198 TRANSMISSION OF ACQUIRED CHARACTERS 



ovum are distributed and allowed to express themselves. In 

 the germ-cell lineage they are kept concentrated and latent.* 



In any case the germ-cells in the reproductive organs are not 

 actively functioning elements of the body ; they are in a quite 

 peculiar way apart from the general soma ; and Weismann has 

 reasonably emphasised the difficulty of picturing any means 

 whereby the modification of a particular corner of the body can 

 react upon the germ-cells in a manner so specific that these can, 

 when they develop, reproduce the particular parental modification 

 or any approach to it. This argument, and the answers to it, 

 must be carefully considered. 



i. The Germ- cells may be affected by the Body.— In the 

 first place, it has been answered that the body does undoubtedly, 

 in some cases, exert some influence on the gonads, so that the 

 difficulty is reduced to this : Can a modification of part of the 

 body exert a specific or representative influence on the germinal 

 material ? 



But what is the precise nature of the alleged influence of 

 the body on the gonads ? It is pointed out that nervous 

 changes can excite the reproductive organs, that food-stuffs 

 may increase their activity, that alcohol and other stimulants 

 may influence them, and so on. But there is a great difference 

 between any such excitation of the gonads and the propagation 

 of a particular modification, let us say, from the skin to the 

 germ-cells. And there is a great difference between a poisoning 

 of the germ-cells along with the body, and the influencing of them 

 in a manner so specific that they can, when they develop, reproduce 

 the particular parental modification. (See Misunderstanding VII.) 



* In certain conditions, as yet unknown, certain body-cells may revert 

 to a primitive mode of behaviour — like some kinds of criminals in society. 

 Thus the cells which develop into cancerous growths behave in some 

 ways like germ-cells, especially in their mode of division. (See the 

 researches of Farmer, Walker, and Moore.) But such cases need not 

 lead us to Hertwig's extreme conclusion that every cell is potentially a 

 germ -cell. 





