INDEX 



145 



Spirochaeta cytophaga, 134 

 Spore-forming bacteria, determina- 

 tion of, 101 



stain, 50 



yeast medium, 18 

 Staining of bacteria, 47 

 Starches, 71 

 Sterilization of media, 6 



of soil, 7 

 Straw, effect of on numbers of 



microorganisms, 103 

 Structure of the root nodule, 111 

 Suction filter, 4 

 Sulphates, reduction of, 128 

 Sulphur bacteria, 130 

 high forms, 130 



oxidizing bacteria, media for, 28 

 Sulphuric acid, normal solution, 54 



Transferring cultures, 90 

 Trommsdorf reagent, 57 

 Tubeuf's medium, 15 

 Truffaut and Bezssonoff medium, 12 



U 



Urea bacteria, isolation of, 127 

 media for, 21 

 citrate solution, 21 

 decomposition, 136 

 soil extract solution, 22 



Vegetable tissue for absorbing oxy 

 gen, 46 



W 



Tap-water gelatin, 11 

 Temperature and pressure, 7 

 Test for ammonia, 56 



for ferric iron, 133 



for hydroxylamine, 58 



for indol, 61 



for nitrates, 58 



for nitrites, 57 

 ThermophiUc bacteria, 38, 101, 134 

 Thiohacillus thioparus, 131 



thiooxidans, 132 

 Thionin, 48 



Thiosulphate solution, 28 

 Thomas' test reagents, 57 

 Thornton's medium, 11 

 Total carbon, determination of, 80 



nitrogen (Davisson-Parsons), 68 

 (Kjeldahl), 65 

 to include nitrates, 67 



Worms, number in soil, 105 

 Washed agar for nitrifying bacteria, 



23 

 Water-holding capacity of soil, 61 

 Winogradsky's direct count, 105 



glucose-peptone agar, 12 



medium, 11 



solution for Nitrosomonas, 22 



Yeasts and yeast spores, 96 

 infusion (dried), 17 

 infusion (fresh), 16 

 media for, 16 

 water sulphite agar, 27 



Ziehl's carbol fuchsin, 47 



