Ectoplasm (from the Greek ektos, meaning 'outside', and plasma, meaning 'something formed or molded') is a term used in spiritualism to denote a substance or spiritual energy 'exteriorized' by physical mediums. It was coined in 1894 by psychical researcher Charles Richet. Although the term is widespread in popular culture, the physical existence of ectoplasm is not accepted by science and many purported examples were exposed as hoaxes fashioned from cheesecloth, gauze or other natural substances.Because ectoplasm was believed susceptible to destruction by light, the possibility that ectoplasm might appear became a reason for making sure that Victorian séances took place in near darkness. Poor lighting conditions also became an opportunity for fraud, particularly as faux ectoplasm was easy to make with a mixture of soap, gelatin and egg white, or perhaps merely well-placed muslin. Ectoplasm (from the Greek ektos, meaning 'outside', and plasma, meaning 'something formed or molded') is a term used in spiritualism to denote a substance or spiritual energy 'exteriorized' by physical mediums. It was coined in 1894 by psychical researcher Charles Richet. Although the term is widespread in popular culture, the physical existence of ectoplasm is not accepted by science and many purported examples were exposed as hoaxes fashioned from cheesecloth, gauze or other natural substances. In spiritualism, ectoplasm is said to be formed by physical mediums when in a trance state. This material is excreted as a gauze-like substance from orifices on the medium's body and spiritual entities are said to drape this substance over their nonphysical body, enabling them to interact in the physical and real universe. Some accounts claim that ectoplasm begins clear and almost invisible, but darkens and becomes visible, as the psychic energy becomes stronger. Still other accounts state that in extreme cases ectoplasm will develop a strong odor. According to some mediums, the ectoplasm cannot occur in light conditions as the ectoplasmic substance would disintegrate. The psychical researcher Gustav Geley defined ectoplasm as being 'very variable in appearance, being sometimes vaporous, sometimes a plastic paste, sometimes a bundle of fine threads, or a membrane with swellings or fringes, or a fine fabric-like tissue'. Arthur Conan Doyle described ectoplasm as 'a viscous, gelatinous substance which appeared to differ from every known form of matter in that it could solidify and be used for material purposes'. The physical existence of ectoplasm has not been scientifically demonstrated, and tested samples purported to be ectoplasm have been found to be various non-paranormal substances. Other researchers have duplicated, with non-supernatural materials, the photographic effects sometimes said to prove the existence of ectoplasm. The idea of ectoplasm was merged into the notion of an 'ectenic force' by some early psychical researchers who were seeking a physical explanation for reports of psychokinesis in séances. Its existence was initially hypothesized by Count Agenor de Gasparin, to explain the phenomena of table turning and tapping during séances. Ectenic force was named by de Gasparin's colleague M. Thury, a professor of natural history at the Academy of Geneva. Between them, de Gasparin and Thury conducted a number of experiments in ectenic force, and claimed some success. Their work was not independently verified. Other psychical researchers who studied mediumship speculated that within the human body an unidentified fluid termed the 'psychode', 'psychic force' or 'ecteneic force' existed and was capable of being released to influence matter. This view was held by Camille Flammarion and William Crookes, however a later psychical researcher Hereward Carrington pointed out that the fluid was hypothetical and has never been discovered. The psychical investigator W. J. Crawford (1881–1920) had claimed that a fluid substance was responsible for levitation of objects after witnessing the medium Kathleen Goligher. Crawford, after witnessing a number of her séances, claimed to have obtained flashlight photographs of the substance; he later described the substance as 'plasma'. He claimed the substance is not visible to the naked eye but can be felt by the body. The physicist and psychical researcher Edmund Edward Fournier d'Albe later investigated the medium Kathleen Goligher at many sittings and arrived at the opposite conclusions to Crawford; according to D'Albe, no paranormal phenomena such as levitation had occurred with Goligher and stated he had found evidence of fraud. D'Albe claimed the substance in the photographs of Crawford was ordinary muslin. During a séance D'Albe had observed white muslin between Goligher's feet. Ectoplasm on many occasions has been proven to be fraudulent. Many mediums had used methods of swallowing and regurgitating cheesecloth, textile products smoothed with potato starch and in other cases the ectoplasm was made from paper, cloth and egg white or butter muslin.