PROTOZOA 321 



their change. It is then settled whether the variation is 

 to survive or not. If it is of such a character that the 

 organism can sustain the struggle for life, it is preserved 

 and transmitted to offspring ; if not, the animal 

 perishes, and with it disappear the variations of its 

 basic particles. Thus in the course of time those 

 of the innumerable variations of the basic particles 

 will survive that prove useful in the developed 

 organism. 



There is only one more reflection to make. What is 

 the conduct of the basic particles during amphimixis ? 

 As the ovum contains the basic particles of the mother 

 and her ancestors, and the spermatozoon those of the 

 father and his ancestors, the number of them must be 

 doubled when they unite. It will be fourfold at the 

 next amphimixis, and so on, until at last they fill the 

 cell-nucleus in immense numbers. We saw in the 

 seventh chapter that there are several basic particles 

 in the ovum for each organ, and that both the ovum and 

 the spermatozoon are capable of constructing several 

 different beings. We saw further that there is a force 

 which, in a way unknown to us, always selects the one 

 basic particle of each organ that is to build up the 

 particular organ. But even if this force prevents the 

 doubling or tripling of an organ in the developing body, 

 nevertheless the basic particles must increase so much 

 in a few generations by the eternal doubling at 

 amphimixis that there will at last be no room for them 

 in the nucleus. 



To fix a limit to this indefinite increase of the basic 



particles there must be some arrangement of the germ- 



x 



