Spirit materialisation. Illustration of a spirit materialising at a seance. The spirit was claimed to be formed of ectoplasm, a semi-luminous, thick vapour which oozed from the medium conducting the seance (at right). During this seance, the spirit has dipped its hands into softened paraffin wax to form a mould or wax glove. The small size of the mould's wrist opening and the position of the fingers was used as evidence that the glove could only have been formed by a hand that dematerialised afterwards. The men at centre are scientists from the Institut Metapsychique of Paris, France, who were observing the seance for signs of fraud. Illustration from the 1870s.