32 FROM THE GREEKS TO DARWIN 



doctrine of abiogenesis, or generatio cequivoca 

 — the spontaneous origin of life from lifeless 

 matter. This fallacy exerted a most potent influ- 

 ence in shaping the crude theories of Evolution 

 which were advanced during the seventeenth and 

 eighteenth centuries, the absurdity of these theo- 

 ries reacting unfavorably upon the true evolu- 

 tion idea by throwing it into discredit. 



The accumulation of the natural evidences of 

 Evolution was the work of centuries. Besides the 

 advances in astronomy, geology, and physical 

 geography, there w^as the slow upbuilding of the 

 great branches of biology. First came correct 

 ideas of structure or comparative morphology of 

 animals and plants, and connected with this the 

 structure of extinct forms preserved as fossils; 

 with this knowledge developed an appreciation 

 of the meaning of variations and of gradual de- 

 velopment in structure, and the meaning of ves- 

 tigial or degenerate structures. Then came the 

 knowledge of function and the physiology, first 

 of man, then of the lower animals ; then the true 

 ideas of individual development from the egg, or 

 embryology, connected with which many fallacies 

 were current. Finally, natural environment be- 

 gan to be studied, or the relation of animals and 

 plants to each other and to the surface of the 

 globe, in connection with distribution. In short, 

 Evolution needed materials for induction. Un- 



