Collection of a significant number of cases of self-induced photogenic epilepsy was stimulated by the interest and prolonged discussion which followed J. R. Davidson's contribution at the meeting of the Electroencephalograpy Society on Oct. 12, 1957, since published in full.1 A number of papers, each dealing with only a few cases, have appeared in the literature. From this it appears that a fair number of authors have encountered such cases, although there appear to be very few in any one paper. In confirmation of the rarity of these cases, Gastaut reports these figures from his own department at Marseille: "Out of the epileptics examined at Marseille 15% only produce spikes and waves during intermittent photic stimulation; only 3% display a clinical light sensitivity such as difficulty with sun or other strong light and the need to wear dark glasses. Four in 1,000 only have shown either grand mal or