Does anyone know the answer to this old saw? Is it really true what you've seen in a hundred old westerns, where a parched cowboy lives to fight another day by drinking from a cactus? Can you really cut one open and drink its juice to stay alive if you're lost in the desert and out of water? I've heard that the juice--if there is any--is too viscous to quench a thirst. (What brought this to mind was that I was watching a survival show, and the host created drinking water from his urine by building a solar still out of a sheet of plastic, a cup, a stick, and a few rocks.