Cross-Breeding and Hybridizing. 5 



simple division, or by budding. One individual, of itself, becomes two, and 

 the two are therefore recasts of the one. But as organisms multiplied and 

 conditions became more complex, that is, as struggle increased, there came a 

 differentiation in the parts of the individual, so that one cell or one cluster 

 of cells performed one labor and other cells performed other labor ; and 

 this tendency resulted in the development of organs. Simple division, there- 

 fore, could no longer reproduce the whole complex individual, and as all 

 organs are necessary to the existence of life, the organism dies if it is divided. 

 Along with this specialization came the differentiation into sex, and sex 

 clearly has two offices — to hand over, by some mysterious process, the com- 

 plex organization of the parent to the offspring, and also to unite the essen- 

 tial characters or tendencies of two beings into one. The second office is 

 manifestly the greater, for, as it unites two organizations into one, it insures 

 that the offspring is somewhat unlike either parent and is, therefore, better 

 fitted to seize upon any place or condition new to its kind. And as the 

 generations increase, the tendency to variation in the offspring must be con- 

 stantly greater, because the impressions of a greater number of ancestors are 

 transmitted to it. I have said that this office of sex to induce variation is 

 more important than the mere fact of reproduction of a complex organiza- 

 tion, for it must be borne in mind that the complexity of organization is 

 itself a variation made necessary by the increasing struggle for existence. 



If, therefore, the philosophy of sex is to promote variation by the union 

 of different individuals, it must follow that greatest variation must come 

 from parents considerably unlike each other in their minor characters. 

 Thus it comes that inbreeding tends to weaken a type and cross-breeding 

 tends to strengthen it. And at this point we meet the particular subject 

 which I am to present to you. I have introduced to you this preliminary 

 sketch because I contend that we can understand crossing only as we make 

 it a part of the general philosophy of nature. There are the vaguest notions 

 concerning the possibilities of crossing, some of which I hope to correct by 

 presenting this subject in its relations to the general aspects of the vegetable 

 world. 



We are now prepared to understand that crossing is good for the 

 species, because it constantly revitalizes offspring with the strongest traits of 

 the parents and ever presents new combinations which enable the individuals 

 ' to stand a better chance of securing a place in the polity of nature. All the 

 ' irther discussions of the subject are such as have to do with the extent to 

 which crossing is possible and advisable, and the mere methods of perform- 

 ing the operation. 



At this point I must digress for the purpose of defining certain terms which 

 it is necessary to use frequently. I use the term cross to denote the offspring 



