128 PLANT LIFE 



the structure of the organism and its environ- 

 ment. It is, further, almost a truism to 

 remark that the more complex the organism 

 the more patent is the perfection of its 

 adjustment. 



It is only when we get at closer quarters 

 with our problem that its intricacies really 

 begin to reveal themselves, and we are 

 obliged to confess that our search for the 

 causes, and even for the proximate agents by 

 which the production of appropriate mechan- 

 ical tissue is produced, has not been greatly 

 rewarded. Of the means whereby the corre- 

 lation is secured between functional need on 

 the one hand, and its peculiarity correct 

 satisfaction on the other, we have no positive 

 knowledge at all. 



It is easy to talk of " capacity to vary," 

 " survival of the fittest," and so on. Such 

 formulae have their uses as expressing rather 

 clearly certain definite facts, and as indicat- 

 ing in a general way some of the probable 

 or possible processes which have been con- 

 cerned in, or have at least influenced, the 

 modification of plants and animals in their 

 long course of evolution. But, after all, they 

 are only generalised descriptions, and give 

 us very little real or direct insight into the 

 nature of the processes themselves, and yet 

 it is precisely in the latter that the whole 

 secrets of evolution, and all that it implies, 

 are contained. In the particular example 

 we have been considering, we want to know 



