How Theories are Manufactured 79 



the autumnal and vernal equinox to roost in large com- 

 panies elsewhere, though for a short period ere the 

 winter thoroughly sets in, they will come back and 

 occupy themselves for some days in doing nothing 

 about their properties. The Cuckoo will open his lay 

 in April, and alter it in June, as the old rhyme promises, 

 and will play his singular role up and down the wood- 

 lands and meadows, giving Hedge-Sparrows and Pipits 

 the charge of his offspring, which they will, as a matter 

 of course, fatuously accept. The Gold-crest will weave 

 his pendent nest with the same superlative art as he 

 has ever done. The Bottle-tit will elaborate his poke- 

 pudding of a structure, and contrive to bring his dozen 

 or more of youngsters out of it with their long tails all 

 unruffled. The Willow-wren will build a domed nest on 

 the ground, and the Jenny-wren a domed nest above it. 

 The Thrush will plaster the inside of his, while Black- 

 caps will entrust eggs to so loose and light a structure 

 as to make it seem inevitable that they will fall through, 

 which, however, they will not. Swallows and Wagtails 

 will mob approaching Hawks. Wild-ducks will be fas- 

 cinated by the sight of a dog. All this and indefinitely 

 more may be set down beforehand, and set down in the 

 confident expectation of finding it performed. It is 

 quite clear that the actors are cast for their various 

 parts, and that somehow or other they have got those 

 parts by heart, and have no notion of anything but duly 

 going through them. And as it is clear that they do 

 not improvise for themselves as the piece goes on, any 

 more than they pick and choose, like ^Esop's Jackdaw, 

 what plumes they are to wear, men naturally set them- 

 selves to ask who or what it is that pulls the strings to 

 which these multitudinous figures move. 



This question scientific writers of the present day, or 

 rather, perhaps, writers on scientific subjects, undertake 

 with effusion to answer; and some of them are never 

 weary of telling us how exceedingly simple a thing an 

 answer is, since what they call the "illuminating" 

 doctrine of evolution has been given to the world. But 



