183 



Nitrogen sources 



Nitrification : nitritation, influence of or- 

 ganic substances, III. 113, 238; IV. 

 261; V. 181; VI. 71. 



— W i n o g r a d s k y's theory of chemo- 

 synthetic carbon dioxide assimilation, 

 III. 238; IV. 180. 205, 206, 379; V. 191. 



uitrite: assimilation by microorganisms, 



111. 7, 8. 11, 22, 31, 183; IV. 339; 



V. 16, 273; VI. 61. 



— formation, demonstration, III. 18, 19, 

 20, 117, 190; IV. 195; V. 184, 185. 



— oxidation as an energy source in che- 

 mosynthesis, IV. 379; V. 191. 



Nitrite bacteria (nitrous bacteria) : III. 

 113, 189; IV. 240; V. 181-184; VI. 71. 



— cultivation, III. 190; VI. 71. 



— description, IV. 261, 265*; VI. 71. 

 Nitrogen compounds: influence on Azo- 



tobacter enrichment cultures, IV. 110- 



112. 149. 377. 383; V. 122; VI. 4. 7. 21. 



— influence on Azotobacter pure cultures. 

 IV. 117. 119, 122, 139, 140. 



— influence on Bacillus radicicola, II. 

 164, 183, 184, 323, 324; III. 50; IV. 

 115, 119; V. 269; VI. 61. 



— influence on Cyanophyceae, IV. 106, 

 107, 126, 127, 239; V. 135. 



— influence on root nodules. II. 323. 



— influence on Spirillum lipoferum, VI. 

 6, 21.24. 



— microbiocheinical quantitative de- 

 termination, III. 7-10. 



— nutrition of unicellular green Algae, 

 II. 296, 297, 300, 308, 313. 316; III. 

 22, 24; IV. 106-108, 126, 239; V. 134. 

 135. 



— present in air, VI. 61. 69. 70. 



— quantity present in tapwater and soil, 

 IV. 106, 125,256. 



Nitrogen cycle in the soil and in the sea, 

 IV. 174, 178, 258. 260, 262; V. 232. 



Nitrogen fixation: by Aerobacter in 

 symbiosis with Azotobacter, IV. 139, 

 140. 146. 



— hy Azotobacter, f irst discovery. IV. 175. 



— by Azotobacter, experiments with pure 

 cultures, IV. 166-168. 298-301. 304; 



VI. 4. 



— by Azotobacter in combination with 

 other bacteria, IV. UI, 118, 139-145. 

 149. 150, 159. 164. 165-170. 175, 176. 

 256*. 257. 258. 262. 300-302, 377; V. 

 232; VI. 3. 



— by Azotobacter, influence of acidity, 

 IV. 143. 257. 



Nitrogen fixation: hy Azotobacter, influ- 

 ence of calcium. IV. 111. 122. 143, 

 298-300, 302; VI. 3. 



— by Azotobacter, influence of oxygen. 



IV. 302. 



— by Azotobacter, influence of the salts of 

 organic acids. IV. 110. 112. 113. 143. 

 1 6 1 , 1 65, 1 75, 298-300. 302 ; V. 23 1 ; VI. 

 4. 21-23. 



— by Azotobacter, quantity, IV. 154- 

 159, 164. 300-303. VI. 3, 4, 26. 



— hy Bacillus mesentericus, IV. 167. 169, 

 178. 



— by Bacillus radicicola, experiments. 

 II. 183-185. 323. 324; IV. 259; V. 

 264-271; VI. 61-70. 



— by Bacillus radicicola in symbiosis 

 with Papilionaceae, IV. 256, 258, 259; 



V. 267, 268. 



— by Bacillus radiobacter, IV. 144, 163, 

 170. 179.257. 



— by bacteria, IV. 105-127, 139. 179. 

 180, 205, 256*, 257, 262, 298-304; 379; 

 V. 135. 229, 231, 232, 264-271 ; VI. 3-8. 

 21-27. 



— by bacteria. annual quantity in the 

 soil. V. 232; VI. 26. 



— by Cyanophyceae, IV. 108. 127. 183, 

 239; V. 135. 229. 



— by Cyanophyceae, annual quantity in 

 the soil. V. 229. 



— by Granulobacter in symbiosis with 

 other bacteria. IV. 152. 153, 161. 175. 

 178. 179; V. 231. 232; VI. 3. 



— by Granulobacter in pure culture, IV. 

 UI. 139, 149-153. 161. 164. 167, 173, 

 178, 179; V. 267. 



— by Helobacter, V. 267. 



— by mixtures of pure cultures, IV. 145, 

 167-170-175. 



— by Spirillum lipoferum, VI. 21-24-27. 



— determination of the quantity, IV. 

 154, 155. VI. 66-68. 



— first assimilation product, IV. 140, 

 178, 260; V. 232. 



— with cellulose as a carbon source. IV. 

 256*. 257, 262; V. 232. 



Nitrogen f ixing power of the soil. VI . 25, 26. 

 Nitrogen loss of the soil, IV. 18. 

 Nitrogen sources for microorganisms, 



II. 201, 256. 296-298, 316, 337, 338; 



III. 7-11. 18-22. 30-32. 61, 133, 183. 

 184, 276, 277; IV. 28, 73, 81. 91, 118. 

 200, 226, 279, 297, 353-355; V. 5. 8. 9. 

 16-18. 202, 273. 



