176 THE BREEDING OF ANIMALS 



not undergo in any way the influence of the first male; 

 in reality, what takes place is as if two different females 

 were involved, mated with the same male or with two 

 different males." 



The conclusion seems very plain that the practical 

 breeder has little interest in the subject of telegony. 

 While it is difficult or impossible to prove by direct 

 experiment that telegony does not exist, it is also true 

 that no one by direct experiment has ever been able to 

 produce any result which could not be explained on some 

 other basis than that of telegony. All of the supposed 

 cases of telegony can likewise be explained on some other 

 basis than the assumption that a previous impregnation 

 is lasting in its effect and may influence subsequent off- 

 spring. 



163. Xenia in animals. In plants the effect of cross- 

 pollination in certain cases is to be observed in the fruits. 

 Gardeners have long believed that the watermelons and 

 citrons should not be planted in near-by locations because 

 the pollen from the citron would injure the quality of 

 the melon. Such injury really does not occur in this 

 particular case but similar effects are present in other 

 plants. When ordinary white corn is fertilized with 

 pollen from a black variety, the grains so pollinated are 

 black or mottled while other grains on the same ear are 

 white. An explanation for this phenomenon is to be 

 found in the fact that there are two cell nuclei in the ovum 

 and two nuclei in the pollen cell. The primary nuclei 

 of the two cells unite to form the daughter nucleus of the 

 new cell. The two secondary nuclei likewise unite in 

 the formation of the endosperm. In the case of cross- 

 pollination of black and white corn it is the color of the 

 endosperm which exhibits the influence of the crossing. 



