220 SCIENCE AND IMMORTALITY 



monly held, development is the result of germinal 



variation and selection. No offspring exactly 

 resembles its parents, and germinal variations 

 which favour in the struggle for existence will 

 survive, and thus the type may change. The 

 theory that variations due to use and disuse, or 

 otherwise acquired^ are inheritable, and may lead to 

 racial variation, is not now held, and only germinal 

 variations — variations due to peculiarities in the 

 germ-plasm — are considered to be inheritable, 

 and to have evolutionary influence. 



In considering, then, what the future will bring 

 forth, we have to consider what germinal varia- 

 tions may occur, and which of these are likely to 

 have survival-value. Such a consideration is really 

 beyond us. We cannot tell what variations are 

 likely to arise, and we can tell only very roughly 

 how they would be likely to fare. Who could 

 guess that an amoeba would evolve into a man ; 

 and what wonderful possibilities may not birds, 

 and beetles, and seals, and simians yet hold } 

 Regarded as an evolutionary product, man owes 

 his pre-eminence chiefly to favourable variations 

 in the muscles of his thumb and backbone, and in 

 the brain-cells in his third left frontal convolution. 

 An erect position set his forelimbs free ; apposition 

 of his thumb and forefinger gave him new manual 

 dexterity ; and the new cells in his brain gave him 



