"280 FORMATION OF SLIME OR GUM BY REIZOBIUM LEGUMINOSARVM, 

 The Influence of Vabiods Forms of Nitrogen. 





Q Ex P> L Expt. 2. 

 Saccharose , j u u a 



, ., , 1 Saccharose and phosphate, 

 and citrate. r r 



Expt. 3. 



Dextrose and 



phosphate. 



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CD 



CD 



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pq 



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pq 



Pu 



£ 



§ 



PS 



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pq 



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fe 



« 



A spar agin 



10 



10 



10 



10 



10 



10 



10 



10 



10 



10 



10 



10 



10 



10 



10 



10 



Urea 



9 



8 



9 



9 



4 



10 



8 



6 



9 



10 



4 



4 



11 



8 



3 



8 



Peptone ... 



3 



5 



3 



9 



6 



8 



11 



10 



4 



11 



5 



5 



11 



8 



4 



4 



Potassium 



































nitrate ... 



11 



10 



11 



12 



5 



17 



11 



6 



16 



15 



6 



6 



13 



10 



3 



9 



Ammonium 



































sulphate.. 



9 



7 



8 



8 



1 



— 



5 



3 



4 



2 



3 



4 



3 



3 



6 



— 



Ammonium 



































phosphate 



— 



— 



— 



4 



3 



7 



6 



6 



6 



— 



3 



4 



— 



— 



7 



5 



Asparagin 



































actual % 



17 



17 



17 



3 



4 



7 



8 



4 



10 



17 



3 



3 



10 



13 



11 



20 



The experiments show that either asparagin or potassium 

 nitrate can be accepted as being the most suitable nutrient for 

 feeding the micro-organism in order to obtain a maximum of 

 slime. After these come peptone, then urea, and finally ammonia. 

 It must be remembered that equivalent quantities of these were 

 present; while the asparagin tests contained - 06 %. the urea 

 media contained 0-024 %. It will be noted that in some cases 

 ammonium phosphate was used, and the yields show that the low 

 results with ammonium sulphate were chiefly due to the ammo- 

 nium and not to the presence of free sulphuric acid in the media 

 as growth proceeded. The plates with the ammonium salt were 

 always more acid than the others at the end of the experiment, 

 but this is only what may be expected in the case of a salt, the 

 base of which is utilised by the micro-organism. The addition 

 of small quantities of alkali as suggested by the " influence of 

 reaction " experiment which follows later had but little effect in 



