66 VIGNETTES FROM NATURE. 



thrive, while those of them which fall on the 

 wrong ground die out and disappear at once. 

 In such a complex balance of life as this 

 it might at first sight seem as though no 

 new forms could ever be evolved. Where 

 the conditions to be complied with are so 

 numerous, where the interaction is so all- 

 embracing, surely it must be hard enough 

 just to keep up the ordinary requirements of 

 each species, without ever rising to higher 

 and still higher complications again. But if 

 we look a little closer into the problem, we 

 shall see that this very complexity itself pro- 

 duces the necessity for further advance. 

 Every plant and every animal must succeed, 

 not only partially, but always and all along 

 the line. The seed must escape the attacks 

 of birds or animals, for if it is once eaten up 

 it can never grow to be a plant at all. The 

 young shoot must escape the grubs and 

 locusts ; the flower must open and secure its 

 fertilisation ; the fruit must set and ripen its 

 seeds ; the seed again must be dispersed and 



