12 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 



prophecy of the importance of oxygen and oxidation in vital processes. 

 Anaxi menes also introdu ced the idea of abiogenesis (spontaneous 

 g eneration^ on iving substan ce), his jdea being that animals and p lants 

 *7 arose_ out of a primordial terrestrial slime wakene d jnto life by t he sun's 

 heat. This primordial terrestrial slime is perhaps a prophecy of 

 Oken's "Urschleim" or of protoplasm. 



Xenop liaiics (576-480 B.C.), probably another pupil of Anaxi- 

 mander, "agreed with his master so far as to trace the origin of man 

 back to the transition period between the fluid or water and solid or 

 land stages of the development of the earth." He was _the first to 

 recognize/£££^5 as the remains of animals once alive, and to see 

 in them proof mat once the seas covered the entir esurtace ot^ tne 

 earths 



Heraclitu s (535-475 B.C.), the jirst of a group of physicists, was th e 

 great propon ent of the philosophy of chang e. He _was imbued with 

 the idea that all was motion, that nothing was fix ed. ''Everything 

 / was perpetually transposed into new shapes. " Although Heraclitus 

 did n ot apply his ide as to living creatures and thei r evoluti ons, his 

 phil osophy was influential in moldmg thei deas of his success ors. 



E mpedocle s (495-435 B.C.) " took a great stride beyond his predeces- 

 sors, and may justly be called \\e. fpthpr ^f \\tp V^yo,\u^\r,r\ \Af^^ .... 

 He-helifiyedm Abiogenesis, or sp ontaneous generatio n, as the explana^ 

 ti on of the origin of l ife, bu t that >{ature does not produce the lo wer 

 a nd higher forms simultaneously or_ _gilbniit an pffnrf Plant. Hfe 

 rn mes f irsf ^ an d animal life developed onlv after a long series of tri als." 

 He thought that all creatures arose through the fortuitous combina- 

 tion of scattered and miscellaneous parts which were attracted or 

 repelled by the forces of love or hate (the two great forces in Nature). 

 Thus arose every sort of combination of parts, some more or less har- 

 monious and complete, others with ill-assorted organization, lacking 

 in some parts, double or triple in others. Some of these combinationsj 

 could not survive, because of their incompleteness and incongruity, 

 but "other forms arose which were able to support themselves and 

 multiply." This is a sort of vague prophecy of the survival of the 

 fitt est or of n a tural selectiom Four sparks ot truth may"~lTe futnid in 

 Empedocles' philosophy, "f irst^, that the development of life was a 

 gradual process; second, that plants were evolved before animals; 

 third, that imperfect forms were gradually replaced (not succeeded) 

 by perfect forms; fourth , that the natural cause of the production of 

 perfect forms was the extinction of the imperfect. " 



