. 28 ANTICIPA TION AND INTERPRE TA TION OF XA TUBE. 



was handed down through all the Middle Ages, and 

 appeared in its crudest form as an explanation, not 

 only of the origin of the lowest forms of life, but 

 of the higher forms, even as late as the beginning 

 of this century. As a spurious naturalistic expla- 

 nation it was one of the greatest impediments to 

 the growth of the true Evolution idea. 



The law of Biogenesis, or of life from life, was 

 clearly stated in Harvey's famous and oft-quoted 

 dictum, omne vivnm ex ovo, but was not finally de- 

 monstrated until quite late in the present century. 

 The belief in spontaneous or direct origin from the 

 earth thus began amongst the Greeks as an expla- 

 nation of the origin of man and of the highest 

 forms of life ; it was gradually contracted to the 

 origin of the lower and smaller forms of life, and 

 finally, to the lowest invisible forms of bacteria, 

 until, as an outcome of the discussions which are 

 still fresh in our memory, between Pouchet and 

 Pasteur in France, and Bastian and Tyndall in 

 England, the theory of spontaneous origin of any 

 form of life, even the lowest, was completely 

 abandoned. 



