Hot and cold tubbing offers a deeper and more extreme version of hot and cold showering and as such can effect a great deal of change within the body and really shift stagnation. Douglas Lewis (Basteur Institute, Seattle), observed that the H.I.V. virus was only able to sustain itself in low body temperatures and so adopted hot tubbing when treating Aids patients. Douglas Lewis elevates the temperature to 104˚F for one hour, twice a week. He found that sustained high temperatures would create artificial fever conditions that in turn created changes within the virus that rendered it non-viable.