388 AIM AND PROGRESS OF PHYSICAL SCIENCE. 



and floras of limited areas have, one and all, received 

 elucidation. Formerly natural affinity appeared to be a 

 mere enigmatical, and altogether groimdless similarity 

 of forms ; now it has become a matter for actual consan- 

 guinity. The natural system certainly forced itself as 

 such upon the mind, although theory strictly disavowed 

 any real significance to it; at present it denotes an 

 actual genealogy of organisms. The facts of palaeonto- 

 logical and embryological evolution and of geographical 

 distribution were enigmatical wonders so long as each 

 species was regarded as the result of an independent act 

 of creation, and cast a scarcely favourable light on the 

 strange tentative method which was ascribed to the 

 Creator. Darwin has raised all these isolated questions 

 from the condition of a heap of enigmatical wonders 

 to a great consistent system of development, and esta- 

 blished definite ideas in the place of such a fanciful 

 hypothesis as, among the first, had occurred to Groethe, 

 respecting the facts of the comparative anatomy and the 

 morphology of plants. 



This renders possible a definite statement of problems 

 for further inquiry, a great gain in any case, even should 

 it happen that Darwin's theory does not embrace the whole 

 truth, and that, in addition to the influences which he has 

 indicated, there should be found to be others which 

 operate in the modification of organic forms. 



While the Darwinian theory treats exclusively of the 

 gradual modification of species after a succession of 

 generations, we know that a single individual may adapt 

 itself, or become accustomed, in a certain degree, to the 

 circumstances under which it has to live ; and that even 

 during the single life of an individual a distinct progress 

 towards a higher development of organic adaptability 

 may be attained. And it is more especially in those 

 forms of organic life where the adaptability in structure 



