Well, the answer lies in the following idea. Recall what the function of the loop of Henley was in our discussion on the countercurrent multiplier system and the loop of Henley. We basically said that what the loop of Henley does is it creates a high concentration of ions of solute ions in the interstituum of aramidoula. In fact, as we go lower along aramidoula, as we go deeper into aramidoula, the concentration of ions increases. Now, if we have a higher concentration of ions outside in the surrounding tissue than in the inside of the lumen of our collecting duct, then water will tend to flow from a lower concentration of solute to a higher concentration of solute. And that's because the sommotic pressure on the outside will be higher.