284 FORMATION OF SLIME OR GUM BY RHIZOB1UM LEGUMINOSARUM, 



An incubation temperature of 22° was used in these 

 experiments, chiefly for the sake of convenience. This might, 

 however, not be the optimum. Experiments were tried with 

 several races with the following results : — 



The Influence of Temperature. 





Experiment I 



Experiment 2 



Experiment 3 





(saccharose 



(saccharose and 



(dextrose and 





and citrate). 



phosphate). 



phosphate). 





22° 

 13 



28° 

 21 



37° 

 



16° | 22° 



26° 

 17 



30° 

 15 



16° 22° 



26° 



30° 



Robinia 



8 



16 



French Bean 



6 



1 



1 



5 



4 



3 







3 4 



2 







Black Tare 



2 



2 







1 



3 



1 







— — 



— 







Pea (Oct.) 



4 



2 





















Pea (March) 



3 



2 



1 



3 



12 



5 



1 



2 5 



1 



1 



Lupin (K) ... 



— 



— 



— 



5 



3 



1 







2 5 



2 







Pea (K) 



— 



— 



— 



2 



2 



2 







2 3 



2 



1 



Macrozamia 







~ 



6 



10 



8 







— — 



— 



— 



The optimum temperature for the majority of the races lies 

 about 22° while the Robinia race grows best at about 26°C. 



The slimes were generally alkaline in the presence of citrate 

 and acid when phosphate had been used in the medium. The 

 influence of the reaction of the medium was tested upon two 

 occasions. On the first of these, two Krai races were grown 

 upon media containing saccharose, asparagin and tartrate, to 

 which varying quantities of normal sulphuric acid and sodium 

 carbonate had been added. On the second occasion, four New 

 South Wales races were grown upon media containing dextrose 

 and phosphate, to which different amounts of normal phosphoric 

 acid and sodium carbonate were added before pouring the plates. 



