Origin of Sexuality 283 



biotic protoplasmic and specially bacterial ancestry. The 

 line of green plant advance seems to have resulted from for- 

 mation in these bacterial forms of autotrophic pigments, and 

 later the evolution of chromatin, that started sex differentia- 

 tion. The line of animal advance probably resulted from auto- 

 trophic bacterial organisms through formation of a saprophytic, 

 a parasitic, or an epibiotic dependence on plants or other animals, 

 and simultaneously or somewhat later through the evolution of 

 cliromatin as in plants, that gave rise to sex differentiation. 



In the evolution of the above described stages of conjuga- 

 tion in Algae as in Protozoa, it should be emphasized that the 

 simplest types are made up of cell-gametes that in size, shape, 

 and behavior to each other are apparently exactly alike. Both 

 equally attract, and are equally attracted, so that it is impos- 

 sible to speak of either cell as male or female gamete cell. From 

 the standpoint of stereoenergetics therefore, it seems to be 

 constantly suggested that equal amounts of cognitic energy 

 of opposite sign or quality energize both, and so cause balanced 

 union of isogamete cells. 



So the highly important distinction has to be drawn, that 

 sexuality as compared with maleness or femaleness are distinct 

 even though usually correlated conditions. For, while any 

 two complemental cells that fuse to form an organic unit are 

 sex cells, it only is when one of these becomes recognizably 

 different and behaves differently that we can speak of them 

 as male and female cells. From the one condition to the other 

 however, the most gradual advances are shown. 



But in Zygnema, Spirogyra, and others that are passive, and 

 which have conjugate cells exactly like each other, as well as 

 in Algse and Protozoa that form sperm and egg cells, the receiv- 

 ing cell is evidently so differently energized from the giving 

 cell that it draws the contents of the latter toward it. In the 

 case of motile gamete cells also, when even a slight difference 

 is established in size, one becomes the attracting, the other 

 the attracted, cell. The manner also in which, after fusion 

 of the conjugating cells in Spirogyra^ and in some Protozoa, 

 rapid energizing changes spread through the conjugated sub- 



