424 TRANSACTIONS AND PROCEEDINGS OF [Sess. lvi. 



digestion of the living achromatic plasm, whether this be 

 in a non-specialised condition as endonucleolar or archo- 

 plasmic matter, or in the specialised condition forming the 

 frameworks of the nuclear and other organs. 



The union of the trophic centres (archoplasmic and 

 endonucleolar) of the two conjugating cells by " their mutual 

 molecular attraction " (Ryder), will result, as soon as the 

 activities of the female centre have been roused, by the want 

 of nourishment ; — a want which will make itself felt, sooner or 

 later, as, to all intent and purpose, the male trophic centre acts 

 as a parasite. The corresponding organs of the conjugating 

 cells, such as nuclear chromosomes, nucleoli and paranuclear 

 chromatic elements, are only of secondary importance during 

 the act of conjugation, and they may, or, what is more 

 likely, may never fuse with one another. 



We must distinguish between fertilisation and heredity, as 

 Boveri pointed out in his famous paper on Ascaris mcgalo- 

 cephala. Fertilisation will be equivalent to the restoration 

 of trophic influence of tlie " female " centre over its organs, 

 and to a satisfied hunger of the " male " centre. Heredity 

 will be bound up mainly with the performance of those func- 

 tions of the various organs which are required for the main- 

 tenance of the newly formed trophic centre : functions which 

 will be performed as well as environmental conditions will 

 allow ; functions which, gradually, will become modified by 

 environment, and which, as they become modified, will pro- 

 vide the trophic centre with a new kind of food, and thus 

 lead perchance to Evolution. 



