THE WORK OF INSECTS. 137 



it is ill common tillage ; aud the roots in the one 

 must extend much further than in the other to 

 reach an equal quantity of nourishment ; they must 

 fill above twenty times the space to collect the 

 requisite amount of food." 



The part which insects perform in the pulveriza- 

 tion of the soil is often overlooked. White, in his 

 " Natural History of Selborne," remarks upon this 

 subject : " The most insignificant insects and rep- 

 tiles are of much more consequence, and have a 

 greater influence in the economy of nature, than 

 the incurious are aware of. They are mighty in 

 their efi'ects, from their numbers and fecundity, as 

 well as from that minuteness which renders them 

 so little an object of attention. Earth-worms, though 

 in appearance a small and despicable link in the 

 chain of nature, would, if lost, make a lamentable 

 chasm. To make no mention of the birds and 

 quadrupeds which are supported by them, worms 

 are great promoters of vegetation, by boring, perfo- 

 rating, and loosening the soil, and rendering it 

 pervious to the rain and fibers of plants, by drawing 

 straws, and stalks of leaves and twigs into it ; they 

 also throw up an infinite number of lumps of earth, 

 called worm-casts, which, being their excrement, is 

 a fine manure for grass and grain. Worms also 

 probably provide new soil for hills and slopes when 

 the rain has washed the earth away. Gardeners 

 and farmers often express their detestation of worms ; 

 12* 



