68 AGRICULTURE 



"work up into organic compounds, this free 

 ^nitrogen, and afterwards hand it on to the 

 plants on which the colonies have established 

 themselves. This association of two organ- 

 isms for the mutual benefit of both is not 

 uncommon both amongst plants and animals. 

 In the case we are considering the legu- 

 minous plant offers, as it were, house-room 

 to the bacteria, which, in return for the 

 . accommodation thus provided, convert 

 .* the free nitrogen into such a form that it 

 *si can be appropriated by the higher plant. 



Without these colonies of bacteria the 

 -Leguminosae are practically as helpless with 

 vregard to nitrogen as any other plants. 

 Ht has been asserted that it is a matter of 

 chance whether any particular leguminous 

 plant shall come into contact in the soil 

 with its appropriate organism, and it has 

 /been suggested that fields intended for the 

 growth of a leguminous crop should be 

 "inoculated" with a culture of the organ- 

 ism which can best enter into association 

 swith the particular crop that it is intended 

 tto grow. Various so-called cultures have 

 from time to time, during the past ten to 

 fifteen years, been put upon the market, and 

 farmers and gardeners have been led to 

 expect great results from their use. But in 



