706 Studies in tJie Theory of Descent. 



the new form instantly equipped for the struggle 

 for existence, and adapted in all its organs and 

 systems of organs to the special conditions of its 

 new life. But would not this be " pure magic " ? 

 It is not thereby even taken into consideration 

 that here as in the cases of mimicry time and 

 place must agree. The requirements of a pre- 

 established harmony (" prastabilirte Harmonie ") 

 further demand that an animal fitted for special 

 conditions of life should only make its appearance 

 at that precise period of the earth's history when 

 these special conditions are all fulfilled, and so 

 forth. 



But he who has learnt to perceive the numerous 

 and fine relations which, in every species of 

 animal, bring the details of structure into harmony 

 with function, and who keeps in view the impelling 

 power of these conditions, cannot possibly hold 

 to the idea of a per saltum development of 

 animal forms. If development has taken place, it 

 must have occurred gradually and by minute steps 

 in such a manner indeed that each modification 

 had time to become equilibrated to the other 

 parts, and in this way a succession of modifica- 

 tions gradually brought about the total trans- 

 formation of the organism, and at the same time 

 secured complete adaptation to new conditions 

 of life. 



Not only abrupt modification however, but 

 every transformation is to be rejected when based 



