118 THE ADVANCE OF SCIENCE 



wrongfully attributed to Harvey, 'Omne 

 vivum ex ovo,' that great physiologist be- 

 lieved in spontaneous generation as firmly 

 as Aristotle did. And it was only in the 

 latter part of the seventeenth century, 

 that Redi, by simple and well-devised ex- 

 periments, demonstrated that, in a great 

 number of cases of supposed spontaneous 

 generation, the animals which made their 

 appearance owed their origin to the ordi- 

 nary process of reproduction, and thus 

 shook the ancient doctrine to its founda- 

 tions. In the middle of the eighteenth 

 century, it was revived, in a new form, by 

 Needham and Buffon ; but the experi- 

 ments of Spallanzani enforced the conclu- 

 sions of Redi, and compelled the advo- 

 cates of the occurrence of spontaneous 

 generation to seek evidence for their hy- 

 pothesis only among the parasites and the 

 lowest and minutest organisms. It is 

 just fifty years since Schwann and others 

 proved that, even with respect to them, 



