8 2 TRA^'SACTIO^'S and proceedings of the [Sess. lxii. 



nitrogen in their roots, those without nodules had rather 

 more in their leaves. The nodules themselves contained 

 as much as -i'S per cent, of nitrogen. 



He also grew lupines in pots containing washed sand, to 

 which he added fertilising materials such as plants require, 

 in the form of a solution made perfectly sterile, and with 

 which the plants were watered, but in this nutritive solution 

 there was no nitrogenous matter. Moreover, the pots 

 were covered with wadding to protect them from infection 

 of any kind by means of air-borne spores. Ten lupine 

 plants thus grown assimilated from the air "lOl grams 

 nitrogen. These roots had no nodules. Ten lupine plants 

 treated in the same .way and grown in the same kind of 

 soil, to which a few grams of unsterilised lupine soil were 

 added so as to inoculate the earth, assimilated 1*575 grams 

 of air nitrogen, viz. about eight times as much as the others, 

 and their roots were well studded with nodules. So 

 much for the lupines grown in sterilised soil with and 

 without inoculation, and, consequently, with and without 

 nodules. 



He made a parallel experiment with lupines grown in 

 an unsterilised poor soil, consisting almost entirely of sand 

 dug out from several feet below the surface of tlie ground, 

 and almost destitute of organisms. They were treated with 

 the non-nitrogenous solution as the others, but the surface 

 of the soil in the pots was left exposed to the air. 



He inoculated one-half of the pots with a few grams of 

 lupine soil, and left the other half uninoculated. 



In the inoculated half the roots of the plant were well 

 grown with nodules. On the uninoculated half, only a few 

 imperfectly developed nodules appeared in several of the 

 pots. 



He selected ten plants from each division, viz. ten plants 

 with nodules, and ten plants witliout, but otlierwise well 

 grown, and analysed them, witli the result that there was 

 almost no difference in the amount of nitrogen the two lots 

 had assimilated from the air. As it happened, the un- 

 inoculated lot tliat had no nodules assimilated rather more 

 than the other. The quantities were — 



Without nodules . 2'126 grams nitrogen. 



With nodules . . 2-09 „ 



