272 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 



fulh' matured and ready for fertilization. Many eggs after six or 

 eight days showed upon sectioning that they had approximated the 

 full blastular and in some cases the gastrular stages, although the 

 condition came about apparently by some sort of internal nuclear 

 arrangement, as no superficial cleavage furrows were observable and 

 no demarcation into cells was visible from the exterior until the third 

 or fourth day, when close inspection showed in some cases numerous 

 small vesicular or cellular outlines. 



In some instances definite organs were developed, though fre- 

 quently distorted and misplaced. Cross-sections of one embryo, for 

 example, showed such pronounced defects as two neural tubes an- 

 teriorly. Of the whole number of eggs operated upon only two devel- 

 oped into free-swimming tadpoles and these were apparently normal 

 as far as superficial examination disclosed. They have not yet been 

 sectioned. After sixteen days one died and the other was killed to 

 insure proper fixation for histological study. 



Apparently the white rather than the red corpuscles are the stimu- 

 lating agents which bring about development, because injections of 

 lymph, which contains only white corpuscles, produce the same effect 

 as injections of blood. Whether or not the fluid part of the lymph or 

 blood produced any effect could not be definitely determined from the 

 material at hand. 1 



Guyer thought that probably the cells which he intro- 

 duced were developing and not the egg. He did not recognize 

 that his experiment was a case of artificial parthenogenesis. 

 This, however, does not detract from the fact that he was 

 the first to cause the development of the unfertilized egg of 

 the frog by puncturing it, that he introduced blood into the 

 egg for this purpose, and that he succeeded in producing two 

 parthenogenetic tadpoles. 



Guyer's results were to a large extent confirmed by Batail- 

 lon. Bataillon found that mere puncturing of the egg of the 

 frog by a very fine needle could not produce any embryogenesis 

 but that a second factor was necessary, namely, that some of the 

 body liquids (blood of the frog or newt or fish) have to enter the 

 egg. "A considerable percentage of the eggs of Rana, touched 



i Guyer, Science, XXV, 910, 1907. 



