CHAP. II The Web of Life 25 



The influences of plants and animals on the earth are 

 manifold. The sea- weeds cling around the shores and 

 lessen the shock of the breakers. The lichens eat slowly 

 into the stones, sending their fine threads beneath the sur- 

 face as thickly sometimes " as grass-roots in a meadow-land," 

 so that the skin of the rock is gradually weathered away. 

 On the moor the mosses form huge sponges, which mitigate 

 floods and keep the streams flowing in days of drought. 

 Many little plants smooth away the wrinkles on the earth's 

 face, and adorn her wdth jewels ; others have caught and 

 stored the sunshine, hidden its power in strange guise in 

 the earth, and our hearths with their smouldering peat or 

 glowing coal are warmed by the sunlight of ancient summers. 

 The grass which began to grow in comparatively modern 

 {i.e. Tertiar)^) times has made the earth a fit home for flocks 

 and herds, and protects it like a garment ; the forests affect 

 the rainfall and temper the climate, besides sheltering multi- 

 tudes of living things, to some of whom everj' blow of the 

 axe is a death-knell. Indeed, no plant from Bacterium to 

 oak tree either lives or dies to itself, or is without its 

 influence on earth and beast and man. 



There are many animals besides worms which influence 

 the earth by no means slightly. Thus, to take the minus 

 side of the account first, we see the crayfish and their 

 enemies the water-voles burrowing by the river banks and 

 doing no little damage to the land, assisting in that process 

 by which the surface of continents tends gradually to 

 diminish. So along the shores in the harder substance 

 of the rocks there are numerous borers, like the Pholad 

 bivalves, whose work of disintegration is individually slight, 

 but in sum-total great. More conspicuous, however, is the 

 work of the beavers, who, by cutting down trees, building 

 dams, digging canals, have cleared away forests, flooded 

 low grounds, and changed the aspect of even large tracts 

 of country. Then, as every one knows, there are injuri- 

 ous insects innumerable, whose influence on vegetation, on 

 other animals, and on the prosperity of nations, is often 

 disastrously great. 



But, on the other hand, animals cease not to pay their 



