INDEX OF SUBJECTS 



869 



Ammonia formation, rate of, 375, 495, 



688 



factors influencing, 688-689 



methods of determination, 497 

 Ammonia oxidation, by chemical agen- 

 cies, 524 



mechanism of, 525 

 Ammonification studies, 687 (see also 



Ammonia-formation) 

 Ammonium salts, nitrification of, 715 

 Amoeba, 331, 332, 337 

 Amoebae, in soil, 2, 47, 315, 326, 328 



cultivation of, 319 

 Amoebida, 331 



Amorpha, nodule formation by, 137 

 A?nphicarpa, nodule formation by, 137 

 Amphileptus, 335 

 Amylobacter group of bacteria, 106 



(see Bac. amylobacter) 

 Amylomyces boidin, 462 

 Amystidae, 355 

 Anabaena, in soil, 217, 224, 227 



in the roots of cycads, 138, 302 

 Anachaeta, 354 

 Anacystis, 226 

 Anaerobic bacteria, 4, 141, 160-179 



classification of, 172 



cultivation of, 169 



decomposing celluloses, 166, 437 



decomposing pectins, 203 



facultative, 160 



isolation of, 164 



nitrogen-fixing, 107 



numbers of, in soil, 38, 175 



obligate, 163 



physiology of, 176 

 Anaerobic conditions in soil, 164 



utilization of energy, 412 

 Aniline dyes, use of, in the separation of 



soil bacteria, 166 

 Anguillula, 350 



Animal diseases caused by, actinomyces 

 in soil, 809 



bacteria found in the soil, 805 

 Animal ecology, 341 

 Anisonema, 334 

 Ankistrodesmus, 228 

 Annelida in soil, 341, 351, 354, 359 



Anorgoxydants, 61 

 Anthracnose of beans in soil, 815 

 Anthracriny, 694 



Antiseptics, volatile, influence of, on 

 bacterial activities, 744-745 749- 

 759 

 Aphanethece, 226 

 Aphanocapsa, 226 

 Aplianomyces, 247, 808, 813 

 Aphelenckus, 348, 349, 810 

 Apocrenic acid, 697, 698 

 Arachnida, 354, 355, 357, 359 

 Arachnis, nodule formation by, 136 

 Arbutus unedo, mycorrhiza formation 



by, 274, 804 

 Arcella, 332 

 Arcellidae, 332 

 Archiboreoiidus, 355 

 Archionchus, 350 

 Archivortex, 345 

 Ardisia, bacteria in, 105, 139 

 Areinida, 355, 357 

 Arid soils, distribution of bacteria in, 



36 

 Arginine in soil, 479, 671 

 Armillaria, 276, 284 

 Arsenic compounds, oxidation of, 540 



reduction of, 303, 540, 556 



influence of, on bacterial activities, 

 534, 668 

 Arthobotrys, 255 

 Arthropodainsoil, 341, 354, 359 

 Ascomycetes, 3, 249, 250, 259, 277 

 Asparaginate agar, 16 

 Aspergillaceae, 242, 267 

 Aspergillus, in soil, 3, 238, 245, 251, 253, 

 258, 259, 260, 265, 443, 459 



flavus, 454, 465 



fumigatus, 444, 454, 495, 817 



fuscus, 444 



glaucus, 444 



niger, 243, 244, 380, 382, 411, 415, 

 416, 417, 454, 462, 464, 467, 494, 

 503, 511, 514, 637, 650, 652 



oryzae, 261, 454, 462 



repens, 454 



terricola, 261, 490, 637 



wentii, 444 



