THE LAMARCKIAN PRINCIPLE 51 



fact the power of changing and a change of environment 

 awakens this power. The hard thorny plants so common in 

 the desert have become adapted to their surroundings. But 

 the environment has not given them their character. The 

 environment to which they have adapted themselves consists of 

 camels and other hard-mouthed hungry animals that would 

 devour and exterminate an unprotected plant. That the dry 

 air cannot cause the production of thorns is shown by the fact 

 that many desert plants are soft and succulent, protecting 

 themselves by a bitter or acrid flavour. Everywhere we see 

 a close correspondence between organisms and their en- 

 vironment, and yet it is often impossible that the environment 

 can have acted on the organisms so as to cause them to adapt 

 themselves each in its particular way. 



It is easy to show how powerless it is. The " locks and 

 keys" of the sycamore (Acer pseudo-platanus) twirl round in 

 the wind, when it breaks them off from the branch, and serve to 

 carry the seeds some way from the parent tree to a place where 

 there may be room for a young sycamore to grow. The con- 

 ditions here are the occupation of the ground near at hand by 

 the parent tree and the possibility of finding room to live and 

 thrive at some distance. Besides this there is the frequency of 

 sufficient wind. But none of these conditions can possibly pro- 

 duce this particular contrivance called, by botanists, a samara, 

 for carrying the seed. Some plants have a kind of spring which 

 throws their seeds to a distance. This too must have been 

 developed without any aid from external conditions, though it is 

 an adaptation to them. 



One more example from the vegetable world. The fruits of 

 many plants are admirably suited to attract birds who eat them 

 and scatter the seed far and wide, so that the species extends 

 its range. The strawberry is splendidly adapted to that part of 

 its environment which we call the Blackbird. Yet it cannot 

 have been influenced by the requirements of the palate to which 

 it appeals so forcibly. On its own initiative the strawberry plant 

 produced a marvel of succulence and flavour : this the Blackbird 

 happens to appreciate and, unconsciously, pays for what he receives. 



