Chap. YIJL] SUMMARY. 365 



known bird. Finally, it may not be a logical deduction, 

 but to my imagination it is far more satisfactory to look 

 at such instincts as the young cuckoo ejecting its foster- 

 brothers, — ants making slaves, — the larvae of ichneu- 

 monidae feeding within the live bodies of caterpillars, — 

 not as specially endowed or created instincts, but as 

 small consequences of one general law leading to the 

 advancement of all organic beings, — namely, multiply 

 vary, let the strongest live and the weakest die. 



THE E>!D OF VOL. I. 



