THE EARTHWORM IN NATURE 35 



Working through remote geological ages down to the present 

 in practically unchanged form, the earthworm has been and is 

 one of the great integrating, soil-building forces of nature. In 

 this movement of "rock material on its way to the deep," all life, 

 both vegetable and animal, has contributed to make the subsoil 

 and topsoil the great repository of the physical elements of life 

 oxygen, nitrogen, calcium, phosphorus, potassium, sodium, mag- 

 nesium, sulphur, silicon, hydrogen, chlorine, iron, with traces of 

 practically all the known elements of the universe. In, the build- 

 ing of this repository, the earthworm has contributed a major 

 part, for practically all of the fertile topsoil of earth's surface 

 has passed many times through the bodies of earthworms. 



In the book Man and the Earth, the noted Harvard geologist, 

 Nathaniel Southgate Shaler, has aptly called the thin layer of 

 humus-bearing topsoil "the placenta of life." Continuing, Shaler 

 warns : "Man and all forms of life draw life from the sun, clouds, 

 air, and earth through a tenuous film of topsoil, indispensable 

 and, if rudely handled, impermanent." In the continual renewal 

 and maintenance of this important surface layer upon which life 

 depends, the earthworm is one of the greatest tools of nature. 



Animal life in all its forms, from microbe to man, is the 

 great transformer of vegetation into perfect earthworm food, the 

 animal life itself, in the end, becoming food for the earthworm. 

 In the process of transformation, a small percentage becomes ani- 

 mal tissue, but most of it becomes food for humus-building 

 worms. In the feeding of 100 pounds. of grain to domestic ani- 

 mals, such as cattle, sheep and hogs, on the average 89^ pounds 

 becomes excrement, waste and gases, with only 10^ pounds ac- 

 counted for by increase in animal weight. Aside from the gaseous 

 waste, the 89^2 pounds represents earthworm food. In a never- 

 ending annual cycle untold millions of tons of the products of 

 forest and farm, orchard and garden, rivers, lakes, and oceans, 

 are harvested, to be transformed into earthworm food after they 

 have nourished animal life and served man. All the biological 

 end-products of life kitchen and farm waste, stubble, dead vege- 



