84 An Examination of Weismannism. 



" in these lower plants, the separation between somatic 

 and reproductive cells is slight/' in the facts to which 

 he alludes we appear to have good evidence of an 

 influence exercised by somatic cells upon the germinal 

 contents of reproductive cells. And if such an influence 

 is capable of being exercised in the case of "these 

 lower plants," it follows that there is no such absolute 

 separation between somatic tissues and germ-plasm as 

 Weismann's theory requires. Moreover it follows 

 that, if the essential distinction between germ-plasm 

 and somato-plasm (or " somatic idioplasm ") is thus 

 violated at the very foundation of the multicellular 

 organisms, there ceases to be any a priori reason for 

 drawing arbitrary limits, either as to the level of organ- 

 ization at which such i; transmission of somatogenetic 

 variation has occurred," or as to the degree of detail 

 into which it may extend. Both these matters then 

 stand to be tested by observation ; and the burden of 

 proof lies with the school of Weismann to show at 

 what level of organization, and at what degree of 

 representation, somatogenetic changes cease to repro- 

 duce themselves by heredity. 



Passing on, then, to higher levels of organization, 

 and therefore to higher degrees of representation, 

 I shall endeavour to show that this burden of proof 

 cannot be discharged. For I shall endeavour to 

 show, not merely, as just shown, that there ceases 

 to be any a priori reason for drawing arbitrary 

 limits with respect either to levels of organization 

 or to degrees of representation, but that, as a matter 

 of fact, there are no such limits as the passage above 

 quoted assigns. On the contrary, I believe there 

 is as good evidence to prove the not unfrequent 



