But now the molecules are dispersed, and so the energy is also dispersed throughout this larger region of space. Now, the protein molecules, even though they want to leave that bag, cannot leave that bag because of that physical barrier. They are simply too large to pass across those tiny pores in that semipermeable membrane. And so when we actually take out that bag, after the process, inside the bag, we're going to have very, very little of those tiny molecules. And so this means we're going to have a much pure sample of our protein than before. So this is the process of dialysis.