300 DARWINISM AND THE PROBLEMS OF LIFE 



" amphimixis " has originally nothing to do with 

 reproduction. 



This is perfectly clear in the case of the protozoa. 

 If we glance at the transitional forms between the 

 unicellulars and the multicellulars, we shall see how 

 "sexual" reproduction came gradually to spread. 



In the unicellulars the whole animal has to unite 

 with another to give amphimixis. This is really what 

 happens. Two protozoa, apparently of the same size 

 and appearance, put their cell bodies together, and 

 coalesce into one mass. After a time they separate 

 again, and the process of amphimixis is over. Here 

 we see clearly that amphimixis does not aim at 

 multiplication in its original form, because there are 

 two animals both before and after it. 



Do the protozoa confirm the view we adopted in 

 the seventh chapter that it is the object of amphimixis 

 to give the new organism a choice of the character- 

 istics of two " parents," so as to make it more 

 capable of different adaptations ? That is really the 

 case. The various characteristics of an animal's frame 

 are based on the rudimentary particles of the germ ; 

 in the case of the protozoa, in which body and germ 

 are one, this means in the nucleus of the cell. Now 

 it has been noticed that during the conjunction of two 

 protozoa the nucleus of one of them divides, and 

 transfers one half to the body of its companion, where 

 it blends with the half that has remained there. 

 Hence when the animals separate once more, the 

 nucleus of each contains a half of the rudimentary 

 particles of the other protozoon as well as half of 



