FACTS 223 



the bipolarity of living elements, since one of its forms the 

 prothallus is always derived from an asexual reproduction, 

 while the other the fern is always derived from sexual 

 reproduction. Our provisional hypothesis enables us to 

 class these two forms fern and prothallus in the two 

 states which we have defined as associated and dissociated- 



Besides this, there is a character which distinguishes 

 the state of the prothallus from the state of the fern. It is 

 that all karyokineses, or cellular divisions, are produced in 

 the fern along with the appearance of 2n chromosomes, 

 whereas in the prothallus they are produced with an ap- 

 pearance of n chromosomes only. (In the following chapter 

 we shall see what chromosomes and karyokinesis are, but 

 the logical order of thought leads us to place first the history 

 of alternating generation.) Accordingly, we can substitute 

 for prothallus state the denomination state of n chromosomes. 



Thus defined, the law of the two states becomes general. 

 In all animals a generation of n chromosomes alternates 

 with a generation of 2n chromosomes ; but, for the most part, 

 the generation of n chromosomes is included in the other as 

 a parasite. This generation of n chromosomes, or pro- 

 ihallus generation, constitutes the genital organs of the species 

 under consideration. It is solely in the generation of n 

 chromosomes that sexual maturation manifests itself 

 which proves once again that the two successive states of 

 living substance in alternating generation are related to 

 the bipolarity of the living element. Until something new 

 is known, we may admit at least as a model for the fixing 

 of our ideas the hypothesis that the prothallus state cor 

 responds with the associated state of bipolar elements, 

 while the state of 2n chromosomes answers to the dissociated 

 state of these same elements, 



