50 FROM THE GREEKS TO DARWIN 



of the soul, imparts life, motion, and thought to 

 animals. He introduced the idea of primordial 

 terrestrial shme, a mixture of earth and water, 

 from which, under the influence of the sun's heat, 

 plants, animals, and human beings were directly 

 produced — in the abiogenetic fashion. Diogenes 

 of Apollonia (440- ), a late adherent of the 

 Ionian school, also derived both plants and ani- 

 mals from this primordial earth slime. This is 

 the prototype of Oken's Ur-Schleim, 



Xenophanes (576-480 b. c.) 



Xenophanes was the founder of the Eleatic 

 school, and is beheved to have been a pupil of 

 Anaximander. He agreed with his master so far 

 as to trace the origin of man back to the transi- 

 tion period between the fluid or water and the 

 soHd or land stages of the development of the 

 earth, but we do not know how far he elaborated 

 his ideas. The ultimate origin of life he traced to 

 spontaneous generation, believing that the sun in 

 warming the earth produces both animals and 

 plants. He is famous in the annals of science as 

 being the first to recognize fossils as remains of 

 animals formerly alive, and to see in them the 

 proofs that the seas formerly covered the earth, 

 and that water was the element from which the 

 earth emerged. Parmenides, his pupil, devel- 



