And what the basic fields also do is they also release that histamine. So the histamine causes the dilation of blood vessels leading to that infected area and that is why we have this area of redness along our cut because the redness is caused by the flow of blood into that infected area. Now the capillaries are also affected as a result of that histamine and the capillaries in that infected area essentially become more leaky, become more permeable to that water, to that blood plasma and this ultimately causes the process of swelling which we call edema. Now, why would we actually want to increase the blood flow to that infected area? Well for one thing we want to bring those special immune cells that are responsible for killing off those bacterial agents, those pathogens. And another thing we also want to bring the nutrients to that area because those cells in that tissue will be working harder.