Experiments in Inoculation 225 



very gratifying results. Incidentally, the observation 

 was made that in a mixture of field-peas and lupins, 

 seeded on the same soil, the former developed numerous 

 nodules, while the latter possessed scarcely any nodules 

 at all, an indication that the same organism is not capa- 

 ble of producing nodules on both peas and lupins. 



Altogether, these early experiments with old legume- 

 soil as inoculating material demonstrated the usefulness 

 of soil-inoculation under certain conditions. They also 

 rendered another service to agriculture in calling at- 

 tention to the need of careful preparation of the soil 

 for the best development of legumes, of the importance 

 in this respect of humus, lime and of phosphoric acid 

 and potash. They helped to spread gradually the know- 

 ledge that leguminous plants are different from those of 

 other families. They helped to make plain, also, that 

 their power of gathering atmospheric nitrogen as de- 

 termined by their relation with the bacteria in their 

 nodules was capable of being modified by soil conditions. 

 Intelligent farmers came to know that soil-inoculation 

 meant simply the transfer of bacteria from one soil to 

 another. They learned, also, that different soils were not 

 equally efficient for the purpose, some of them contain- 

 ing, apparently, more vigorous organisms than the others. 



Certain observations were made, likewise, in the use 

 of legume-earth. Under certain conditions it was seen 

 that its application was objectionable even where it was 

 desired to introduce bacteria in the soil. Instances were 

 noted in which soil-transfer from one field to another 

 led to the introduction of weeds and to fungous troubles. 

 Our own experience in this country in the inoculation of 



