6 PROBLEMS OF FERTILIZATION 



with the uterus. Each one of the male animals (sperma- 

 tozoa) incloses an infinity of other animals both male and 

 female, which are correspondingly small, and these male 

 animals inclose yet other males and females of the 

 same species, and so forth in a series which includes 

 all the members of the species which are to be produced 

 up to the end of time. No difficulty was found in this 

 conception, for matter was still considered infinitely di- 

 visible and the atomic theory of matter was not yet 

 placed on a scientific basis. 



Thus was founded and flourished for its brief day the 

 school of the spermatists. Unhampered by any scien- 

 tific conception of matter, living or non-living, there was 

 no obstacle to the eye of faith and no impediment to 

 the age-old longing to make an intelligible universe out 

 of the scraps of experience. 



In the entire eighteenth century, although specula- 

 tion continued rife, there was only one notable contribu- 

 tion to our subject. This was the work of the Abbe 

 Spallanzani, Experiences pour servir a Vhistoire de la 

 generation des animaux et des plantes, published in Geneva 

 in 1785. His working hypotheses were naturally in 

 the spirit of the times. Theories of reproduction, 

 he says, may be reduced to two. 



The one explains the development of organisms mechanically, 

 the other supposes them to pre-exist, and waiting only for fer- 

 tilization to develop them. The second system has given birth 

 to two different parties, one believing that the organism is pre- 

 formed in the ovum, the other that it is performed in the 

 spermatozoon. 



Spallanzani believed that his observations destroyed 

 the epigenetic theory as propounded by Buff on and others, 

 because they demonstrated the existence of the " fetuses " 



