THE EARTHWORM IN SCIENTIFIC LITERATURE 41 



at the time the numbers were estimated in July, in the upper foot 

 of soil." 



In a radio address delivered over WGY Farm Forum, Prof. 



Svend O. Heiberg of the New York State College of Forestry 



\said: "If your soil is suitable for earthworms . . . there may be 



I more than two and one-half million per acre, weighing about 



[1400 pounds. That means that you may have more pounds of 



earthworms in your employment than all your domestic animals 



put together." 



Mr. Arthur J. Mason, testifying as an expert before the 

 Committee on Flood Control, House of Representatives, Seven- 

 tieth Congress, stated: "The weight of the angleworms in this 

 country is at least tenfold the weight of the entire human popu- 

 lation." Mr. Mason estimated that the farm lands of Ilinois, 

 his home state, in normal circumstances contain an earthworm 

 population of more than six hundred billion. 



Hundreds of quotations from scientific literature could be 

 cited, corroborative of the foregoing, but it is unnecessary to bur- 

 den these pages with further examples. 



SOIL-BUILDERS OF FOREST LANDS 



Curtis Fletcher Marbut, noted soil scientist and for many 

 years Chief of the Soil Survey Division in the United States De- 

 partment of Agriculture, expressed the belief that in certain areas 

 the granular condition characterizing whole layers of soil is due 

 to earthworm casts. We quote from "Soils and Men," U. S. De- 

 partment of Agriculture Yearbook for 1938, page 946 : 



Certain mulls, or granular mixtures of mineral and organic 

 material produced by earthworms, give particular areas of the 

 forest floor their whole character. 



Quoting further from the same book in the chapter on 

 "Formation of Soil," pages 964-965, we find : 



Earthworms feed on soft* and organic matter and thoroughly 

 mix soils in which they live. They move and enrich many tons of 



