(1850—1935) Famed French physiologist who won the Nobel Prize in 1913 for his work on understanding acute allergic reactions known as anaphylaxis. Richet also studied Spiritualism, investigated mediums, and became the president of the UK's famed Society for Psychical Research (in 1905). He believed that there was a physical explanation for mediumistic phenomena, rather than adhering to the idea that the phenomena were caused by spirits. He believed that some of the phenomena were caused by the medium's "sixth sense" (the ability to perceive non-physical "vibrations"), not spirits. Other phenomena, he believed, were caused by the medium projecting a material substance from their bodies. He called this substance "ectoplasm," a term that is still widely used.