24 THE STUDY OF ANIMAL LIFE CHAP. 



to throw out, in order to set the inquisitive and discerning to work. 

 A good monograph of worms would afford much entertainment 

 and information at the same time, and would open a large and 

 new field in natural history." 



After a while the discerning did go to work, and Hen- 

 sen published an important memoir in 1877, while 

 Darwin's " good monograph " on the formation of vege- 

 table mould appeared after about thirty years' observation 

 in 1881 ; and now we all say with him, ' It may be 

 doubted whether there are many other animals which 

 have played so important a part in the history of the 

 world as have these lowly-organised creatures." 



Prof. Drummond, while admitting the supreme import- 

 ance of the work of earthworms, sought to emphasise the 

 claims of the Termite or White Ant as an agricultural 

 agent. This insect, which made its appearance long 

 before the true ants, is abundant in many countries, and 

 notably in Tropical Africa. It ravages dead wood with 

 great rapidity. " If a man lay down to sleep with a 

 wooden leg, it would be a heap of sawdust in the morn- 

 ing," while houses and decaying forest trees, furniture 

 and fences, fall under the jaws of the hungry Termites. 

 These fell workers are often quite blind ; they are 

 typically " cryptozoic," avoiding the light ; and yet 

 without coming out of the ground they cannot live. 



" How do they solve the difficulty ? They take the ground out 

 along with them. I have seen white ants working on the top of a 

 high tree, and yet they were underground. They took up some of 

 the ground with them to the tree-top. They construct tunnels 

 which run from beneath the soil up the sides of trees and posts ; 

 grain after grain is carried from beneath and mortared with a sticky 

 secretion into a reddish sandpaper-like tube ; this is rapidly ex- 

 tended to a great height even of 30 feet from the ground till 

 some dead branch is reached. Now as many trees in a forest are 

 thus plastered with tunnels, and as there are besides elaborate 

 subterranean galleries and huge obelisk-like ant-hills, sometimes 

 10-15 feet high, it must be granted that the Termites, like the 

 earthworms, keep the soil circulating. The earth-tubes crumble 

 to dust, which is scattered by the wind ; the rains lash the forests 

 and soils with fury and -wash off the loosened grains to swell the 

 alluvium of a distant valley." 



The influences of plants and animals on the earth are 



