INDEX 



167 



Denitrification with formation of 



nitrous oxid, 58 

 Denitrifying bacteria, fermentation 

 of cellulose, 77 

 isolation of, 55 

 organisms, reduction of stains by, 



solution, 106 

 inorganic, loS 

 Depth, effect of, on number of bac- 

 teria, 22, 23 

 Dextrose and nitrate reduction, 59 



solution, 109 

 Dilution method of counting bac- 

 teria, 16 

 protozoa, 17 

 Diphenylamin reagent, 137 



Egg-albumen, 93 

 English units, 162, 163 

 Enrichment cultures, Azotobacter, 61 



cellulose, 77 



denitrifying, 55 



nitrifying, 50 



Fahrenheit scale, 162 

 Fehling's reagents, 138 

 Fermentation of cellulose by denit- 

 rifying bacteria, 77 

 in impure cultures, 75 

 in soil, 76 

 Filter, Berkefeld, 37 

 for culture-media, 92 

 paper for denitrifying solution, 107 

 in fermentation of cellulose, 75 

 Fixation of nitrogen in soil, 6 a 



in solution, 61 

 Flagella stain, Loflaer's, 130, 131 



Zettnow^s, 131, 132 

 Formulae, 88-126 

 Fuller's scale, 90 

 Fungi, agar, 121 

 solution for, 120, 121 



Gallionell\, S5 

 Gelatin, gt 



ammoniOcation of, 38 



for sulphate 1 eduction, 116 



soil extract, 95 



solution, 98 

 Gentian-\ iolet, 127 

 Giltay's solution, 106 

 Glassware, cleaning, 88 

 Gram's iodin solution, 127 



stain, 129 

 G3T)sum blocks, 105 



Hanging-drop, 61 

 Hay egg-albumen, 97 



infusion, 97 

 Hay-soil extract, 97 

 Heyden-Nahrstoff agar, 93 

 Higher plants, solution for, 1 24 

 Hippuric acid, 100 

 Hopkins and Pettit solution, 124, 125 

 Humus, determination of, 148 



formation of, 79 

 Hydrogen peroxid, 34 

 sulphid, determination of, 154 

 organisms, isolation of, 82 

 solution for its formation from 

 protein and sulphur, 117 



Incubation of plates, 20 

 Indol and skatol, 139 

 Iron cycle, 84-86 

 Iron-precipitating bacteria, 84 

 agar for isolation of, 119 

 Isolation of ammonifiers, 39 



of Azotobacter, 61 



of Bacillus radicicola from different 

 legumes, 67 



of cellulose fermenting bacteria, 77 



of chlamydothrix, 118 



of clostridiai, 6(> 



of denitrifying bacteria, 55 



of hydrogen sulphid organisms, 82 



