468 HEREDITY AND DEVELOPMENT 



these and other alleged advantages of the theory are real ad- 

 vantages. Does the theory clarify our conception of inherit- 

 ance ? and does it suggest experimental work, on which, after 

 all, we must base our conclusions as to these abstruse questions ? 

 Do the advantages of the theory outweigh the difficulties ? 



Objections. — What we have stated above is not more than 

 an outline of a theory which Weismann has developed with 

 great subtlety and in great detail, and many objections may 

 occur to our statement of the theory which are well met in 

 the author's own presentation. But we may allude to a few 

 of the current criticisms. 



1. It has been objected that the whole concept of germinal 

 selection is visionary and unverifiable. But the same may be 

 said of modern speculations as to the constitution of matter ; 

 it may be said that the conception of an atom as a constellation 

 of electrons is visionary and unverifiable. The point, however, 

 is : does this hypothetical construction enable us to interpret 

 the facts better ? does it harmonise with visible facts ? is it con- 

 sistent with what we know of the behaviour of observable 

 living units ? It seems to us that an affirmative answer may 

 be given. The concept of germinal selection deals with an 

 invisible world, but it helps us to understand such facts as the 

 dwindling of useless parts, the definiteness of variation, the 

 excessive growth of more or less indifferent parts {e.g. some 

 decorations), the persistence of indifferent malformations for 

 a limited number of generations {e.g. six fingers in six successive 

 generations), and so on. 



2. It may be objected that we can hardly think of invisible 

 bodies such as determinants struggling for food. But why 

 not ? Size seems an irrelevant consideration. Cells which are 

 invisible to the naked eye are seen under the microscope strug- 

 gling for food. The germ-cells in the ovary of Hydra devour 

 one another just as really as the embryos of the dog- whelk in 

 their egg-capsules on the sea-shore, just as really as the locusts 



