Note 518 — Chapter XXVII
Reading edition
The suggested hallucination may be followed by a negative after-image, just as if it were a real object. This can be very easily verified with the suggested hallucination of a colored cross on a sheet of white paper. The subject, on turning to another sheet of paper, will see a cross of the complementary color. Hallucinations have been shown by MM. Binet and Féré to be doubled by a prism or mirror, magnified by a lens, and in many other ways to behave optically like real objects. These points have been discussed already on p. 138 ff.