If the physician is sometimes fooled, how much more the sufferer himself? Nausea from a healthy stomach is just as sickening as nausea from a diseased one. A fainting-spell is equally uncomfortable, whether it comes from an impaired heart or simply from one that is behaving badly for the moment. It must be remembered that in functional nervousness the trouble is very real. The organs are really "acting up." Sometimes it is the brain that misbehaves instead of the stomach or heart. In that case it often reports all kinds of pains that have no origin outside of the brain. Pain, of course, is perceived only by the brain. Cut the telegraph wire, the nerve, and no amount of injury to the finger can cause pain. It is equally true that a misbehaving brain can report sensations that have no external cause that have not come in through the regular channel along the nerve. The pain feels just the same, is every bit as uncomfortable as though its cause were external.