Abscesses occur when an area of tissue becomes infected and the body's immune system tries to fight it. White blood cells move through the walls of the blood vessels into the area of the infection and collect within the damaged tissue. During this process, pus forms.
cognition cogÂ·niÂ·tion (kÅg-nÄ­sh'Én) n. The mental faculty of knowing, which includes perceiving, recognizing, conceiving, judging, reasoning, and imagining.
1 an immediate cognition of an object not inferred or determined by a previous cognition of the same object. 2  any object or truth so discerned.  pure, untaught, noninferential knowledge.