INDEX OF SUBJECTS 



Trifolium, nodule bacteria of, 130, 



134, 135, 136 

 Trigonella, nodule bacteria of, 135, 136 

 Trilobus, 350 



Trimethylamine in soil, 479 

 Trinema, 332 

 Triphaena, 358 

 Tripyla, 348, 350, 358 

 Trochalworms in soil, 342 

 Trochelminthes in soil, 342 

 Trochilia, 335 

 Trochiscia, 224, 225, 228 

 Trombidiidae, 355 



Trophic protozoa in the soil, 47, 326 

 Tuber formation and plant evolution, 



273 

 Tuberculareaceae, 3, 257 

 Tumbler method, 687 

 Turbellaria in soil, 341, 345 

 Tylenchorhynchus, 348 

 Tylenchus, 348, 349, 350, 810, 818 

 Tylopharynx, 350 

 Tyroglyphidae, 355 

 Tyrosine, decomposition of, 484 



U 



Ulmic acid, 697 



Ulmin, 697 



Ulothrix, 225, 228 



Ultramicroscopic organisms in the 



soil, 5 

 Ur eolus, 334 



Urea as a source of nitrogen, 299 

 Urea bacteria, 27, 60, 151, 202-211 



anaerobic, 176, 210 



classification of, 208 



influence of oxygen tension on, 210 



isolation of, 207 



numbers of, in soil, 37, 38, 207 

 Urea, formation of, in the decomposi- 

 tion of proteins, 299 



formation of, in the decomposition 

 of uric acid, 212, 486 



decomposition of, 206, 486, 487 



nitrate agar, 16 

 Uredinales, 257 

 Uric acid, 206, 211, 486, 487 



bacteria, 60, 211 



Urine, bacteria in, 30 



Urobacillus, 208, 488 



Urobacterium, 209 



Urococcus, 208 



Urocystis, 811 



Uroleptus, 336 



Uronema, 335 



Urophlyctis alfalfae in soil, 808 



Urosarcina, 208 



Urostyla, 336 



Urolricha, 335 



Ustilaginales, 257 



Utilization quotient, 416 



Vacuum, use in the cultivation oi 



bacteria, 170 

 Vaginicola, 336 

 Vampyrella laterita, 331 

 Variability, of actinomyces, 304 



of bacteria in soil, 20 

 Vaucheria, 228 

 Vegetable organic matter, composition 



of, 427 

 Velvet bean, nodule bacteria of, 136 

 Vertebrates in soil, 31, 342, 362 

 Verticillium, 254, 258, 260, 265, 278, 812 

 Vibrio cholerae, 806 

 denitrificans, 187 

 thermo-desulfuricans, 189, 611 

 Vibrion septique, occurrence of. in 



soils, 173 

 Vicia, nodule bacteria of, 130, 134, 



135, 136 

 Vigna, nodule bacteria of, 135, 136 

 Vinca minor, mycorrhiza formation by, 



277 

 Virulence of nodule bacteria, 588 

 Volcanothrix silicophila, 647 

 Vorlicella, 336 



W 



Washed agar media, 70 



Water blanks for counting bacteria, 19 



Waxes, decomposition of, 463 



Waxes in soil, 463, 671 



Wheat nematode, 348 



Wheel animalcules in soil, 342 



