History of the Theory of Heredity. 55 



doubt traceable to the fact that, in most animals, the 

 egg is stationary, while the male cell can be conveyed 

 from place to place; but we must believe that there is 

 some more fundamental and primitive difference. 



Even if the phenomena of Parthenogenesis did not 

 show us that the part played by the ovum is more 

 essential to th6 perpetuation of the race than the part 

 played by the male cell, we should still be justified in the 

 belief that the difference in form corresponds to some 

 profound difference in function, and the possibility of 

 Parthenogenesis, shows beyond question that this is the 

 case. 



Parthenogenesis. 



Siebold has proposed the term parthenogenesis for the 

 power which is possessed by certain female animals, 

 especially the arthropods, to produce descendants without 

 sexual union with a male. 



The existence of this power was first pointed out by 

 Aristotle (De Generations Animalium, Lib. III., Cap. 

 10, 21, 22, 23). As this remarkable observer had no 

 means for exact research at his command, he was, of 

 course, unable to make use of rigid tests, or to furnish 

 the severely exact proofs which have been given us by 

 more modern naturalists ; but he gives many reasons for 

 suspecting that the unfertilized eggs of the honey-bee 

 may give rise to perfect animals without sexual union ; 

 and although we now know that some of the reasons 

 he urges do not really prove the case, yet modern sci- 

 ence has given the most conclusive proofs of the correct- 

 ness of his general conclusion. 



I shall devote considerable space to this subject in 

 order to show the unscientific reader that the existence 

 of fertile virgin female animals is proved by the obser- 



