20 Heredity and Eugenics 



initiated under experimental control. There is keen search- 

 ing for c_\-tological evidence ; and the structure and behavior 

 of the sexual cells, through the whole process of their forma- 

 tion, during the act of fusion, and in the initiating activity 

 of the fertilized egg, are being subjected to all the scrutiny 

 that a developing technique can de'vise to discover the 

 mechanism of heredity. Moreover, cytological evidence is 

 being searched for not only to disco\'er a possible ph}'sical 

 basis for heredity, which would mean actual material 

 machinery, but also to discover the possible relations of 

 chemical and physical factors to this most fundamental 

 and obscure process. It is believed that it must be a 

 response, in terms of chemistry and physics, by a living 

 material substance. 



6. PR.A.CTICAL APPLICATIONS 



In a uni^'ersity atmosphere, the chief interest is probably 

 focused upon the attempt to reveal one of the so-called 

 "mysteries" of life, those mysteries which always invite 

 one to uncover them; but there is another aspect of these 

 problems worth considering. The experimental work that has 

 been done in the study of heredity and evolution has had a 

 ver}' important bearing upon the practical handling of plants 

 and animals, including the human animal. The applica- 

 tions have been made to plants most extensively, and 

 methods of plant breeding have been revolutionized. The 

 recognition that commercially "pure seed" is an extensive 

 mixture of different types or strains, has led to their 

 separation, and has changed the clumsy and inefficient 

 method of mass culture to the definite and exact method of 

 pedigree culture. As a consecjuence, the number of forms 

 made a\'ailable for culture has been multiplied enormously, 



