Origin of Species Variorum

Comparison with 1872

any other 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 larvæ of ichneumonidæ 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.

any other 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 larvæ of ichneumonidæ 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.