ii THE WEB OF LIFE 25 



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 

 surface 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 with 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. Tertiary) 

 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 every blow of 

 the axe is a death-knell. Indeed, no plant from Bac- 

 terium 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 sub- 

 stance of the rocks there are numerous borers, like the 

 Pholad bivalves, whose work of disintegration is indi- 

 vidually 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 r grounds, and changed the 

 aspect of even large tracts of country. Then, as every 

 one knows, there are injurious 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 

 filial debts. We see a multitudinous life rising like a 



