Vlll TRANSLATOR S PREFACE. 



tially neuter, there seemed to be no other explana- 

 tion of the phenomenon, than that reproduction by 

 ova was as much an accessory as a fundamental 

 process. The beautiful researches of Kiichenmeis- 

 ter and Van Beneden showed that the tapeworm 

 which infests the human and other intestines, pro- 

 duces, as its immediate progeny, creatures exceedingly 

 unlike itself, and destined to live within the body of 

 an animal of a very different character from that in- 

 habited by their parent. Chamisso proved that there 

 are mollusks (Salpce) which by ova produce others 

 devoid of reproductive organs, but which, in the 

 absence of these structures, give rise to the sexual 

 individuals by a kind of gemmation. Saars' obser- 

 vations led him to believe that the Polyps present 

 similar phenomena. How, then, were all these excep- 

 tional facts to be explained? In what light was 

 sexual generation to be regarded? Were animals 

 to be considered as being produced indiscriminately 

 by two distinct processes — gemmation and ova- 

 development ? 



In the following pages the author has grouped all 

 the phenomena, in accordance with their real affinities, 

 and, as the result of this subjective mode of inquiry, 

 he has reduced all the varieties of generation to one 

 common law, which he has termed Genea-genesis. 



