84 ANIMAL LIFE AND HUMAN PROGRESS 



on the same line of thought when he showed in his Newly 

 Discovered Secret of Nature (1793) the intertwining of the lives 

 of flowering plants and their pollinating insect - visitors. 

 Many naturalists have had glimpses of the system of inter- 

 relations, but it was Darwin who first discerned its subtlety 

 and evolutionary importance and made the idea of the web 

 of life germinal. 



To vivify the conception of the web of life, and man's share 

 in it, it is useful to think of particular types. Thus in his study 

 of the work of earthworms Darwin showed how many other 

 circles of life their life intersects. They make the earth 

 suitable for plants and for man's agricultural operations ; 

 they bring bacteria for good and ill to the surface ; they plant 

 trees ; they are preyed upon by carnivorous beetles, centipedes, 

 birds, moles and so forth. Similarly, if we take white ants or 

 termites, how many other circles their life-circle cuts. They 

 prune trees and make alluvial soil ; they grow fungi on laby- 

 rinthine beds and keep guest-beetles with a narcotic exudation ; 

 they wage war on true ants and are preyed upon by ant-eating 

 mammals, birds and reptiles; they hinder the spread of civilisa- 

 tion by destroying posts and boxes, furniture and books. 

 There are places, they say, where it is dangerous for a man 

 with a wooden leg to go to sleep without special precautions. 



Just as there is a correlation of organs in the body, the 

 various parts being members one of another, so there is a 

 correlation of organisms in the economy of Nature. Every one 

 knows Darwin's cats and clover story, and how he once got 

 eighty seeds to germinate from one clodlet from a bird's foot. 

 A sparrow cannot fall to the ground without sending a throb 

 through a wide circle. In the poet's fine hyperbole : " Thou 

 canst not stir a flower without troubling of a star." There is 

 a beautiful correlation between the amount of sunshine in 

 spring and the supply of mackerel at Billingsgate. For as all 

 flesh is grass, so all fish is infusorian and diatom and sea-grass. 

 As Shelley wrote : 



Nothing in this world is single ; 

 All things by a law Divine 

 In each other's being mingle ! 



