6^8 



Inoculation of Leguminous Plants. [feb., 



cultures themselves, variations in which are quite sufficient to 

 account for the conflicting results obtained. The organism is 

 believed to be incapable of forming spores (the resting stage) 

 and the wonder is, not that so many of the American cultures 

 should have failed, but that the organism should have been 

 capable of living for so long on cotton-wool, as many of the 

 experiments have proved to be the case. 



It seems probable from the luxuriant growth obtained in 

 many of the uninoculated pots that the quantity of available 

 combined nitrogen present was large ; in some cases large 

 enough for the requirements of the plant, and so no beneficial 

 results could be expected from the inoculation. The produc- 

 tion of nodules also would have been retarded. 



The occasional injurious results produced by soaking the 

 seeds, reported in some cases, may have been responsible for 

 some of the instances in which a smaller yield was obtained 

 with the treated seed ; a point which could only be elucidated by 

 dressing the seed for the untreated pots with a similar solution, 

 but free from the organisms of the root nodules. It seems also 

 probable that in some cases Moore's cultures were dead, or in a 

 highly weakened condition. 



The experiments in which positive results were obtained show 

 that in many cases both Moore's and Hiltner's cultures were 

 alive, and capable of infecting the plants for which they were 

 designed and producing an increased yield. 



The results obtained in Section 2. — Pot cultures in various un- 

 sterilised soils should show in the case of sub-section (J?) (soils 

 from fertile fields) whether the preparations are capable of 

 increasing the production of nodules and giving a greater yield 

 in soils which already contain, or are supposed to contain, a 

 large number of nodule-forming organisms : the conditions 

 remaining the same as those in which the first scientific proof 

 of the preparations was made, and in which outside influences 

 were, as far as possible, eliminated. In sub-section (c) soils were 

 selected which were considered least likely to contain the re- 

 quired organism, and in which, consequently, the greatest effect 

 might be looked for as a result of the inoculation. In both cases 

 combined nitrogen was likely to be present in considerable 

 quantities. The age and previously proved inefficiency of some 



