Chap. III. ANNUALLY ACCUMULATED. 175 



mingle the whole with vegetable debris, and 

 to saturate it with their intestinal secretions. 



Finally, no one who considers the facts 

 given in this chapter — on the burying of 

 small objects and on the sinking of great 

 stones left on the surface — on the vast 

 number of worms which live within a 

 moderate extent of ground — on the weight of 

 the castings ejected from the mouth of the 

 same burrow — on the weight of all the cast- 

 ings ejected within a known time on a measured 

 space — ^will hereafter, as I believe, doubt that 

 worms play an important part in nature. 



