NITROGEN-GATHERING BACTERIA. 147 



nature's rotation of crops. The legumes exist, their bac- 

 teria store the priceless nitrogen, the earth is enriched 

 thereby, and all manner of pleasant grains and grasses 

 and fruits follow, feeding on this store of nitrogen gath- 

 ered mainly by the legumes and their allies, the bacteria. 



Other Nitrogen-Gathering Bacteria. There seem 

 other bacteria, not inhabiting legumes, that can in some 

 manner store nitrogen. These are found in soils fairly 

 well filled with vegetable matter. In old pasture sods are 

 found the azotobacter bacteria, most beneficent organisms, 

 storing fertility as they live on decaying leaves, roots and 

 stems. There seem no helpful bacteria in any soils devoid 

 of humus or legumes. 



Lessons that All May Read. See that field of oats with 

 the sharply-outlined line of dark, rich green? On the 

 part growing so rankly stood alfalfa or clover. The 

 chances are there is now too much nitrogen there for the 

 oats, and they will likely lodge. Corn should have been 

 planted instead ; it stands stiff no matter how big it grows 

 and no soils are too rich for it. In California on alfalfa 

 fields, orchards and orange groves have shown the effect 

 of having been planted on alfalfa fields years after the 

 alfalfa roots had crumbled to mould. 



Value of Legumes. Chemical analysis shows legumin- 

 ous plants to be rich in protein. Protein makes red flesh, 

 blood, milk and brain tissue. Most feed-stuffs are poor 

 in protein ; legumes come in to balance the excess of car- 

 bohydrates in the grasses and grains. Thus timothy hay 

 is too poor in bone and muscle-making material, properly 

 to nourish animals; a portion of clover or alfalfa mixed 



