Alright, well you know that all saturated solute systems are systems under equilibrium. THat is, for a solution which has been saturated to the point where there is leftover solid, the rate at which the the solid is falling out of the solution is equal to the rate at which the the solid is dissolving into the water.
For example, let us consider a lead nitrate solution which has been supersaturated, with a substantial amount of lead nitrate crystals still undissolved. Now, if we were to add RADIOACTIVE lead nitrate crystals into our beaker, we get interesting results. Note at this point, only the added crystals are radioactive, not the initial solution. But if you wait a while and take a sample of the supernatant solution, you find that the solution has also become radioactive (it emits beta particles). If you repeat this after 3 hours, then again after 3 hours, etc, you find that at all these times the same amount of radiation is observed. This demonstrates that there are both forward and backward reactions taking place (some of the initially clean dissolved lead nitrate must have precipitated out, and some radioactive lead nitrate must have dissolved in). And the constancy of the radiation detected shows that the reactions proceed at the same rate once equilibrium has been achieved - which im sure lies far to the right!