THE SOILS THAT LIVING THINGS HAVE MADE 21 



advanced when animals first made their appearance. But 

 animals of all sorts have been potent workers in soil 

 making-, the higher animals largely by the manurial re- 

 turn to the land and the lower forms through the manurial 

 effect, but also in directly affecting the physical conforma- 

 tion of earth. 



For does not the ant seek the earth for its home and 

 shelter, to construct there its house of many rooms, with 

 the many tunnels connecting the dwellings of the nation? 

 What are these homes and these tunnels but underground 

 traps for air and moisture soil builders? 



Besides the work done in this direction, a tremendous 

 quantity of earth is annually turned over and exposed to 

 sunshine and rain, to heat and cold, to every influence 

 concerned with soil making and soil improvement. 



Every sort of insect or animal that burrows into the 

 soil, that opens it, or tunnels it, or loosens it, contributes 

 not a little to soil making: the ant that builds there, the 

 mole that tunnels, the prairie dog or hedgehog that bur- 

 rows, the earthworm that glides and crawls, and even 

 eats and digests all are man's good friends in having had 

 a hand in preparing the surface of the earth for the luxuri- 

 ant growth of vegetable life. 



The task of the earthworm. The task that has been 

 the earthworm's is a most important one. So simple are 

 these creatures, so faithful are they in their labors, so 

 undemonstrative in their duties, we scarcely give them a 

 thought save the time when we seek them for bait for our 

 fishing traps. But the earthworm has for ages been 

 busy opening the soil to air and water, and even more : it 

 eats the raw soil underground and plows its way upwards 

 and downwards, casting at the surface the unused por- 

 tions of its eatings. In doing this, the muscular gizzard 

 of the worm is ever busy rubbing and grinding stony 



