366 DARWINISM AND THE PROBLEMS OF LIFE 



may recall, for instance, the vascular system of the 

 amphibians and birds ; the former have clearly a much 

 more ingeniously constructed heart than the latter. 



In the individual development of an animal, where 

 there seems to be an end, the processes are regulated 

 by natural selection, a mechanical principle. The germ 

 cells give rise to others in unbroken succession and also 

 the bodies surrounding them, which are continually 

 dissolved again into inorganic matter. Thus the 

 causal series of the living matter continually sends out 

 side-branches, as it were. The main trunk endures 

 uninterruptedly as life ; the effects of the side-branches 

 lead into the inorganic world and continue indefinitely 

 there as lifeless processes. 



If the construction of a living thing were the aim of 

 the germ cells, impelling them to realise it by their 

 development, how is it that it so often fails .'' Why are 

 there mis-births ? Why, above all, is the " end " no 

 longer fully attained when natural selection has ceased 

 to act ? Surely the degenerations effected in panmixis 

 show clearly enough that the ontogenesis is not aiming at 

 an immutable purpose. If natural selection ceases, the 

 harmony of development is always, though gradually, 

 disturbed, and some misshapen object formed. Civilised 

 man is always inferior in strength, hearing, and sight to 

 bis ancestors and his savage fellows. How is it that the 

 end has suddenly lost its force in his case ? 



It is clear, therefore, from panmixis that there is no 

 end controlling the development of animals with a view 

 to its own realisation. Such an end would not be 



