CHAPTER V. 

 THE PERPETUATION OF THE NEW SPECIES. 



As every new individual is the result of the mating 

 of two gametes, forming a zygote, and as a species ori- 

 ginates either from one, or from a fewofsuchzygotes, 

 multiplication is necessary to perpetuate the species. 



The transmittal of the constitution of the parent to the 

 offspring we call heredity. 



What do we know of it? 



Unfortunately: absolutely nothing. 



Heredity of course, deals in the last instance with the 

 constitution of the gametes, and of the constitution 

 of these gametes we know nothing. 



One has tried to get at the constitution of the game- 

 tes by mating gametes of different constitution, and 

 by recording the behaviour of the zygote so obtained. 



The results show that gametes derived from indivi- 

 duals, differing from one another in one respect only, 

 f . i. from plants, differing but slightly in the color of 

 their flowers, give other results, than follon upon the 

 mating of gametes derived from individuals which 

 differ in several respects. 



If we mate two gametes, obtained from parents who 

 differ in one respect only, the hybrid produced is di- 

 gametic e. g. forms only two kinds of gametes, one 

 kind of which is identical in constitution with the ga- 

 metes produced by one of the monogametic parents 



