THE PROBLEM STATED. 5 



limbs respectively of all vertebrate animals ? How, on any other 

 hypothesis save that of evolution, and of the common origin of the 

 .animals in question, can we explain why the arm of man, the 

 wing of the bird, the horse's fore-limb, the dog's fore-leg, and the 

 whale's paddle, are constructed on a common plan ? Or, again, why 

 should the bodies and appendages of lobsters, insects, spiders, and 

 centipedes, be similarly identical in fundamental structure, unless on 

 the theory of their common origin? 



Again, from the region of Development, the evolutionist derives a 

 whole host of cogent reasons for the faith he entertains in the sound- 

 ness of his conclusions. All animals begin life under a similar guise 

 or, to come to actual details, as protoplasmic specks. In their earliest 

 stages, the germs of a man and of an animalcule are indistinguishable. 

 Furthermore, as human development proceeds along its lines, it 

 assumes its own and special phases only after passing through stages 

 which correspond more or less completely with permanent forms of 

 lower animals. At first each quadruped is thus fish-like, and after 

 successive developments leading it upwards through reptile and bird 

 phases, it attains the quadruped type. But, even as a quadruped, the 

 human organism itself declares its nobility of blood, only as a final 

 feature in its early history. Of all other animals, the same recital 

 holds good. Each animal comes to assume its own place as an 

 adult through stages of development which repeat, as in a moving 

 panorama, the phases of the lower life through which its ancestry 

 has passed. The development of the individual animal is thus the 

 brief and condensed recapitulation, often more or less obscured, of 

 the development of the race or species. If facts like these be not 

 admitted to prove the reality of evolution, then development as a 

 whole must present itself as a series of the most meaningless 

 paradoxes which it has been the fate of man to discover in the 

 universe around. 



Such are a few of the considerations to be fully illustrated in 

 succeeding chapters which suggest that evolution is a great truth 

 and a sober fact of living nature. Other topics of equal importance 

 such as the occurrence of rudimentary and useless organs in animals 

 and plants, the existence of "links" between distinct groups, the 

 results of degeneration, and other subjects will also be found fully 

 detailed in the following pages, which partake, indeed, of the cha- 

 racter of a continuous series of proofs of the truth of the evolution 

 theory. It requires, however, to be pointed out in the present 

 instance, that whilst the general truth of evolution is now admitted 

 by all competent biologists, there exists considerable diversity of 

 opinion regarding the exact factors to which the processes of modi- 

 fication are due. Thus the title of Mr. Darwin's classic work is 

 " The Origin of Species by Means of Natural Selection ; or, the 



