Artificial Parthenogenesis in Frogs 273 



with the blood and immediately punctured, will develop, while 

 the same eggs squeezed out from the female frog will not develop 

 (when punctured)." Bataillon states that in the eggs thus 

 treated "he found at the beginning of the divisions outside the 

 kinetic figures, chromatin fragments accompanied by asters, 

 which fragments come probably from elements inoculated with 

 the needle. "1 In a recent paper Bataillon reaches the conclu-\ 

 sion that it is the leucocytes which cause the development (1913). ( 



A number of authors have succeeded in repeating these 

 experiments by Guyer and Bataillon, Dehorne,^ Henneguy,' 

 Brachet,* McClendon,^ and Loeb and Bancroft.* The last 

 named, however, have produced tadpoles also without the use 

 of blood or lymph. 



While the number of eggs which begin to segment when 

 punctured is not inconsiderable, very few reach the tadpole 

 stage. There is a difference in the response of the eggs of 

 various kinds of frogs to this treatment. 



The number of unfertilized eggs which began to segment 

 after puncture was according to Loeb and Bancroft greater in 

 the wood frog than in the leopard frog, and amounted in the 

 most favorable cases to about 40 per cent in the former. Only 

 2 of about 10,000 punctured eggs of the wood frog reached the 

 tadpole stage, but these died before they were able to swim. 

 The percentage of eggs of the leopard frog which reached the 

 tadpole stage was greater. From 700 punctured eggs of the 

 Southern leopard frog, 13 good morulae were isolated the next 

 day. On the third day, when the f ertihzed controls were in the 



'Bataillon, "La partheuogfinBse experimentale des amphibiens," Revue 

 genirale dea Sciences, XXII, 786, 1911; Compt. rend. Acad. Sc, CL, 996, 1910; 

 OLII, 920, 1911; CLII. 1120, 1911; CLII, 1271, 1911; CLVI, 812, 1913; Arch, 

 de Zo'ol. exper. et gSn., XLVI, 103, 1910. 



2 Dehome, Compt. rend. Acad. Sc, CL, 1451, 1910. 



» Henneguy, Compt. rend. Acad. Sc, CLII, 941, 1911. 



« Brachet, Arch, de Biol., XXVI, 337, 1911. 



sMcClendon, Am^ Jour. Physiol., XXIX, 298, 1911. 



• Loeb and Bancroft, Jour. Exper. Zool., XIV, 275, 1913. 



