essential feature of Weismann' s germ-plasm 31 



Yes, they can, was Weismann's answer: 

 which, however, as I said, he afterwards 

 quahfied. Any detailed examination of his 

 theory would require a volume, has in fact 

 occupied many volumes. But the disconti- 

 nuity just referred to — duly considered — 

 suffices, I think, summarily and yet success- 

 fully to dispose of it. Let me try to make 

 this clearer. First of all I must ask you to 

 note that, so long as we confine our attention 

 to the unicellular organisms, there is no 

 special problem as to the inheritance of 

 acquired characters, nor in fact as to in- 

 heritance at all ; for, as Weismann himself 

 has shewn, there is here no natural death, and 

 therefore — strictly speaking — no succession 

 of generations. In his own words, " Natural 

 death occurs only among multicellular or- 

 ganisms, the single-celled forms escape it." 

 Eeferring to the well-known cell-division by 



