7 6 Field- L abourers 



or five to perhaps twelve inches, but no matter what 

 the nature of the soil beneath, there it is. One may 

 see it in any railway cutting, or on the top of any bank, 

 be it chalk or be it sand ; and this black earth, or 

 humus, is, to a very large extent, the work of worms. 



In a very loose soil worms can move easily, but, 

 generally speaking, as their bodies are soft, and cannot 

 pierce through anything at all hard or close, and, as 

 they have nothing but their mouths to work with, 

 they are obliged to eat their way through the ground. 

 No doubt they are fed, to some extent, by the animal 

 or vegetable matter contained in the soil, but their 

 primary object in swallowing it does not seem to be 

 food ; to swallow it is the only way they have of 

 getting rid of it, and their real object is to make a tube 

 or burrow in which to live. 



Where other food is scarce, or absent, they must, 

 of course, live on what they can get from the soil, and, 

 in purely mineral soils, they are rare accordingly, as 

 they could not find sufficient nourishment in it in case 

 of necessity. 



The effect produced upon the soil by its passage 

 through their bodies is very marked : it is not only 

 rendered extremely fine, but its colour is gradually 

 altered, becoming darker and darker, until, after re- 

 peated swallowing, it is turned almost black. The 

 layer of dark mould which covers our fields is dark just 

 because it is composed of the castings of worms, 

 castings which have passed through their bodies over 

 and over again, times innumerable. 



The worm has no teeth, and its mouth is a mere 

 opening, but it has the power of flattening its head and 

 extending it on each side of this opening so as to form 



