_Photinus_, 44, 51, 53, 56, 59, 64, 103, 125, 160 ff _Photoblepharon_, 18, 64, 69 Photochemical reactions, 67, 68, 138, 145 Photogen, 102 Photogenin, 105 Photoluminescence, 26, 67 Photophelein, 105, 106, 110 Photosynthesis by animal light, 18 _Photuris_, 44, 59, 103, 125, 160 ff Pierantoni, V., 13, 14, 74 Piezoluminescence, 32 ff Polarization, 45 Polimanti, O., 45 Pope, W. J., 32 _Porcellio_, 13 _Porichthys_, 70, 83 Preluciferine or proluciferine, 106 ff Prevost, B., 15 Priestly, 91 _Ptychodera_, 71, 103 Purkinje phenomenon, 40, 44, 157 Pyrogallol and luminescence, 37, 111, 148 ff Pyroluminescence, 24 Pyrophorine, 31, 109 _Pyrophorus_, 11, 43, 45, 49 ff, 64, 76, 101, 103, 114, 125 _Pyrosoma_, 10, 13, 45, 72, 101 Quatrefages, A. de., 73 Radiant energy, 20 ff Radioluminescence, 26 Radium rays or Becquerel rays, 21, 26, 30, 62 Radziszewski, B., 37, 39 Reaction velocity and luminescence, 145 ff Reductase, 130 ff Reeves, P., 65, 144 Respiration and luminescence, 91, 92, 99 _Rhizomorpha_, 2 Romberg's phosphorus, 32 Russel, E. J., 147 Russel, W. J., 62 _Sapphirina_, 14 _Sarcina_, 1 Scharff, E., 147 Scheele, 91 _Schistostega_, 15 Schizopod larvæ, 11 Schumann rays, 21 Schurig, W., 61 _Scolopendra_, 102 Sea, phosphorescence of, 2 _Sepietta_, 72 _Sergestes_, 72, 78 Singh and Maulik, 61 Solen, 116 Spallanzani, L., 85, 101 Spectrum of chemiluminescence, 39 Spectrum of luminous organisms, 42 ff Spectrum of phosphorescence, 28 Spectrum, range of, 21 ff Spinthariscope, 30 Steche, O., 65, 69 Stefan-Boltzmann Law, 22, 23 Stimulation and luminescence, 68 ff, 135 Stoke's Law, 28, 31 _Stylochiron_, 72 Suchsland, E., 61 Sulphides, phosphorescence of, 27 Sweat, luminous, 17 _Talitrus_, 13 Tarchanoff, J., 13 Temperature and luminescence, 145 ff, 156 ff Temperature radiation, 23 _Thaumatolampas_, 42 Thermoluminescence, 24 ff _Tomopterus_, 72 Transparency of chitin to infra-red, 52 Trautz, M., 32, 33, 37, 39, 145 Triboluminescence, 32 ff Trojan, E., 11, 78 Tschugaeff, L., 32 Ultra violet rays in animal light, 53 ff Urine, luminous, 18 Uses of luminous organs, 81 ff Vacuolides, 73 van Helmont, 91 van't Hoff, J. H., 147 _Vibrio_, 65 Ville and Derrien, 111 Visual sensibility, 54 ff Watanabe, H., 75 Watasenia, 104 Water and luminescence, 85, 101 Weiser, H. B., 33, 34, 39 Welker, W. H., 121 Wheeler and Williams, 77 Wiedemann, E., 23 Wiedemann and Schmidt, 25, 36 "Will-o'-the-wisp," 15 Wood, phosphorescent or shining, 1, 2, 85 Worms or annelids, 3, 72 X-rays or Röntgen rays, 21, 26, 30, 62 Yatsu, N., 75 Young, C. A., 43 Zacharias, O., 71 Zymogen granules, 73 * * * * * Transcriber's Notes