198 THE BOOK OF ALFALFA 



hailed as one of the greatest of the age. With milHons 

 of pounds of nitrogen over his land there seemed now a 

 method whereby the farmer could utilize some needed 

 portions of it. The bacteria live in tubercles upon the 

 roots of various leguminous plants, such as Red clover, 

 Sweet clover, Bur clover, alfalfa, cowpeas, garden peas, 

 vetches and beans. These tubercles are the home of the 

 bacteria, minute forms of vegetable life, too small to be 

 seen with the naked eye. The legumes have no power in 

 themselves to draw nitrogen from the air, yet these bac- 

 teria seem to have the power to absorb the free nitrogen 

 and cause it to combine with other elements, forming 

 nitrates or other assimilable compounds suitable for 

 plant food. It has also been demonstrated that, as a rule, 

 there are different species of these bacteria for different 

 species of legumes. 



After German scientists had made their discoveries, 

 one of the existence of these bacteria on the roots of the 

 legumes and another that in the laboratory, these organ- 

 isms could be bred and multiplied, they seemed unable to 

 develop them of sufficient vigor to survive any general 

 distribution. At this point Dr. George T. Moore of the 

 United States Department of Agriculture, hit upon a plan 

 of cultivating them in a way by which they could be pre- 

 served for many months, and he also gave them a much 

 greater power. This nitrogen-fixing power was so devel- 

 oped that seeds soaked in the solution, it is claimed, 

 sprouted and produced plants in sand that possessed no 

 nitrates. He then found that these bacteria when grown 

 upon nitrogen-free media will retain a high activity for a 

 long time, if carefully dried out and then revived in a 



