The Outline of Science 



Nutritive Linkages 



The system of Animate Nature involves nutritive chains, 

 one creature being dependent upon another for sustenance. Ani- 

 mals eat plants or other animals, or, in some cases, what plants 

 and animals have made, e.g. fallen leaves and stored honey. In 

 any case, there is a continual circulation of matter from one em- 

 bodiment to another. There is an endless cycle of incarnations. 

 The codfish eats the whelk, the whelk devours marine worms, 

 worms feed on the sea dust meaning by that the microscopic 

 organisms that swarm in the waters. A cartload of bracken is 

 tumbled into a loch; it is acted on by bacteria which break it 

 down into particles and simpler substances; on these and on the 

 bacteria themselves myriads of infusorians feed; these in turn 

 are devoured by small crustaceans, and these are devoured by 

 trout. It is very important for practical purposes to discover 

 these nutritive chains. 



The most insignificant plants and animals often play an 

 important part in the economy of nature, or what we call the 

 Balance of Life. Thus earthworms may seem to form a "despic- 

 able link in the chain of nature," yet they are all-important. 

 Vegetation would fare ill without them. How well Gilbert White 

 (1777) appreciated their importance! 



Earthworms, though in appearance a small and despic- 

 able link in the chain of Nature, yet, if lost, would make a 

 lamentable chasm. Worms seem to be the great promoters 

 of vegetation, which would proceed but lamely without them, 

 by boring, perforating, and loosening the soil, and render- 

 ing it pervious to rains and the fibres of plants, by drawing 

 straws and stalks into the soil; and most of all by throwing 

 up such infinite numbers of lumps of earth. . . . The earth 

 without worms would soon become cold, hard-bound, and 

 void of fermentation, and consequently sterile. 



When he was a young student in Edinburgh, Charles Dar- 

 win began studying the work of earthworms, counting the num- 



