56 DARWINISM AND HUMAN LIFE 



are the agents in passing the plague-germs to 

 man. 



Far-eeaching Influence op certain Animals : 

 Earthworms. — We realise the idea of the web 

 of life in another way when we consider the 

 far-reaching influence of particular kinds of acti- 

 vity, the best instance being the work of earth- 

 worms. In 1777 Gilbert White got at the very 

 root of the matter. " The most insignificant 

 insects and reptiles are of much more consequence 

 and have much more influence in the economy 

 of nature than the incurious are aware of. . . . 

 Earthworms, though in appearance a small and 

 despicable link in the chain of nature, yet, if 

 lost, would make a lamentable chasm. . . . 

 W^orms seem to be the great promoters of vege- 

 tation, which would proceed but lamely without 

 them, by boring, perforating, and loosening the 

 soil, and rendering it pervious to rains and the 

 fibres of plants ; by drawing straws and stallis 

 of leaves and twigs into it ; and, most of all, 

 by throwing up such infinite numbers of lumps 

 of earth called worm-casts, which, being their 

 excrement, is a fine manure for grain and grass. 

 Worms probably provide new soil for hills and 

 slopes where the rain washes the earth away ; and 

 they affect slopes probably to avoid being flooded. 

 . . . The earth without worms would soon become 

 cold, hard-bound, and void of fermentation, and 

 consequently sterile. . . . These hints we think 

 proper to throw out, in order to set the inquisitive 

 and discerning at work. A good monograph of 

 worms would afford much entertainment and 

 information at the same time, and would open a 

 large and tx&w field in natural history," 



