A Splendid Act of Reason. 173 



the young to force their way out, as in the young 

 cuckoos turning out the true young, to carry forward 

 the old one's deposition of eggs. Judging from ana- 

 logy, in none of these cases was this the first and 

 original nest of the bird ; but a nest that was at a 

 definite point hit on by these various species, to meet 

 enemies and to overcome difficulties that threatened 

 the very existence of the species. The truth is, all 

 these ingenious and resourceful nests are but proofs 

 of a process of high differentiation. 



Now, here you have something in which instinct, 

 however strong and however strange, could not, at 

 first, at all events, have aided these creatures. Once 

 these ingenious hang nests and mound nests were 

 made, of course, and had continued to be made for 

 generations, the making of them would in so far pass 

 into something more of mere hereditary gift, but cer- 

 tainly not that solely or absolutely. The species that 

 had individuals who could show such power of in- 

 vention, resource, and reasoning, in the process of 

 adapting structure of nests to needs due to changed 

 conditions ; and besides that, in the case of the 

 Leipoa, had made veritable heat do the work of sitt- 

 ing, so as to defy the powers and resources of enemies 

 threatening actually the existence of the species, had 

 within them, latent, the same powers, still to be 

 educed again in circumstances equally threatening 

 the existence of the class. The moment (and it is 

 inevitably the thing of one moment) of the passage 

 from an ordinary twig or branch-supported nest in a 

 tree, to a hang nest over the water, with an object, is 

 a moment that celebrates a splendid act of reason. 



The eggs of the Leipoa ocellata, again, are so fine 



