1. The term “dark” is very arbitrary. To some extent it is opposed to the term “induced” chemiluminescence. However, the term “very weak” chemiluminescence is no better. Moreover, we can hardly call this emission “spontaneous,” since it depends strongly on the external conditions (see Section 4.1).
2. A number of authors [Kaznacheev et al (1964); Kaznacheev (1965); Kaznacheev et al. (1965a-d)] also discovered visible emission in blood cells and some other objects, using the photoelectric method. However, the molecular mechanisms of this emission were not analyzed.
3. At present this term is often used to denote the chemiluminescence emission of biological objects in the UV, independently of the detector used.
4. The luciferin and luciferase of Cypridina are used as a convenient model for studying the action of irradiation and protective substances [Lohmann et al. (1963, 1964)). Moreover, it has been shown that luciferin exhibits anticarcinogenic activity [Shinazo (1964)].
5. This is not in accordance with earlier results [Gill (1963)], according to which the thermoluminescence peak of, e.g., tyrosine appears at 124°K, and the curves of phenylalanine have two peaks, at 113 and 155°K, which are due to the existence of two metastable levels (traps) of different energies. These discrepancies may be ascribed to different starting states of the materials used in the above studies and to the fact that different rates of heating may affect sharply the position of a given peak and its resolution on the corresponding curves [Lushchik (1955)].