9 



ontogeny can be explained only by evolution, and 

 not by epigenesis.' 



A mental process, which consciously or uncon- 

 sciously plays a great part with evolutionists, and 

 helps to determine their conclusions, is characteristic 

 of the direction of their inquiries. They set out 

 from the fact that the characters of the parents, 

 often to the smallest detail, are transmitted to 

 children bv means of the germ or rudiment ; they 

 conclude that the active causes of all the complexity 

 that arises must be contained in the apparently 

 homogeneous germ, embryological differentiation 

 being a spontaneous process. It follows that the 

 apparent homogeneity is, in reality, latent com- 

 plexity which becomes patent during the progress 

 of ontogeny. Latent complexity implies a material 

 substratum, consisting of actual particles for which 

 manv different names have been found. As our 



j 



senses can give us no experimental knowledge of 

 these particles, which are so small as to be invisible, 

 modern evolutionists attempt to picture them, in 

 imagination, by reflecting all the visible characters 

 of the perfected organism upon the undivided egg- 

 cell, so peopling that globule of yolk with a system 

 of minute particles corresponding in quality and in 

 spacial arrangement with the larger parts of the 

 adult. 



Weismann has practised this art in the true 

 spirit of a virtuoso, and has elaborated it into a novel 

 mode of biological investigation. Take an example ; 

 ( It would be impossible,' he says in The Germplasm 

 (p. 138), 'for any small portion of the human skin 



