THE ASCENDING SAP 



101 



the end of four years, ea.ch part of the soil will have had each kind of 

 plant growing on it, and the order for the four years will stand thus : 



In former times it was a usual thing to give rest to the land by allowing 

 it to lie fallow at certain intervals, and though our scientific agriculturists 

 have now discovered other means of replenishing the soil, the practice has 

 by no means died out. 



The importance of this sys- 

 tem of fallowing was known 

 to the ancients, for Virgil in 

 his first Georgic mentions it, 

 and suggests as an alternative 

 that the husbandmen should 

 follow the Barley crop by sow- 

 ing leguminous plants, thus 

 anticipating, or at least fore- 

 shadowing, the very modern 

 discovery of the nitrification 

 of the soil by the roots of 

 these plants, or rather by the 

 bacteria that attach them- 

 selves thereto. He says: 

 " You shall sow the golden 

 Barley whence formerly you 

 had borne away the luxuriant 

 Pulse in their rattling pods, 

 or the slender produce of the 

 Vetch, or the bitter Lupin's 

 fragile stalks and rattling 

 straw." 



It is remarkable that to the 

 present day the Germans 

 grow Lupins on very poor 

 land every third or fourth 

 year, solely for the purpose 



Of ploughing them in for the 



nf fVio enil anrl 

 OI tne SOU and 



FlG ' ^ 



( Dr080 P h y llum 



A sub-shrubby plant of the Peninsula and Xorth Africa. The ten- 



tacles do not close over their prey, as in the Sundew. The natives 



hang these plants in their rooms in lieu of fly-papers. 



