Sensory Deprivation Tank

Sensory deprivation tank is a lightless, soundproof tank in which subjects float in salty water at skin temperature. It was developed 1954 by American physician John C. Lilly to test the effects of sensory deprivation. Such tanks are now also used for meditation and relaxation and in alternative medicine. There are potential health benefits such as:

- Speeded recovery from injury
- Reduced symptoms of such ailments as asthma, arthritis, bursitis, multiple sclerosis, migraine and tension headaches, fibromyalgia, insomnia, and rheumatoid arthritis
- Improved post-operative recovery

More extreme uses of the tank involve the subject taking varying doses of hallucinogens, such as LSD, and spending prolonged periods in the tank (up to tens of hours) at a time.

Sources and further reading:

Wikipedia on John C. Lilly and SDT

Altered States (a film featuring the tank)