FERTILIZATION AND HYBRIDIZATION 



"Vom Vater hab' ich die Statur, 

 Des Lebens ernstes Ftihrcn, 

 Vom Miitterchen die Frohnatur 

 Und Lust zu fabuliren." 1 



In these lines lies the whole problem of heredity and 

 fertilization. What everybody can see, Goethe has voiced 

 clearly and concisely in beautiful, simple words. We have 

 one part from the father, the other from the mother. Or, 

 as it is now usually put, the hereditary characters of the 

 two parents are combined in the offspring. 



It became the problem of scientific investigation to 

 seek out the cause of this phenomenon. It could not be 

 limited to man. The law mentioned by Goethe 1 must be 

 general, it must be true of the entire plant and animal 

 world, wherever two beings unite for the production of 

 progeny. Furthermore it cannot concern ordinary fertil- 

 izations only, but also those abnormal cases in which unlike 

 individuals, belonging to different varieties or species, 

 fertilize each other. The products of such crosses we 

 call hybrids, and for science they possess the great im- 

 portance that, in them, the manner in which the charac- 

 tertistics of the parents are combined can be studied more 

 easily and clearly than in the children of a normal union. 

 For the more the parents differ from each other, with 

 the greater certainty must it be possible to determine the 

 share of each in the characteristics of the offspring. 



1 Goethe, "Spriiche in Reimen," Gesammelte Werke, III, 83, 1871. 



