72 THE GERM-PLASM 



a similar kind ; and I imagine that that kind of determinant 

 which has to control a particular cell, multiplies considerably 

 by division before — and perhaps even during — the process or 

 determination. This view is completely borne out by Ruckert's 

 interesting observations. 



Every cell during the whole period of ontogeny is, however, 

 controlled — not only as regards its structure, but also in respect 

 of its mode of division — by 2i single determinant only. The in- 

 active determinants remain without exerting any influence on 

 the cell-body ; they how^ever determine the architecture of the 

 id, and therefore the further formation of the embryo also. For, 

 indeed, the mode of disintegration of the id into smaller groups 

 of determinants is necessitated by its architecture. 



I have above attributed to the determinants forces of attrac- 

 tion which take part in the configuration of the structure of the 

 ids. Such forces must be present, for otherwise the id could 

 not possess a definite architecture ; but I do not wish it to be 

 understood that these forces are the principal factors in the 

 arrangement of the determinants. They are concerned in con- 

 necting together the parts of which the determinants are com- 

 posed, and not in their continual rearrangement during the 

 course of ontogeny. It is primarily always the inherited definite 

 architecture of the id of germ-plasm which results mechanically 

 in the idic figure of the subsequent stages ; disarrangements in 

 this architecture are due to the unequally vigorous increase of 

 the various kinds of determinants, all of which naturally are 

 definitely determined beforehand. The arbitrary or accidental 

 action of the forces of attraction takes no part at all in this 

 process. 



I must emphasise this view particularly, in contrast to that of 

 Galton, who speaks of ' repulsions and affinities ' of the gemmules 

 which compose the ' stirp."' He compares the masses of these 

 gemmules, which undergo active and incessant changes of their 

 mutual positions owing to attraction and repulsion, to a swarm 

 of flying insects, in which • the personal likings and dislik- 

 ings of an individual may be supposed to determine the posi- 

 tion that he occupies in it." Witli this view I can by no means 

 agree, for it rests on the assumption that the germ-substance is 

 composed of many homologous gemmules (• competing germs ') 

 wiiich struggle for the supremacy, onlv those which are success- 

 ful determining the cliaracter of the future organism. P'rom 



