The luminescence maximum represents the point at which luciferase is reversibly changed so as to be no longer active. If the temperature is again lowered the luciferase again becomes active and light reappears. Some degrees above this, and in all forms well below the boiling point, luciferase is coagulated and destroyed. As the coagulation point of proteins depends on many factors, such as time of heating, salt content, acidity, etc., so the luciferases of different animals coagulate at different temperatures depending on these conditions. Some of the more reliable observations on these critical temperatures are collected in Table 14. TABLE 14 _Temperature Limits of Luminescence for Luminous Organism_ -------------------------+---------------------+-------+-------+-------+ Organism | Author and date |Minimum|Optimum|Maximum| -------------------------+---------------------+-------+-------+-------+ Pseudomonas javanica | Eijkman, 1892 | -20° | 25-33°| 45° | | | | | | Bacterium phosphorescens | Lehmann, 1889 | -12° | ... | 39.5° | | | | | | Bacterium phosphoreum | Molish, 1904, book | -5° | 16-18°| 28° | | | | | | Light bacteria | Tarchanoff, 1902 | -7° | 15-25°| 37° | | | | | | Light bacteria | Harvey, E. N., 1913 | -11.5 | 15-20°| 38° | | | | | | Mycelium X | Molish, 1904 | ... | 15-25°| 36° | | | | | | Lampyrids | Macaire, 1821 | -10 | 33° | 46-50°| | | | | | Pyrophorus noctilucus | Dubois, 1886 | ... | 20-25°| 47° | | | | | | Photuris pennsylvanica | Lund, 1911 | ... | ... | 50° | | | | | | Luciola viticollis | Harvey, E. B., 1915 | <0° | ... | 42° | | | | | | Cypridina hilgendorfii | Harvey, E. N., 1915 | <0° | ... | 52-54°| | | | | | Cyclopina gracilis | Lund, 1911 | ... | ... | 50° | | | | | | Phylirrhoë bucephalum | Panceri, 1872 | 44° | ... | 61° | | | | | | Pyrosoma | Panceri, 1872 | <0° | ... | 60° |