Hybridization 95 



seem to follow from the fact of the severe and universal 

 struggle in nature whereby plants are constantly forced 

 into new and strange conditions. But there is un- 

 doubtedly much variation which has sprung from more 

 remote causes, one of which it is our purpose to discuss 

 here. 



In the lowest plants and animals which are merely 

 single cells the species multiplies by means of simple 

 division or 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, might no longer reproduce the whole complex in- 

 dividual ; and, as all organs are necessary to the existence 

 of life, the organism may die if it is divided. 



Origin and function of sex. Along with this specializa- 

 tion came the differentiation into sex; and sex clearly 

 has two offices : to hand over the complex 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 organisms 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 may be constantly greater be- 

 cause of the impressions of the greater number of ancestors 



