Cyanamide, decomposition of, by fungi, 136. _Cyanophyceæ_, 103 (see also _Myxophyceæ_ and blue-green algæ). _Cylindrospermum_, 102. Cysts, 68, 73, 74. DENITRIFICATION, by bacteria, 37; by fungi, 136. Desiccation, resistance to, by algæ, 106. Dew, relation to algæ, 101, 113. Diatoms, 104 _sqq._ (see also _Bacillariaceæ_). Dicyanamide, decomposition of, by fungi, 136. Dipeptides, formation of, by algæ, 108. _Diplopoda_, 157. _Diptera_, 150, 154, 155, 159. Disaccharides and fungi, 134. EARTHWORMS, abundance of, in soil, 153; effect of, in soil, 13, 160, 175. Eel-worms, 149 (see also _Nematoda_). _Elaphomyces_, 132. _Enchytræidæ_, 149. Energy, laws of, 165; relationships of soils, 166; requirements of soil organisms, 15, 16. Energy supply, relation of bacterial activities to, 25 _sqq._, 40, 44; sources of, for soil bacteria, 26 _sqq._, 40, 43; supplies of, for soil organisms, 111, 164, 167, 168. Environmental conditions in soil, 16. Eremacausis, 2. Ericales, 132, 135. _Euglena_, 99. _Euglenaceæ_, 100. Experimental error, in bacterial counts, 54; in fungal counts, 124. FARMYARD manure, see Manure. Fats, used by fungi, 134. Fatty acids used by fungi, 134. Fertility of soil, views on, 2; effect of decomposition of plant residues on, 1, 165; effect of organisms on, 175. Filter paper, destruction of, by fungi, 133; destruction of, by _Spirochæta cytophaga_, 28. Fixation of nitrogen, discovery of, by Berthelot, 5; by bacteria, 40 _sqq._; by algæ, 110, 111; by mixtures of bacteria and algæ, 111; by fungi, 135 _sqq._ (see also Nitrogen Fixation). _Flagellatæ_, 100. Flax sickness and fungi, 122. Formaldehyde, as agent for destroying fungi, 141. Fungi, control of, in soil, 139 _sqq._; counting of, 122; distribution of, in soil, 119 _sqq._, 127; fertilisers, effect of, on numbers of in soil, 126; as facultative parasites, 131, 132; fruiting bodies of, 123; destruction of hemicelluloses by, 133; individual, 122, 123; action on monosaccharides of, 134; mineral relationships of, 139; mycorrhizal, 132, 135, 139, 140; heterocyclic nitrogen compounds and, 138; occurrence in soil, 118; qualitative study of, 118; selective feeding of, 140; specific determination of, 119. _Fungi imperfecti_, 119. _Fusaria_, 134. _Fusarium_, 119, 120, 122, 128, 133, 136. _Gamascidæ_, 156. Gases of swamp water (Paddy soils), 113. _Gastrodia_, 132. Gelatinous envelope of algæ, 109, 111. Geographical distribution of azotobacter, 41; of soil bacteria, 24; of protozoa, 75, 76; of soil fungi, 119, 125. Germination, of algal spores, 107. Glucose, use of, by algae, 108, 109, 111; use of, by moss protonema, 109. Glycocoll, formation of, by algæ, 108. _Granulobacter_, 42. Greenland, bacteria in soil from, 24. “Grunlandmoor,” fungi in, 126. _Hantzschia_, 105. _Hemiptera_, 154. _Heterokontæ_, 100.