Statement of Weismanris System (1886). 19 



making its own vat of nutrient material, and that it 

 was only the residual portion of the cell which was 

 afterwards able to grow and multiply. But although 

 the metaphor is thus necessarily a clumsy one, it 

 may serve to emphasize the all-important feature of 

 Weismann's theory — namely, the almost absolute 

 independence of the germ-plasm. For, just as the 

 properties of the yeast-plant would be in no way 

 affected by anything that might happen to the vat, 

 short of its being broken up or having its malt 

 impaired, so, according to Weismann, the properties 

 of the germ-plasm cannot be affected by anything 

 that may happen to its containing soma, short of the 

 soma being destroyed or having its nutritive functions 

 disordered. 



Such being the re'ations that are supposed to 

 obtain between the soma and its germ-plasm, we have 

 next to observe what is supposed to happen when, 

 in the course of evolution, some modification of the 

 ancestral form of the soma is required in order to 

 adapt it to some change on the part of its environ- 

 ment. In other words, we have to consider Weis- 

 mann's views on the modus operandi of adaptive 

 development, with its result in the origination of new 

 species. 



Seeing that, according to the theory, it is only con- 

 genital variations which can be inherited, all variations 

 subsequently acquired by the intercourse of individuals 

 with their environment, however beneficial such 

 variations may be to these individuals, are ruled out 

 as regards the species. Not falling within the 

 province of heredity, they are blocked off in the first 

 generation, and therefore present no significance at 



C % 



