Fig. 25. Copy of the engraved title appearing in one edition of Harvey's dissertation 

 on generation as shown on p. 139 of Early Theories of Sexual Generation by E. J. Cole. 

 Observe the words "ex ovo omnia" upon the egg which Jupiter is opening. Various animals 

 are emerging from the egg. 



Fig. 26. Copy of Hartsoeker's figure of human spermatozoan. containing the homon- 

 culus or "little man," published in 1694. This figure represents a marked preformationist 

 conception of development. However, it is to be noted that Hartsoeker later abandoned 

 the preformationist concept as a result of his studies on regeneration. 



54 



