WEISMANWS ESSAYS UPON HEREDITY. 21 



secures "hereditary individual characters to form 

 the material upon which natural selection may 

 work." 



2. The second point to notice is that Weismann's 

 theory, if it is true, involves the triumph of the 

 Darwinian principle of natural selection, and will 

 therefore have to run the gauntlet with the modern 

 champions of Lamarckianism, including Herbert 

 Spencer. For Herbert Spencer is committed to 

 the view that what is a posteriori in the race is 

 a priori in the individual ; in other words, that 

 acquired characters are transmitted. According 

 to Weismann no such transmission is possible or 

 necessary. It is not possible if we are to accept 

 the theory of the continuity of the germ-plasm ; 

 and it is not necessary if we can explain the facts 

 without it. His contention is that we can ; that 

 the Lamarckianism which survived in Darwinism 

 was a deus ex mackind, which we can now dispense 

 with. The progressive increase of variability has 

 no meaning except as the progressive preparation 

 of material for natural selection to work upon. 

 The same law holds throughout. The conjugation 

 of unicellular organisms, the distinction and the 

 stereotyping of the distinction between somatic 

 and reproductive cells, the introduction of natural 

 death, the beginning of sexual reproduction, are 

 all explained by reference to the same end. And 

 when Darwin tells us that no flower is invariably 



