250 LIFE AND HABIT. 



rather a shield and hindrance to our perception of our 

 own ignorance than an explanation of what these causes 

 are. 



The remarks made above will apply equally to plants 

 such as the misletoe and red clover. For the sake of 

 brevity I will deal only with the misletoe, which seems 

 to be the more striking case. Mr. Darwin writes : — 



" Naturalists continually refer to external conditions, 

 such as climate, food, &c, as the only possible cause of 

 variation. In one limited sense, as we shall hereafter 

 see, this may be true ; but it is preposterous to attribute 

 to mere external conditions, the structure, for instance, 

 of the woodpecker, with its feet, tail, beak, and tongue, 

 so admirably adapted to catch insects under the bark of 

 trees. In the case of the misletoe, which draws its 

 nourishment from certain trees, which has seeds that 

 must be transported by certain birds, and which has 

 flowers with separate sexes absolutely requiring the 

 agency of certain insects to bring pollen from one 

 flower to another, it is equally preposterous to account 

 for the structure of this parasite with its relations to 

 several distinct organic beings, by the effect of external 

 conditions, or of habit, or of the volition of the plant 

 itself" ("Natural Selection," p. 3, ed. 1876). 



I cannot see this. To me it seems still more prepos- 

 terous to account for it by the action of " natural selec- 

 tion" operating upon indefinite variations. It would 

 be preposterous to suppose that a bird very different 

 from a woodpecker should have had a conception of a 

 woodpecker, and so by volition gradually grown towards 

 it. So in like manner with the misletoe. Neither plant 



