952 



LIFE : OUTLINES OF GENERAL BIOLOGY 



history. In a word, we must see it as an active being, and not merely 

 as passive to circumstances ; but as adaptive so far as may be from 

 within, as well to without. If so, we must keep in view that natural 

 selection does not act solely as favouring evolutionary progress, but 

 may also restrain it. It may, on one hand, prematurely wield the 

 shears of the third Fate, as well as on the other give helping and 

 sustaining hand with the first and second. Darwin no doubt saw 

 this ; but by no means always his later disciples, whose optimism of 

 natural selection, as all-sufficient explanation of evolution, needs 





Fig. 163. 



Variations (2-6) in Leaf-form in the Hart's Tongue Fern {Scolopendrium 

 vulgare). The type is shown in i. After Lowe. 



this protest on the part of organic life, which has its own evolutionary 

 springs within itself, and these not merely fated by ancestral heri- 

 tage, deep-lying and important though that be. So surely also with 

 the issues of that lifelong internal oscillation and struggle, of self- 

 maintaining and species-advancing, and thence active adaptations, 

 by which the issues of men's own lives, races, and histories have ever 

 been modified and varied; with its issues accordingly, in his mani- 

 fold developments and adaptations, too often towards extinction, 

 yet normally endeavouring towards survival, and even advance. 



What now for summary? Our botanic garden had among its old 

 trees a fine large weeping-ash, which beyond its continued use as a 



