OF AGRICULTURE. 209 



from the air thus fixing in the soil this important 

 stimulant, as well as nutritive ingredient ready to be 

 taken up by the rootlets of plants. 



When we consider the great importance of the 

 properties of " humus " just referred to, it cannot bo 

 surprising that its presence should, as a general rule, 

 exercise an influence so decidedly favorable on the 

 productiveness of soils, yet it is incontestably true 

 that "humus" alone, without mineral ingredients, 

 will not support vegetable growth. It is, neverthe- 

 less, true that a perfectly healthy growth of cereals 

 or any useful cultivated plant is rarely attained in 

 soils destitute of "humus/' Hence the necessity of 

 composting mineral ingredients with vegetable mold 

 or humus. [Professor E. W. Hilyard, West of Missis- 

 sippi. 



The mere presence of growing plants of roots, of 

 seeds where life is, impresses upon both the vegetable 

 and mineral elements of the soil power to enter into 

 new combinations. The soil then is not external to 

 plants; so far as life is concerned it is as much 

 internal as if the plant had a mouth and stomach 

 through and into which the soil might be fed. Call 

 this power life, electricity, galvanism or by any 

 other name, still the great fact remains, that the 

 mere presence of a living, growing plant in the soil 

 effects a greater amount of decomposition than all 

 the other influences. This fact is of the highest 

 importance in practical agriculture. 



It is this decomposing action of the living plant 

 on the mineral elements in the soil which affords the 

 only'reasonable explanation of the action of the salts 

 in agriculture. This power of life dissolves the 



