586 THE WONDER OF LIFE 



product the creation-result of the germ-plasm with its 

 great uniformity and yet ever-newness, and the environ- 

 ment with its great uniformity and yet ever-newness. 

 The germ-plasm is variable, that is to say it makes experi- 

 ments, some futile, like every artist's, some successful. 

 Those that are successful are so because their urgent fingers 

 fit into the environmental glove. But this metaphor is on 

 one side too static. For the germinal experiments that 

 succeed are those to which the environment offers, as it 

 were, encouraging opportunity for expression. 



Tactics of Nature. What we have said in regard to 

 the method of organic evolution refers only to the general 

 formula, and we cannot here do more than illustrate the 

 answers to the interesting further question that arises as 

 to the detailed tactics in particular cases. The production 

 of such geniuses as ants and bees, wasps and spiders, rooks 

 and cranes, elephants and horses, remains more or less 

 of a mystery. Though in some cases, such as elephants and 

 horses, we have considerable information as to the historical 

 stages of evolution, we have little light in regard to the 

 organic urge which may have accounted for the successive 

 uplifts. As has been said, we understand the survival 

 but not the arrival of mutations. It is different, however, 

 when we turn to Nature's method of making extraordinarily 

 new things out of very old things. For this is what has 

 happened in a great number of cases where something 

 apparently novel has emerged. The old is, as it were, re- 

 crystallized. The mineral becomes a jewel. Let us give 

 a few illustrations. 



The spinnerets of a spider are very novel contrivances, 

 but they apparently represent transformed limbs. The 

 butterfly's spiral proboscis is a coiled jaw and the bee's 



