66 THE EVOLUTION OF CONTINUITY 



that an act of nuclear fusion in the terminal basidium on the 

 mushroom's gill which occurs just before the formation of 

 the spores is a sexual act. 



This view will without doubt be contested, but it is 

 pertinent to ask, What other significance can nuclear fusion 

 have ? Why should the nuclei of two protoplasts fuse 

 together, if the protoplasts are not terminal elements of the 

 cycle ? The whole principle of Individual growth is cell 

 and nuclear division through which elements capable of 

 fusion are restored or reproduced. If the reader refers again 

 to the description of the fertilisation process in Eurotium he 

 will see that here also there is a nuclear fusion in the young 

 ascus, and the question arises, Is not this the true conjugation 

 act here, and are not the ascogenous branches or buds pre- 

 fertilisation phenomena ? According to the quoted descrip- 

 tion there is first gamete-fusion, then protoplast division, and 

 then fusion again ; a difficult sequence to comprehend. 

 It might well be that the ascogenous buds contain the 

 female gametes, and that the ascus contains the male and 

 female gametes which he together for a while before fusing. 

 Our belief in any case is that the formation of false tissue is 

 essentially concerned with sexual reproduction ; and it 

 may be remarked that " terminal compression " in the 

 shape of the multiplication of preceding vegetative continuity 

 has clearly this significance in higher types of organism, as 

 will be shown when we come to treat of certain Hydrozoa 

 and Phanserogams. 



