Subliminal therapy has been used for many decades, dating back as far as the early 1900's. The first recorded use of subliminal messages was seen in the form of whisper therapy, in which a therapist whispers suggestions to the patient in hopes of subconsciously persuading the patient to improve his/her behavior. In the whisper therapy example, the therapist whispers the suggestion to the patient at a level inaudible to the conscious mind, or at a time when the patient is not expecting it. If the patient is unaware of the suggestion because it is below his/her level of awareness, the suggestion will be entered into the subconscious mind. Though use of subliminal messages was not recorded until the twentieth century, research began much earlier. The research of Suslowa in 1863 demonstrated that there is a threshold between conscious and subliminal that was seen through the use of "subliminal electrical stimulation." The patient was administered electrical impulses at different levels of intensity, and brain activity was observed to change at the specific threshold point. This border between the conscious and subconscious varies slightly from person to person. In his 1894 work The Science of Vital Force, W. R. Dunham, M.D., wrote of many concept that today are generally accepted by the public as science fiction or fantasy. This writing discussed the concepts of subliminal and supraliminal consciousness (supraliminal means "consciously unnoticed"; subliminal means "consciously not perceivable") as well as the concepts of telepathy and clairvoyance. Telepathy, according to Dunham, is silent communication on the level of subliminal consciousness in which the subliminal consciousness of one individual may learn what is in the subliminal or supraliminal consciousness of the other. (Taylor 1) The telepathic transfer of information is the topic of yet another research project. Messages are transferred mechanically through the bioplasma (also known as corona discharge or aura). The aura, as it is most commonly called, is an electromagnetic field that can be seen by electrophotography (also called Kirlian photography). Soviet medical doctors have used electrophotography to diagnose physical and mental disorders that can be seen in the bioplasma. Hidden Persuaders by Vance Packard could be found on the reading lists of many high schools in the late 1960's. This book was highly discredited by its opposition when it was published in 1957. This book published numerous case studies of subliminal messages that had obvious observable results. Packard quoted a London Sunday Times issue in which a New Jersey theater claimed that ice cream sales soared due to the flashing of ice cream ads on the movie screen in what was called a "subthreshold effect." Packard also asserted that the words blood, knife, and murder were used subliminally in Alfred Hitchcock's famous movie Psycho to heighten fear in his audience.