Daraming up - see water coverage 36, 60, 61, 130, 184, 190 



Dams, keeping in condition ISI 



Damselflies, dragonflies 33 



Danger point of acidity • 51 



Danger point of alkalinity 52 



Daphne 12, 13, 32 



Daphnide production 172 



Day-degrees 115 



Decalcification, biogenic 55 



Degeneration of the liver 198 



Degeneration phenomena in trout 106 



Denitrifying bacteria ^6 



Density of fish stock 39, UO, 128 



Depth of water 46 



Destructive activity of bacteria 45 



Detoxicated salt solutions 48, 162 



Detritus 11, 27, 172 



Detritus eaters 34 



Development duration of brook trout eggs 115 



Development time of carp eggs ••• 83 



Development time of trout eggs 115> 116* 



Development time of white-fish (marane) eggs 115 



Diaphanosoma 32 



Dlaptomus 32 



Dicalclum phosphate 168 



Digestibility of the nutrient substances 17, 23 



Digestible protein 18 



Digestion 15 



Digestion coefficient 17 



Digestion coefficient and temperature ••• •• 17 



Digestion of natural nutrition 16, 17 



Diptera 33> 36 



Disc cultivators • • 160 



Discovery factor 38 



Disease aggravation, cause of • 194 



l;lsease, gas bubble 198 



Disease, indications of 193 



Disease , nose • 197 



Disease origin •• 193 



Disease, pocks 199 



Disease, storage 203 



Disease, whirling 63, 95, 99, 102, 123, 124, 135, 206* 



Diseases, animal -parasitic 203 



Diseases, brood 84 



Diseases, crustacean-parasitic • 210 



Diseases, epidemic • 201 



Diseases, fission- fungus parasitic 201 



Diseases from infection 200 



Diseases , hyphomycete-parasitic 200 



Diseases, nodule 205 



Diseases, non-parasitic • 196 



Diseases, protozoan-parasitic 203 



Diseases, see fish diseases • 193 



Diseases, worm-parasitic 207 



Disinfection 163, 164 



Distributer of lime, see lime mill 166 



Ditch, moat 64 



Ditch scrapers 151 



Diver 192 



Diver, Black-necked 192 



Diver, dwarf 192 



Diver, North Sea 193 



236 



