572 Mutations 



far as they protect the bearers of such charac- 

 ters against being crowded out by their more 

 poorly constituted competitors. 



However, the differentiating characteristics 

 of elementary species are only very small. How 

 widely distant they are from the beautiful adap- 

 tative organizations of orchids, of insectivorous 

 plants and of so many others ! Here the differ- 

 ence lies in the accumulation of numerous ele- 

 mentary characters, which all contribute to the 

 same end. Chance must have produced them, 

 and this would seem absolutely improbable, even 

 impossible, were it not for Darwin's ingenious 

 theory. Chance there is, but no more than any- 

 where else. It is not by mere chance that the 

 variations move in the required direction. They 

 do go, according to Darwin's view, in all direc- 

 tions, or at least in many. If these include the 

 useful ones, and if this is repeated a number of 

 times, cumulation is possible ; if not, there is 

 simply no progression, and the type remains 

 stable through the ages. Natural selection is 

 continually acting as a sieve, throwing out the 

 useless changes and retaining the real improve- 

 ments. Hence the accumulation in apparent- 

 ly predisposed directions, and hence the 

 increasing adaptations to the more specialized 

 conditions of life. It must be obvious to any 

 one who can free himself from the current ideas, 



