Wheat Cu, 16, 17, 23; Zn, 37, 44, 46; As, 52, 60; B, 66, 70, 72, 73; Mn, 79, 81, 83, 84, 85, 86, 87 Willow Zn, 39, 40 Yeast Zn, 50; B, 76 Zea japonica Cu, 17, 18 Mays (_see_ Maize) GENERAL INDEX Absorption capacity of soils for zinc, 41 of poisons by plants, 25 Accelerators, 45 Action of heavy metals in mixed solutions, 20 Adsorption, 8, 23 Aeration in water cultures, 8 Algae, assimilation of arsenic by, 62 clearing ponds of, 35 effect of arsenic on, 62 effect of boron on, 76 effect of copper on, 35 Aluminium, 45, 78 Arbutin, 4 Arsenate, potassium, 53, 62, 63 sodium, 55, 57, 61 Arsenates, 53, 57 Arsenic acid, 53, 54, 60, 61, 62, 64 acid v. arsenious acid, 53 acid v. phosphoric acid, 53, 62 elimination of, 59 gas liberated by moulds, 63 in soil, effect of, 58 in superphosphate, 58 Arsenious acid, 53, 54, 57–61, 64 immunity of plants to, 58 Arsenite, sodium, 55, 56, 61 Arsenites, 53, 57 v. arsenates, 57 Artificial oxydases, 84 soil, 24, 46 Assimilation, reduction in water plants, 48 Barium, 44 Borate, calcium, 71 potassium, 71 Borates, 72 Borax, 71, 73 Bordeaux mixture, 30 blocking of stomata by, 33 on assimilation, effect of, 33 Boric acid, 1, 65–76, 93 Boromannitic acid, 68 Boron, antiseptic action of, 70 colour due to, 75 distribution in plants, 66 poisoning, indication of, 68, 69 rôle in plant economy, 74 Cadmium, 31 Calamine, 37 plants, 38 soils, flora of, 37 Calcium carbonate, 4, 23, 25 chloride, 20, 59 sulphate, 20, 44, 45 Carbon black, 23 dust, 10 Catalytic elements, 49, 91 Chlorophyll, 44, 60 Complementary manures, 47, 91 Conditions of plant life, 7 Copper, acetate, 19 action on plant organs, 30 bicarbonate, 26 bromide, 19 chloride, 19, 20 compounds, corrosive action on plant roots, 5, 27 distribution in tissues, 16 mode of action on plants, 25 nitrate, 19, 25 oxide, 15, 25 quantity in certain plants, 17 salts, injection into plant tissue, 31 sprays, effect on leaves, 30, 32 sulphate, 5, 19, 20, 22–27, 29–35, 41 Cumarin, 4 Distilled water, preparation of, 10 Double decomposition in soil, 25 Duration of experiments, 13 Experimental methods, comparison of, 14 Ferric chloride, sublimed, 86 hydrate, 23 Fungi, effect of arsenic on, 63 effect of boron on, 76 effect of copper on, 33, 34 effect of manganese on, 90 effect of zinc on, 48 Galactose, 76 Glucose, 76