30 



THE SOILS OF IRELAND. 



farmers yet fully realise the gain which would accrue from giving clovers and 

 other leguminous crops a larger place in their rotations. It is now well 

 known that such crops have the peculiar faculty of appropriating, through 

 the agency of micro-organisms (which generally inhabit soils, and colonize 

 in warts upon the roots of leguminous plants), free nitrogen, which exists in 

 the atmosphere in unlimited quantities, and finds its way into the pores of 



Specimens of Clover Plants ; the larger plant exhibiting Root Warts. 



the soil. The accompanying illustration* shows two clover plants : one 

 grown in soil devoid of micro-organisms, the other, of much larger size, 

 under the same circumstances of cultivation, grown in soil to which micro- 

 organic earth had been added. The latter exhibits the root warts, which 

 formed at once the abodes and laboratories of the microscopic beings. 



The saving to the farmer's purse, in a lessened necessity for the purchase 



* Reproduced from Salfeld's " Bodcnimp/uiig," with the permission of Dr. Salfeld's publisher, 

 M. Heinsius Nachfolger, of Leipzig. 



