BY E. GREIG-SMITH. 



281 



reducing the final acidity or in increasing the yield in the 

 ammonium salt tests. 



The results indicate that the Krai races of the Lupin and the 

 Bean are the same, and that all the other races differ one from 

 the other. Dextrose shows a difference even between the March 

 and October races of the Pea. 



The Optimum Percentage of Nitrogenous Nutrient. 



Percentage 



of nutrient 



added. 



Expt. 1. 



Macroz unia 



with citrate 



and 



asparagin 



Expt. 2. 

 Macrozamia 

 with phos- 

 phate and 

 asparagin 



Expt. 3. 

 Macrozamia 

 with citrate 



and 

 ammonium 

 sulphate 

 (14 days). 



Expt. 4. 



Dextrose, phosphate and asparagin. 



(7 days). 



Robinia 



Pea 



French 





(9 days;. 



(14 days). 



at 26°. 



(March). 



Bean. 



None 



1 



1 





5 



2 



1 



0-01 



3 



4 



— 



9 



6 



3 



0-02 



— 



6 



— 



12 



9 



5 



025 



11 



— 



18 



— 



-- 



— 



0-03 



— 



7 



— 



14 



13 



6 



04 



— 



8 



— 



16 



16 



8 



0-05 



15 



10 



25 



18 



— 



10 



0-06 



— 



11 



— 



21 



19 



11 



0-075 



17 



— 



— 



— 



— 



— 



0-08 



— 



12 



— 



23 



17 



13 



010 



15 



11 



24 



27 



17 



6 



0-12 



— 



11 



— 



28 



15 



8 



0-15 



14 



— 



19 



— 



— 



— 



0-20 



— 



— 



15 



— 



— 



— 



0-25 



14 





15 



" 



" 



" 



The races differ with regard to the influence of increasing 

 quantities of nutrient in the medium. The Robinia race responds 

 steadily to the gradual addition of asparagin, while the other 

 races show an optimum between 0*04 and 008 %. Thus the 

 Robinia race shows a marked difference from the other races. 



The steady rise of slime with increasing quantities of nitro- 

 genous nutrient points to there being no gain or fixation of 

 nitrogen from the atmosphere. The Robinia race is a good slime- 

 former, and this fact may account for the comparatively high 

 yield in the test in which no nitrogen was added. There is, how- 

 ever, the possibility that there might have been a slight gain of 



