Worry, in fact, is a sign of disease instead of a cause. To put it very crudely, whenever the blood and fluids of a body become impoverished below a certain degree, or become loaded with fatigue poisons, or other waste products above a certain point, then the nervous system proceeds to make itself felt. Either the perceptive end-organs become color-blind and read yellow for blue, or are astigmatic and report oval for round; or the conducting nerve-strands tangle up the messages, or deliver them to the wrong centre; or the central clearing-house, puzzled by the crooked messages, loses its head, and begins to throw the inkstands about, or goes down in a sulk. In other words, the nervous system goes on a strike. But it is perfectly idle to endeavor to treat it with cheering words, or kindly meant falsehoods, to the effect that "nothing is really the matter." Like any other strike, it can be rationally dealt with only by improving the conditions under which the operatives have to work, and meeting their demands for higher wages, or shorter hours. We were accustomed at one time to divide diseases into two great classes, organic and functional. By the former, we meant those in which there was some positive defect of structure, which could be recognized by the eye or the microscope; by the latter, those diseases in which this could not be discovered, in which, so to speak, the machine was all right, but simply wouldn't work. It goes without saying that the latter class was simply a confession of our ignorance, and one which is steadily and rapidly diminishing as science progresses. If the machine won't work, there is a reason for it somewhere, and our business is to find it out, and not loftily to assure our patients that there is nothing much the matter, and all they need is rest, or a little cheerful occupation. Furthermore, the most inane thing that a sympathizing friend or kindly physician can do to a neurasthenic, is to advise him to take his mind off himself or his symptoms. The utter inability to do that very thing is one of the chief symptoms of the disease, which will not disappear until the underlying cause has been carefully studied out and removed. "Nerves," "neurasthenia," "psychasthenia," and "hysteria," are all the names of _symptoms_ of _definite bodily disease_. The modern physician regards it as his duty to study out and discover the nature of this disease, and, if possible, remove it, rather than to give high-sounding, soul-satisfying names to the symptoms, and advise the patient to "cheer up"; which advice costs nothing--and is worth just what it costs.