170mm x 244mm Collerton c10. tex V3-11/21/2014 5:28 P. M. Page 220 220 CH10 GEOMETRIC VISUAL HALLUCINATIONS Figure 10. 1 Heinrich Klüver. c. 1970. Source: Adapted from “Biographical Memoirs Volume 73,The National Academies Press,Washington DC 1998”. (a) (b) Figure 10. 2 (a) 'Phosphene' produced by deep binocular pressure on the eyeballs. Source: Redrawn from Tyler (1978). (b) Honeycomb hallucination generated by Marihuana. Source: Adapted from Clottes and Lewis-Williams (1998). Klüver was for many years a faculty member at the University of Chicago, retiring in 1963. But he remained active for several years, eventually developing a form of dementiaafewyearsbeforehisdeathin1979. Ibecamea Professoratthe University of Chicago in 1967, but only became interested in visual hallucinations in 1977. Unfortunately, by then it was no longer possible to discuss the topic with Klüver.