ORIGIN OF SPECIES 227 



of eggs has been effected by exposing them to certain 

 rays. 



Jacques Loeb writes on the "activation of the un- 

 fertilized egg by ultra-violet rays": "The writer's 

 previous experiments have shown that any substance 

 which acts as a cytolytic agency can also produce 

 artificial parthenogenesis. It was found, indeed, that 

 the unfertilized eggs of the sea-urchin Arbaciay as 

 well as those of the annelid, Chaetopterus, can be 

 caused to develop by a short treatment with the 

 Heraeus quartz arc lamp."^^ 



One of the outstanding things brought to light by 

 the experiments on artificial parthenogenesis, is that 

 apparently "the egg is the future embryo." 



Loeb says: "The idea that the egg is the future 

 embryo is supported by the fact that we can call 

 forth a normal organism from an unfertilized egg by 

 artificial means; while it is apparently impossible to 

 cause the spermatozoon to develop into an organism 

 outside the egg."^^ 



Loeb at one time had "seven parthenogenetic frogs 

 over a year old, produced by merely puncturing the 

 eggs with a fine needle." At a later writing he re- 

 ported that "two more of the parthenogenetic frogs 

 over a year old died. Both were males. "^^ 



*5 Science, November 6, 1914. 

 ** The Organism as a Whole, 8, 9. 

 *7 Ibid., 125. 



