234 The Great World's Farm 



this, in the case of buildings, is provided first, probably, 

 by the decay of lichens and mosses and of the stone itself, 

 and also by the wind, which conveys many a little pile of 

 dust into sheltered nooks and corners. As for the mistle- 

 toe, being a parasite and living by the labor of others, it 

 has no difficulty about soil, and makes itself at home not 

 only on the oak, but on other trees, above all on the 

 apple. 



The fruit-eating, and consequently seed-carrying, birds 

 of the tropics are the countless multitudes of the parrot 

 tribe, which usually feed in flocks of thousands, and wander 

 far in search of food; and besides these, there are many 

 fruit-eating pigeons, hornbills, and others. Nor must 

 the immense flocks of large fruit-bats, or flying foxes, be 

 overlooked; for their numbers are so enormous that they 

 often take hours to pass, while their depredations in the 

 orchards are carried to such an extent as to make them 

 one of the greatest pests of the tropical fruit-grower of 

 the East. In his absence, however, the fruit-eaters have 

 done, and do, much valuable service in the way of carry- 

 ing seeds. 



Seed cannot be sown to any purpose until it is ripe, 

 and it would therefore be simply wasted if the birds 

 carrfed it off too soon. But it is safe enough from them 

 while it is unripe, for the eatable part, the flesh surround- 

 ing the seed, is unripe, too, as the birds very weU know, 

 and they leave it severely alone. 



Red, yellow, purple, and black are the most usual 

 colors of ripe fruit, and these the birds seem, therefore, 

 to understand best; for they seldom touch white currants 

 till the red are gone, though the white are the sweeter of 



