So leukocytes, the white blood cells, are found circulating in the blood plasma in our lymph system and also inside our tissue. And actually, leukocytes are amoebilike cells. And what that means is leukocides can actually move independently of other cells and other structures inside our body. In fact, leukocytes can move against the flow of blood and the flow of lymph in our vessels, blood vessels and lymph vessels of our body. And that's important because leukocytes must be able to move from one location to different locations where that infection is actually taking place. Now, the way that the leukocytes actually move across the capillaries from the blood plasma to the tissue or in reverse, is via a process known as diapedesis.