THE GERM-PLASM 73 



the very first Galton takes into consideration the comphcations 

 or the germ-substance caused by sexual reproduction, which, as 

 '\vill be shown subsequently, are due essentially to the fact that 

 the germ-plasm contains many, and not a single specimen of 

 each primary constituent, and that these are present in various 

 modifications. It is this struggle between the hotnologous 

 primary constituents which Galton refers to in the passage just 

 quoted, which indicates that first one, and then another, reaches 

 the desired spot, without any definite order being observed. 

 This conception appears still more plainly in another passage, 

 in which he compares the germ-plasm (the ' stirp ') to a nation, 

 and those gemmules 'that achieve development,' — i.e., become 

 transformed into the corresponding parts of the body — 'to 

 the foremost men of that nation, who succeed in becominof its 

 representatives.' 



Excellent as these similes are in themselves, I cannot help 

 thinking that they lead to error if intended as an explanation 

 of ontogeny. If we take up the position which Galton occupies 

 with regard to the essential part of the theory of pangenesis, we 

 must suppose that a large number of gemmules — many more 

 than are necessary for the construction of the body — are con- 

 tained in the stirp ; that is, in the germ-substance of the fer- 

 tilised Qgg. For only one gemmule is required for each cell of 

 the body, but nevertheless a large number are present ; and 

 these, so to speak, struggle for the precedence, the successful 

 gemmule alone becoming converted into the cell which is to be 

 formed. In this conception the fact is entirely overlooked 

 that ontogeny itself cannot possibly depend on this struggle, 

 but would take place just the same if only ojie gemmule were 

 present in the 'stirp' for each cell, and that the cause for the 

 progress of development must therefore be sought elsewhere 

 than in the rivalry between homologous gemmules : it must be 

 due to the right succession of the gemmules. Galton considers 

 that the ' purely step-by-step-development ' assumed by Darwin 

 in his theory of pangenesis is insufiicient, but I think, neverthe- 

 less, that Darwin's opinion is the more correct one. 



Neither does Galton's simile of the swarm of insects seem to 

 me to be appropriate as an explanation of the struggle between 

 homologous gemmules derived from diflferent ancestors. Even 

 if the gemmules in the 'stirp' were in perpetual motion, and if 

 on this depended the decision as to which of them obtained the 



