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66 AMONG THE GREEKS. 



HeracHtus. The essence of this principle, that 

 evervthinsr was in a state of movement, and noth- 

 ing had reached a state of rest, underlies the later 

 doctrine of the gradually increasing perfection of 

 organisms. The essence of the idea of the grad- 

 ual development of organisms, however, was much 

 earlier, for it originated with Anaximander, upon 

 whose rude notion of the origin of the ' fish-men ' 

 Empedocles and other writers built up their theo- 

 ries. Empedocles added to the conception of devel- 

 opment a number of important principles. First, 

 he suggested that plant life preceded animal life, 

 and this suggestion was taken up and expanded by 

 Aristotle. Second, he concluded that the present 

 world of life was still formative or incomplete, a 

 modification of the general notion of Heraclitus. 

 Third, he suggested, with apparently remarkable 

 prevision, that the first organisms were formless 

 masses without distinctions of sex, that afterwards 

 the sexes were separated, and that the existing 

 modes of reproduction of the less perfect were 

 followed by the more perfect. This idea, as we 

 have seen, however, was not even remotely related 

 to our modern conception of primordial asexual 

 organisms, for his 'formless masses' were mytho- 

 logical monsters. 



Empedocles further set forth a rude doctrine of 

 the successive production directly from the earth 

 of larger animal types possessing greater or lesser 

 capacity of living and reproducing. The less per- 



