THEORY OF SEX ITS NATURE AND ORIGIN. 



119 



centrated expression. For the bodies, after all, as Weismann has 

 so clearly emphasised, are but appendages to this immortal chain 

 of sex-cells. 



We have already pointed out that the sex- cells are more or 

 less on a level with the Protozoa. If we only knew, they pro- 

 bably differ widely from them in those intricacies of nuclear 

 structure of which we only see the surface ; yet as single cells the 

 sex-cells are comparable with the Protozoa. For the moment, 

 let us study those simplest organisms. Even a student, shown 

 an extended series of unicellular forms, amoebae, foraminifers, 



The divergence of male and female cells from 

 primitive amoeboid indifference. 



sun -animalcules, infusorians, gregarines, and some of the 

 simplest algae as well, might gradually begin to group these 

 in his mind under three divisions. First there are highly active 

 cells, — infusorians of all sorts ; at the opposite extreme there 

 are quiescent forms, in which the life seems to sleep, and loco- 

 motion is almost absent, — the gregarines, ^d some unicellular 

 algae ; and between these there are forms which in a via media 

 have effected a sort of compromise between activity and pas- 

 sivity, which are without the cilia of the one or the self-contained 

 stagnancy of the other, but possess outflowings of their living 

 substance, — the familiar amoeboid processes. He would thus 

 reach, almost by inspection, a rough and ready classification 

 of the Protozoa, into active, passive, and amoeboid cells, — a 



