76 FROM THE GREEKS TO DARWIN 



fostered the abiogenetic myth, that not only 

 smaller but larger animals, such as frogs, snakes, 

 and eels, are produced spontaneously from the 

 mud. Some of these and many other of his mis- 

 taken teachings were not wholly outlived until 

 the nineteenth century; yet we may not allow 

 them to detract from our general admiration of 

 his great genius. His failures in descriptive sci- 

 ence were chiefly in statements where he departed 

 from his own principle of verification and relied 

 upon the scientific hearsay of his day. 



The main bases of his ideas upon descent were 

 evidently drawn from his own observations upon 

 the gradations between marine plants and the 

 lower and higher forms of marine animals. He 

 was the first to conceive of a genetic series, and 

 his conception of a single chain of evolution from 

 the polyps to man was never fully replaced until 

 the beginning of the nineteenth century. It ap- 

 peared over and over again in different guises. 



Aristotle's Interpretation of Nature 



In all his philosophy and interpretation of Na- 

 ture, Aristotle was guided partly by his precon- 

 ceived opinions derived from Anaxagoras, Plato 

 and Socrates, and partly by convictions derived 

 from his own observations upon the wonderful 

 order and perfection of the universe. His 'per- 



