xv GENERAL ADAPTATIONS 313 



dissemination. All this was clearly seen and briefly stated 

 by Darwin, and has been somewhat fully developed by 

 myself in the work already quoted : but there is one point 

 on which I wish to make an additional suggestion. 



In my Tropical Nature I referred to Grant Allen's view 

 (in his Physiological ^Esthetics) that nuts were " not intended 

 to be eaten"; and in my Darwinism (p. 305) I adopted 

 this as being almost self-evident, because, though very 

 largely edible, they are always protectively coloured, being 

 green when unripe and brown when they fall upon the 

 ground among the decaying foliage. Moreover, their outer- 

 coverings are often prickly, as in the sweet-chestnut, or 

 bitter as in the walnut, while their seed-boxes are often very 

 hard, as in the hazel-nut, or intensely so, as in the Brazil-nut 

 and many other tropical species. 



But, on further consideration, I believe that this apparently 

 obvious conclusion is not correct ; and that nuts are, as a 

 rule, intended to be eaten. I am not aware that this 

 question has yet been discussed by botanists, and as it is 

 one of much interest and exhibits one of the curious and 

 indirect ways in which nature works for the preservation of 

 species, both in the vegetable and animal world, I will briefly 

 explain my views. 



The first point for our consideration is, that most nuts 

 are edible to some animals, and a large number are favourite 

 foods even to ourselves. Then they are all produced on 

 large trees or shrubs of considerable longevity, and the fruits 

 (nuts, acorns, etc.) are produced in enormous quantities. If 

 now we consider that in all countries which are undisturbed 

 by man, the balance between forest and open country, and 

 between one species and another, only changes very slowly 

 as the country becomes modified by geographical or cosmical 

 causes, we recognise that, as in the case of animals, the 

 number of individuals of each species is approximately 

 constant, and there is, broadly speaking, no room for another 

 plant of any particular kind till a parent plant dies or is 

 destroyed by fire or tempest. Imagine then the superfluity 

 of production of seed in an oak, a beech, or a chestnut 

 forest ; or in the nut-groves that form their undergrowth in 

 favourable situations. Countless millions of seeds are 



