174 An Examination of Weismannism. 



latter at the expense of the former is a demonstration that such 

 a passage actually takes place. But a closer examination reveals 

 immense difficulties. In the first place, the molecules of the 

 body devoured are never simply added to those of the feeding 

 individual without undergoing any change, but, as far as we 

 know, they are really assimilated, that is, converted into the 

 molecules of the latter. We cannot therefore gain much by 

 assuming that a number of molecules can pass from the growing 

 somatic cells into the growing reproductive cells, and can be 

 deposited unchanged in the latter, so that, at their next division, 

 the molecules are separated to become the somatic cells of the 

 following generation l . 



l 6 O n 



The obvious answer to this is, that no one has ever 

 supposed " gemmules " to be merely " molecules" in the 

 chemical sense of this word ; nor has any one ever imagined 

 that they are "devoured" by the germ-cells into which they 

 pass. Of course, if this were the case — i.e., if gemmules serve 

 merely as food to the germ-cells — they would become disin- 

 tegrated down even to their chemically molecular structure, 

 and there would be an end of them as organized " carriers 

 of heredity." 



In the second place, it is asked: — 



How can such a process [i.e. the passage of gemmules into 

 growing germ-cells] be conceivable, when the colony becomes 

 more complex, when the number of somatic cells becomes so 

 large that they surround the reproductive cells with many 

 layers, and when at the same time, by an increasing division 

 of labour, a great number of different tissues and cells are 

 produced, all of which must originate de novo from a single 

 reproductive cell ? 



Here, again, the obvious answer is, that no one has ever 

 propounded such a statement. Far from supposing that 

 " all the different cells and tissues of a complex organism 



1 Essays, pp. 76-77, from which the following quotations are likewise 

 taken seriatim. 



