INADEQUACY OP NATURAL SELECTION, ETC. 635 



for the mutual dependence we look in vain. We find entire 

 dependence on the one side and none on the other. Between the 

 parts devoted to individual life and the part devoted to species- 

 life, there is no division of labour whatever. The individual 

 works for the species ; but the species works not for the indivi- 

 dual. Whether at the stage when the species is represented by 

 reproductive cells, or at the stage when it is represented by eggs, 

 or at the stage when it is represented by young, the parent does 

 everything for it, and it does nothing for the parent. The 

 essential part of the conception is gone : there is no giving and 

 receiving, no exchange, no mutuality, 



But now suppose we pass over this fallacious interpretation, 

 and grant Professor Weismann his fundamental assumption and 

 his fundamental corollary. Suppose we grant that because the 

 primary division of labour is that between somatic cells and 

 reproductive cells, these two groups are the first to be differen- 

 tiated. Having granted this corollary, let us compare it with 

 the facts. As the alleged primary division of labour is universal, 

 so the alleged primary differentiation should be universal too. 

 Let us see whether it is so. Already, in the paragraph from 

 which I have quoted above, a crack in the doctrine is admitted : 

 it is said that " this differentiation was not at first absolute, and 

 indeed it is not always so to-day." And then, on turning to 

 page 74, we find that the crack has become a chasm. Of the 

 reproductive cells it is stated that " In Vertebrata they do not 

 become distinct from the other cells of the body until the embryo 

 is completely formed." That is to say, in this large and most 

 important division of the animal kingdom, the implied universal 

 law does not hold. Much more than this is confessed. Lower 

 down the page we read " There may be in fact cases in which 

 such separation does not take place until after the animal is com- 

 pletely formed, and others, as I believe that I have shown, in 

 which it first arises one or more generations later, viz., in the buds 

 produced by the parent." 



So that in other great divisions of the animal kingdom the 

 alleged law is broken ; as among the Coelenterata by the Jfydrozoa, 

 as among the Mollusca by the Ascidians, and as among the 

 Platyhelminthes by the Trematode worms. 



Following this admission concerning the Vertebrata, come 

 certain sentences which I partially italicize : 



"Thus, as their development shows, a marked antithesis exists between 

 the substance of the undying reproductive cells and that of the perishable 

 body-cells. We cannot explain this fact except by the supposition that each 

 reproductive cell potentially contains two kinds of substance, which at a 

 variable time after the commencement of embryonic development, separate 

 from one another, and finally produce two sharply contrasted groups of cells." 

 (p. 74) 



