i66 



INDEX 



Bacteria, counting, 16-20 

 effect of cultivation on number of, 



31 

 of depth on number of, 22, 23 



of limestone on number of , 27, 28 

 of manures on number of, 25, 26 

 of moisture on number of, 24, 25 

 of partial sterilization on number 



of, 28, 29 

 of plant roots on number of, 29 

 of season on number of, 30 

 iron precipitating, 84 

 nitrogen content of, 74 

 number, according to dilution 

 method, 16 

 to plate method, 18 

 in artificial cultures for inoculat- 

 ing legumes, 73 

 Bean extract, 11 1 

 Berkefeld filter, 37 

 Biuret reaction, 140 

 Blank, 25 



Blood-meal, ammonification, 39 

 Bouillon, 89, 90 



nitrate, 106 

 Brucin reagent, 137 



Caffein agar, no 



effect on nodules, 72 

 Calcium carbonate for soil acidity, 27 

 Capsule stain, 130 

 Carbol-fuchsin, 127 

 Carbon bisulphid, effect of, on num- 

 ber of bacteria, 28 



cycle, 75-80 



dioxid, determination of, 149--151 

 formation of, from organic sub- 

 stances, 78 

 Casein, agar, 94 



ammonification of, 39 



nitrification of, 51 



solution, 98 

 Catalase, 32-34 



Catalytic power of soils, 32-34 

 Cellulose, agar, 113 



bacteria, isolation of, 77 



fermentation by denitrifying bac- 

 teria, 77 

 in impure cultures, 75 

 in soil, 76 

 solution for, 112 



fermenting molds, solution for, 113 



hydrated, 113 

 Centigrade scale, 162 

 Chlamydothrix, solution for isolat- 

 ing, 118 



threads, 85 

 Ciliates, growth, 18 

 Citric acid reagent, 138 

 Cleaning glassware, 88 

 Clostridium pasteurianum, 66 

 Clover, agar, 122 



bacteria, 67 



hay, ammonification of, 39 

 Cochineal 134 

 Collodion sacs, 104 

 Colonies, spreading, 20 

 Control, 25 



Counting bacteria, 16-20 

 Crenothrix, method for growing, 84 



threads, S5 

 Crone's solution, 125 

 Cultivation, effect of, on number of 



bacteria, 31 

 Culture-media, comparison of num- 

 ber of bacteria on different, 21 



filtration of, 92 



neutralization of, 90, 91 



preparation of, 89-126 



reaction of, 90, 91 



titration of, 90, 91 



Denitrification by pure cultures, 

 57, SS 

 in inorganic solutions, 60 

 in soil, 59 



