152 LIFE OF 



In concluding, the author enforces the claims of 

 worms on the gratitude of archaeologists, as they protect 

 and preserve for an indefinitely long period every object 

 not liable to decay which is dropped on the surface of 

 the land, by burying it beneath their castings. It is thus 

 that many tesselated pavements and other ancient 

 remains have been preserved; but, on the other hand, 

 worms have undermined many old massive walls and 

 caused them to subside, and no building is in this 

 respect safe unless the foundations are at least six or 

 seven feet beneath the surface, below which depth worms 

 cannot work. Worms also prepare the ground in an 

 excellent manner for plant life, periodically exposing the 

 mould to the air, sifting it so that no stones larger than 

 the particles they can swallow are left in it, mingling the 

 whole intimately together, burying all decaying objects 

 within reach of the roots of the plants, allowing air to 

 penetrate deeply into the earth. "When we behold a 

 wide, turf-covered expanse, we should remember that its 

 smoothness, on which so much of its beauty depends, is 

 mainly due to all the inequalities having been slowly 

 levelled by worms. It is a marvellous reflection that the 

 whole of the superficial mould over any such expanse 

 has passed, and will again pass, every few years through 

 the bodies of worms. The plough is one of the most 

 ancient and most valuable of man's inventions ; but long 

 before he existed the land was in fact regularly ploughed, 

 and still continues to be thus ploughed by earthworms. 

 It may be doubted whether there are many other animals 

 which have played so important a part in the history 

 of the world, as have these lowly organised creatures." 



