244 
INSTINCT. 
Chap. YII. 
any other known bird. Finally, it may not be a logical 
deduction, but to my imagination it is far more satisfac¬ 
tory to look at such instincts as the young cuckoo eject¬ 
ing its foster-brothers,—^ants making slaves,—the larvae 
of ichneumonidae feeding within the live bodies of cater¬ 
pillars,—not as specially endowed or created instincts, 
but as small consequences of one general law,, leading 
to the advancement of all organic beings, namely, mul¬ 
tiply, vary, let the strongest live and the weakest die. 
