320 THEORETICAL BIOLOGY 



without restriction, it would soon crowd out all the others. 

 That is guarded against by the struggle for existence, in which 

 all animals compete with one another, a struggle that makes 

 for balance in the world, but at the same time permits of a 

 finer and finer selection ; for only the " best adapted " 

 organisms are capable of survival. 



In order to enter more closely into this idea, let us first 

 of all neglect the super-mechanical properties of animals, 

 and regard them purely as machines, having neither builder 

 nor director : then all the protoplasm in the world appears 

 as a substance undergoing a kind of fermentation, and broken 

 up into a great variety of parts — a substance that, during its 

 changes, is continually being influenced and shaped by physical 

 and chemical agencies, until machines are evolved that are all 

 adapted to one another. 



It certainly requires a powerful imagination to assume 

 that any machine capable of functioning could arise in this 

 way. But the Darwinians provide the requisite imagination. 

 Unfortunately, they carefully avoid the more serious conse- 

 quences of their doctrine. 



All the physical and chemical agencies are supposed, by 

 their external influence, to carry out the creation of form 

 on a substratum to which no properties can be ascribed 

 other than great power of reproduction and variability. As 

 soon as we presume any tendency whatsoever in the fermenta- 

 tive process to have a goal or give a direction, we are forsaking 

 the Darwinian basis. In this respect it is essentially different 

 from Lamarckism. 



The direction followed by the shaping is exclusively 

 dependent on external factors. Now animal machines do not 

 consist exclusively of external organs, but also of internal, 

 and these cannot be influenced directly by external agencies. 

 How are we to imagine the genesis of such organs ? Is there 

 a struggle for existence even among the organs ? Roux put 



