Economy of Energy 



This does not mean that the primitive art 

 has disappeared, lost through neglect; it re- 

 mains an ineffaceable characteristic of the 

 species, ever ready to declare itself should 

 circumstances demand it. The generations of 

 to-day are as much endowed with it as the 

 generations of yore; without apprenticeship, 

 without the example of others, they have 

 within themselves, in the potential state, the 

 industrial aptitude of their ancestors. If 

 aroused by the stimulus of necessity, this apti- 

 tude will pass suddenly from inaction to ac- 

 tion. When, therefore, the Sparrow still 

 from time to time indulges in spherical build- 

 ing, this is not progress on his part, as is some- 

 times contended; it is, on the contrary, a retro- 

 gression, a return to the ancient customs, so 

 prodigal of labour. He is behaving like the 

 Osmia who, in default of a reed, makes shift 

 with a Snail-shell, which is more difficult to 

 utilize but easier to find. The cylinder and 

 the hole in the wall stand for progress; the 

 spiral of the Snail-shell and the ball-shaped 

 nest represent the starting-point. 



T have, T think, sufficiently illustrated the 

 inference which is borne out by the whole 

 mass of analogous facts. Animal industry 



231 



