120 PLANT-LIFE ON LAND [CH. 



were any directive influence determining the course 

 of inherited variation, and natural selection were 

 operative upon the variations thus produced, the 

 results which we see would be readily understood. 

 At present such directive influence, traceable to the 

 immediate accommodation of the organism to its 

 environment, is directly ruled out by certain inves- 

 tigators. But there are many who hold their opinion 

 in suspense on such questions. They look hopefully 

 in the direction of a theory involving some form or 

 other of the storing up of past experience, and its 

 perpetuation in the features of the race. By selection 

 among organisms with such memorised records the 

 facts of adaptation to the environment would become 

 intelligible. But of this the demonstration is not yet 

 come. 



Returning now, in conclusion, to the limited area 

 of sward with its varied inhabitants from which we 

 started this discussion, we shall see in it the result of 

 a balance struck by Organic Nature. On the one 

 hand is the fact of constant over-production of germs : 

 on the other is the imminence of adverse fate 

 threatening each life we see, while the field on which 

 this tense battle of the individual is being fought is 

 strewn with countless failures. Efficiency is the ruling 

 condition of existence, and it is maintained by selection 

 among multitudinous variants. If those variants are 

 favourable, an ever-increasing efficiency is what such 



