WORMS 



soil are first the leaf-mould of two years ago, then that of 

 the year before last, and on the top is the leaf-mould and 

 other decayed products of last winter. 



All these upper layers are full of life and activity, which 

 probably goes on vigorously all the year round. 



The population of worms is especially important. The 

 worm is a voracious and gluttonous creature : it is for ever 

 swallowing bits of leaves and rich soil. Inside its body 

 there are lime-glands which act upon the vegetable food and 

 improve its quality as manm-e. The worm comes up to the 

 surface at night or early morning and leaves the worm-casts 

 upon it. The rain then washes the rich, finely-divided 

 matter of the casts down into the soil again. It is said 

 that there are about 160,000 worms at work in an acre of 

 good soil. Yet their life is full of danger. A keen-eyed 

 population of blackbirds, thrushes, starlings, peewits (plover), 

 and partridges are always watching for and preying upon 

 the poor worm. Even in his burrows, which may be six feet 

 deep, he is not safe, for the mole (moudiewarp) is also both 

 very hungry and very active, and delights in eating him. 



In the soil also and even deeper in the subsoil are many 

 insects ; some hibernate in the winter, and at other times 

 actively gnaw the roots of plants or devour dead leaves and 

 twigs (see Chapter xxiii.). Thus there are many burrows and 

 holes, so that there is no want of air in the soil, which 

 is indeed necessary both for these creatures and also for the 

 roots of the plants. 



Rain comes down through the soil, carrying with it car- 

 bonic acid, mineral salts, and also germs or bacteria, which 

 form perhaps the most important population of all. 



No work could be carried on without their help ; it is 

 bacteria which, at every stage of decay, assist in breaking up 



85 



