Intoxication with either produces general increase in brightness and size of corona. Hypnosis showed a similar pattern as above, though results are inconsistent. If a person trained in biofeedback or autosuggestion suggests to himself that his hand is getting warmer, there are specific structural changes in the luminescence observed only during the autosuggestion of warmth. If the trained person touches another person not trained in autosuggestion and the untrained person is photographed, he too shows the same structure of luminescence as the trained person. Some people are able to withhold their corona at will by tensing the muscles of their body.
Some people are able to consciously affect even the shape of their corona.
Below are pictures of Uri Geller's finger pads. The experimenter guided the subject's right forefinger tip to the film surface, while feeling carefully for any foreign material which might influence the image. The experimenter moved the subject's fingertip to another portion of the film, again feeling for foreign material, and kept his hands near the subject's hands to detect any movement. The experimenter, subject and observers concentrated on the target image and, on the subject's command, one of the observers activated the camera. In one experiment one hundred healthy rats were distinguished from 100 rats who had cancerous tissues injected in their tails by the dramatic difference in corona emanation from their tails.