MONISTIC EVOLUTION 137 



would destroy the argument of the evolutionist. In 

 this case, he would be hopelessly shut up to the con 

 clusion that * hens were before eggs ; and Haeckel 

 elsewhere informs us that the exactly opposite view 

 is necessarily that of the monistic evolutionist. Thus, 

 though it may often be convenient to speak of these 

 three kinds of cells as if they were perfectly similar, 

 the method of disappearance has immediately to 

 be resorted to, and they are shown to be in fact quite 

 dissimilar. There is indeed the best ground to suppose 

 that the one-celled animals and embryo-cells referred 

 to have little in common except their general form. 

 We know that the most minute cell must include 

 a sufficient number of molecules of protoplasm to ad 

 mit of great varieties of possible arrangement, and 

 that these may be connected with most varied possi 

 bilities as to the action of forces. Further, the em 

 bryo-cell which is produced by a particular kind of 

 animal, and whose development results in the repro 

 duction of a similar animal, must contain potentially 

 the parts and structures which are evolved from it ; 

 and fact shows that this may be affirmed of both the 

 embryo and sperm-cells, where there are two sexes. 

 Therefore it is in the highest degree probable that 

 the eggs of a snail and of a k man, though possibly 

 alike to our coarse methods of investigation, are as 

 dissimilar as the animals that result from them. If 

 so, the egg may be before the hen ; but it is as 

 difficult to imagine the spontaneous production of 



