10 THE EVOLUTION THEORY 



cases, where the parts fitted, there resulted a creature capable not 

 only of life, but, if the juxtaposition was perfect, even of reproduction. 



This phantastic picture of creation seems to us mad enough, but 

 there slumbers in it, all unsuspected though it may have been by the 

 author, the true idea of selection, the idea that much that is unfit 

 certainly arises, but that only the fit endures. The mechanical 

 coming-to-be of the fit is the sound kernel in this wondersome 

 doctrine. 



The natural science of the ancients, in regard to life and its 

 forms, reached its climax in Aristotle (died 322 B. a). A true poly- 

 historian, his writings comprehended all the knowledge of his time, 

 but he also added much to it from his own observation. In his 

 writings Ave find many good observations on the structure and habits 

 of a number of organisms, and he also had the merit of being the 

 first to attempt a systematic grouping of animals. With true insight, 

 he grouped all the vertebrates together as Enaimata or animals with 

 blood, and classed all the rest together as Anaimata or bloodless 

 animals. That he denied to the latter group the possession of blood 

 is not to be wondered at, when we take into account the extremely 

 imperfect means of investigation available in his time, nor is it 

 surprising that he should have ranked this motley company, in 

 antithesis to the blood-possessing animals, as a unified and equivalent 

 group. Two thousand years later, Lamarck did exactly the same 

 thing, when he divided the animals into backboned and backboneless, 

 and we reckon this nowadays as a merit only in so far that he was 

 the first, after Aristotle, to re-express the solidarity of the classes of 

 animals which we now call vertebrates. 



Aristotle was, however, not a s}^stematic zoologist in our sense 

 of the term, as indeed was hardly possible, considering the very small 

 number of animal forms that were known in his time. In our day 

 we have before us descriptions of nearly 300.000 named species 

 wherefrom to construct our classification, while Aristotle knew hardly 

 more than 200. Of the whole world of microscopic animals he could, 

 of course, have no idea, any more than of the remains of prehistoric 

 animals, of which we now know about 40.000 named and adequately 

 described species. One would have thought that it would have 

 occurred to a quick-witted people like the Greeks to pause and ponder 

 when they found mussel-shells and marine snail-shells on the hills far 

 above the sea; but they explained these by the great flood in the 

 time of Deucalion and Pyrrha, and they did not observe that the 

 fossil molluscs were of different species from the similar animals 

 living in the sea in their own day. 



