Chap. XXI. SELECTION. 249 



of the rock, and the slope of the precipice, — events and circum- 

 stances, all of which depend on natural laws ; but there is no 

 relation between these laws and the purpose for which each 

 fragment is used by the builder. In the same manner the 

 variations of each creature are determined by fixed and im- 

 mutable laws ; but these bear no relation to the living struc- 

 ture which is slowly built up through the power of selection, 

 whether this be natural or artificial selection. 



If our architect succeeded in rearing a noble edifice, using the 

 rough wedge-shaped fragments for the arches, the longer stones 

 for the lintels, and so forth, we should admire his skill even in 

 a higher degree than if he had used stones shaped for the 

 purpose. So it is with selection, whether applied by man or by 

 nature ; for though variability is indispensably necessary, yet, 

 when we look at some highly complex and excellently adapted 

 organism, variability sinks to a quite subordinate position in 

 importance in comparison with selection, in the same manner as 

 the shape of each fragment used by our supposed architect is 

 unimportant in comparison with his skill. 



