THE WEB OF LIFE 59 



the idea of which is essential to an understanding 

 of the struggle for existence and natural selection. 

 But it also illustrates what, Darwin had learned 

 from Lyell — that great results may be brought 

 about by the accumulation of infinitesimal items. 

 As Prof. A. Milnes Marshall said : " The lesson 

 to be derived from Darwin's life and work cannot 

 be better expressed than as the cumulative import- 

 ance of infinitely little things." 



Termites, or White Ants. — ^Henry Drummond, 

 in his " Tropical Africa," tried to make out a case 

 for the agricultural importance of termites, or 

 white ants. It is well known that these old- 

 fashioned insects have a pruning action in the 

 forest, destroying dead wood with great rapidity. 

 Houses and furniture, fences and boxes, as well 

 as forest-trees, fall imder their jaws. In some 

 places, " if a man lay down to sleep with a wooden 

 leg, it would be a heap of sawdust in the morning." 

 But what of the termites' agricultural importance ? 

 The point is that they keep the soil circulating 

 by constructing earthen tunnels up the sides of 

 trees and posts and by making huge obehsk-Uke 

 ant-hills, or termitaries. " 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." It must be noted, however, 

 that Drummond did not prove his case with suffi- 

 cient precision, and there is, as Escherich points 

 out in his beautiful study of termites,^ this difficulty, 

 that, while the castings of earthworms are soft 

 and loose, the earth-tubes and constructions of 

 termites are stony. 



I " Die Termiten." (Leipzig, 1909.) 



