276 Heredity. 



nature of tlic rock, and the slope of the precipice — 

 events and circumstances all of which depend on natuial 

 Jaws; but there is no relation between tliese laws and 

 the pui'pose for which each fragment is used by the 

 builder. In the same manner the variations of each 

 creature are determined by fixed and immutable laws; 

 but these bear no relation to the living structure which 

 is slowly built up by the jiower 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 arclies, 

 the longer stones for the lintels, and so forth, we should 

 admire his skill even in a higher deirree than if he had 

 used stones shaped for the purpose. So it is with selection, 

 whether applied by man or by nature; for though vai-ia- 

 bility is indisputably necessar}', yet when we look at some 

 highly complex and excellently adapted organism, varia- 

 bility sinks to a quite subordinate position in comparison 

 with selection, in the same manner as the sha})e of each 

 fragment used by our sujiposed architect is unimjxjitant 

 in comparison with his skill" ( Variation, xxi. ]h 301). 



It is quite possible that Darwin may be right in at- 

 tributing the modification and adajitation of oi'ganisms 

 almost entirely to the influence of natural selection, 

 and, at the same time, Avrong in his belief that the vari- 

 ations are fortuitous. Several critics have pointed out 

 that if it is true that variations have no relation wliat- 

 ever to the needs of the organism, there are grave diffi- 

 culties in the way of natural selection; but the tlicory 

 rests upon too firm a basis to be easily set aside, and 

 these objections have hardly received tlie attention 

 which they fairly deserve, for those authors who have 

 pointed them out have, at the same time, attacked the 

 general theory in a hostile spirit without projoosing any- 



