Among the lizards, a gecko has been mentioned as a light-giver, as if these curious creatures were not remarkable enough in themselves without this attendant phenomenon. According to Dr. Carpenter, the eggs of the gray lizard have been seen to emit light; and in Surinam he states that a frog or toad is luminous, especially in the interior of its mouth. Thus we see that this strange light is found in some form from the lowest to the highest animals,--one of the commonest of phenomena, yet presenting a problem defying solution. CHAPTER XV. MAN’S RELATIONS TO THE PHENOMENON OF PHOSPHORESCENCE. Dr. Phipson, the eminent scientist, states that he once observed certain phenomena in man, the light being a brilliant scintillation of a metallic pink color. It is well known that human beings under certain physical conditions become luminous. In some cases among the ignorant great excitement has been occasioned, and the victim avoided as a pest, or something capable of dire disaster to the entire community. In a small German village, an English physician discovered a man who was luminous at night, and who had caused much alarm among the superstitious. Bartholin records an instance of an Italian lady whom he calls _Mulier splendens_, who suddenly found that, when rubbed with a linen cloth in the dark, her body gave out a brilliant phosphorescent light; so that she appeared in a darkened room like a veritable fire-body, an awe-striking object to her superstitious servant, who fled from her speechless with fear and amazement, thinking that her mistress was being consumed.