144 CHAPTERS ON EVOLUTION. 



species of animals, in so far as the welfare of evolution-theories is con- 

 cerned, is not difficult to trace or account for. Taking for granted 

 the very reasonable and obvious admission that any theory of evolution 

 must rest upon the idea of the production of new species by the 

 modification of the old, it follows that in our examination of living 

 nature we should expect to find evidence of the connection between 

 the varied forms of life in existence. From the monad up to man, 

 the evolutionist postulates an unbroken series not, indeed, as many 

 suppose, in one straight undeviating line, but rather after the idea of 

 a great tree with countless branches, offshoots, and diverging twigs, 

 which, however, unite in their lower limits in a common stem. Now, 

 is it possible, when we look around at the varied forms of animal and 

 plant life, to trace this unbroken sequence, this continuity of structure, 

 and this connected relationship ? The common observation of nature, 

 not to speak of even an elementary acquaintance with popular 

 zoology, forbids the idea, and at once negatives the supposition. 

 The forms of life, animals and plants, fall into groups and divisions 

 of varying extent and different rank in the scale of creation. In 

 each large group we include a number of lesser divisions, the 

 members of which are united by certain common characters. But 

 even in the smallest of our classes or orders, the gaps betwixt the 

 included forms are many and wide; and Nature, as we observe her pro- 

 cesses, does not appear to supply the " missing links," in the existing 

 order of affairs at least. In that great sub-kingdom of the animal world 

 which zoologists have parcelled out as the Vertebrata, or the territory 

 wherein man and quadrupeds reign as the aristocrats, birds and 

 reptiles as the middle classes with their varied estates and ranks, and 

 frogs, toads, and fishes as the lower orders and substrata of verte- 

 brate society, the gaps existing between the various classes are very 

 patent and clear to the merest tyro in natural history. Not even the 

 proverbial old lady with a marked partiality to a belief in the mar- 

 vellous in natural history, or towards a literal interpretation of the 

 compound zoological character of certain wondrous beasts mentioned 

 . in ancient fables, could be brought to entertain seriously the idea 

 of the existence of an animal half-reptile, half-bird. Still less 

 easy is it for the popular mind to conceive the existence of a 

 creature midway as to structure between the bird and the quadruped. 

 Whilst certain small jokers a race happily becoming, as regards 

 scientific matters, well-nigh extinct might be perfectly safe in chal- 

 lenging zoologists at large to produce the " missing links " between 

 man and his nearest animal relations ; or to show on Lord Monboddo's 

 hypothesis, the various stages in the decline of man's caudal appendage, 

 upon the disappearance of which that witty savant is presumed to 

 have founded a large part of man's physical and moral supremacy. 

 Amongst lower forms of life the gaps are equally apparent, and the 



