120 NATURAL SELECTION vi 



nests of many of the swifts and swallows, as well as that of 

 the song-thrush peculiarities of habits which ultimately 

 depend on structure, and which often determine the material 

 most frequently met with or most easily to be obtained. 

 Modifications in any of these characters would necessarily 

 lead either to a change in the materials of the nest, or in the 

 mode of combining them in the finished structure, or in the 

 form or position of that structure. 



During all these changes, however, certain specialities of 

 nest-building would continue for a shorter or a longer time 

 after the causes which had necessitated them had passed 

 away. Such records of a vanished past meet us everywhere, 

 even in man's works, notwithstanding his boasted reason. 

 Not only are the main features of Greek architecture mere 

 reproductions in stone of what were originally parts of a 

 wooden building, but our modern copyists of Gothic archi- 

 tecture often build solid buttresses capped with weighty 

 pinnacles to support a wooden roof which has no outward 

 thrust to render them necessary; and even think they 

 ornament their buildings by adding sham spouts of carved 

 stone, while modern waterpipes, stuck on without any attempt 

 at harmony, do the real duty. So, when railways superseded 

 coaches, it was thought necessary to build the first-class 

 carriages to imitate a number of coach-bodies joined together; 

 and the arm-loops for each passenger to hold on by, which 

 were useful when bad roads made every journey a succession 

 of jolts and lurches, were continued on our smooth macadam- 

 ised mail-routes, and, still more absurdly, remain to this day J 

 in our railway carriages, the relic of a kind of locomotion we 

 can now hardly realise. Another good example is to be seen 

 in our boots. When elastic sides came into fashion Ave had 

 been so long used to fasten them with buttons or laces, that 

 a boot without either looked bare and unfinished, and accord- 

 ingly the makers often put on a row of useless buttons or 

 imitation laces, because habit rendered the appearance of 

 them necessary to us. It is universally admitted that the 

 habits of children and of savages give us the best clue to the 

 habits and mode of thought of animals ; and every one must 

 have observed how children at first imitate the actions of 

 1 Since this was written they have generally been disused. 



