Ghadiali's son, Darius Dinshah, continues to provide information about color therapy via his Dinshah Health Society, a nonprofit organization dedicated to advancing non-pharmaceutical home color therapy, and his book Let There Be Light. Science writer Martin Gardner had described Ghadiali as "perhaps the greatest quack of them all". According to Gardner, photographs of Ghadiali at work in his laboratory are "indistinguishable from stills of a grade D movie about a mad scientist". Throughout the 19th century "color healers" claimed colored glass filters could treat many diseases, including constipation and meningitis. Colored chakras Practitioners of ayurvedic medicine believe the body has seven "chakras", which some claim are 'spiritual centers', and are thought to be located along the spine. New Age thought associates each of the chakras with a single color of the visible light spectrum, along with a function and organ or bodily system. According to this view, the chakras can become imbalanced and result in physical and mental diseases, but application of the appropriate color can allegedly correct such imbalances. Scientific rejection Chromotherapy is regarded by health experts as quackery. According to a book published by the American Cancer Society, "available scientific evidence does not support claims that alternative uses of light or color therapy are effective in treating cancer or other illnesses". Photobiology, the term for the scientific study of the effects of light on living tissue, has sometimes been used instead of the term chromotherapy in an effort to distance it from its roots in Victorian mysticism and to strip it of its associations with symbolism and magic. Light therapy is a specific treatment approach using high intensity light to treat specific sleep, skin and mood disorders. A review of the existing research on chromotherapy found that there is no evidence to support a causal link between specific colors to health outcomes, there is not enough evidence to support a causal link between specific colors and emotional or mental states, and there is no research to suggest there exists one-to-one relationships between specific colors and emotions. Chromotherapy has been accused of oversimplifying psychological responses to colors, making sweeping statements based on myths or beliefs that lack empirical support. Guidelines for chromotherapy lack consistency and appear to be subjective judgements that have inconclusive and nonspecific applicability in healthcare systems. While twelve colors have been reported as beneficial for health and well-being, a rigorous definition of each of these colors