a knowledge of the evolution of the 

 horse, but to an understanding of the entire scheme of nature. 

 For if evolution is the law of the horse's history, it must logically 

 follow that it represents the scheme of nature throughout: 

 since the uniformity of nature, in which we are bound to believe, 

 and to which we are bound to appeal, would utterly negative 

 the idea that evolution should hold good for the horse, and 

 be inapplicable to any other living thing. Because the missing 

 links are not so completely supplied to us in other cases as in 

 the horse, we are not on that account entitled to assume that the 

 theory of development is invalid. We may not see an oak tree 

 grow inch by inch, but we are as positive as our mental nature will 

 admit, that the oak was once an acorn, and that there has been a 

 progressive growth and increase which might not be apparent to 

 us were we to watch the tree for weeks together. Applying this 

 reasoning to the case before us, it would be as illogical to deny 

 that the order of nature was that of development, as to insist that 

 the oak was created as it stands. The extent of human knowledge, 

 and the duration of human existence, are together inadequate to 

 enable us to discern the progress of this world's order after the 

 fashion whereby, from a lofty elevation, we may trace every winding 

 of a stream. But the probabilities of the case are as overwhelmingly 

 for progressive development, as the direct evidence at hand exem- 

 plified by the horse's pedigree tells against special and independent 

 creation having been the way of developmental law in the making 

 of the world and its living things. 



