124 Artificial Parthenogenesis 



to make an attempt to raise parthenogenetic larvae of 

 the sea urchin beyond the larval stage and he succeeded 

 in one case in carrying the animal to the mature stage. 

 It proved to be a male. 



Better opportunities were offered when a method was 

 discovered which induced the development of the un- 

 fertilized eggs of the frog. In 1907, Guyer made the 

 surprising observation that if he injected lymph or 

 blood into the unfertilized eggs of frogs he succeeded 

 in starting development and he even obtained two 

 free-swimming tadpoles. ' ' Apparently the white rather 

 than the red corpuscles are the stimulating agents 

 which bring about development, because injections of 

 lymph which contains only white corpuscles produce 

 the same effects as injections of blood." Curiously 

 enough, Guyer thought that probably the cells which 

 he introduced and not the egg were developing. In 

 1910, Bataillon showed that a mere puncture of the 

 egg with a needle could induce development but he 

 believes that for the full development the introduction 

 of a fragment of a leucocyte is required. Bataillon 

 has called attention to the analogy with the writer's 

 results on lower forms, the puncturing of the egg 

 corresponding to the cytolysis of the surface layer of the 

 egg and the introduction of a leucocyte as the analogue 

 of the second or corrective factor. The method of 

 producing artificial parthenogenesis by puncturing 

 the egg has thus far been successful only in the egg of 



