EVE AND PETRO 



the flies a colony of swallows could catch were alive to 

 pester his herd; for the happier and more comfortable 

 these animals are, the healthier they are and the more 

 milk they give. 



The hunting flights of Eve and Petro and their com- 

 rades lasted about fifteen minutes each time they took a 

 recess from their building. 



After two days the nest was big enough, so that there 

 was room for both swallows to build at once; and after 

 that, Petro did n^t have to fly around with his mouth full 

 of plaster waiting for Eve to go if he chanced to come 

 before she was through. They always chatted a bit and 

 then wxnt on with their work, placing their plaster care- 

 fully and bunting it smooth on the inside, modeling with 

 clay a house as well suited to their needs as is the con- 

 crete mansion a human architect makes suited to the 

 needs of man. 



And if you think it is a simple matter to make a nest 

 of clay, just go to the wisest architect you know and ask 

 him these questions. How many hodfuls of clay, each 

 holding as much as half a thimble, would it take to build 

 the wall of a room just the right shape for a swallow to 

 sit in while she brooded her eggs? How large would it 

 have to be inside, to hold four or five young swallows 

 grown big enough for their first flight? How thick would 

 the walls have to be to make it strong enough? What 



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