Nowhere can the curious exaggeration and over-estimation of the real state of affairs in this field be better illustrated than in the popular impression as to the frequency in actual practice of "imaginary" diseases. Take the incidental testimony of literature, for instance, which is supposed to hold the mirror up to nature, to be a transcript of life. The pages of the novel are full, the scenes of the drama are crowded with imaginary invalids. Not merely are they one of the most valuable stock properties for the humorist, but whole stories and comedies have been devoted to their exploitation, like Moliere's classic "Le Malade Imaginaire," and "Le Medecin Malgre Lui." Generation after generation has shaken its sides until they ached over these pompous old hypochondriacs and fussy old dowagers, whose one amusement in life is to enjoy ill health and discuss their symptoms. They are as indispensable members of the _dramatis personae_ of the stock company of fiction as the wealthy uncle, the crusty old bachelor, and the unprotected orphan. Even where they are only referred to incidentally in the course of the story, you are given to understand that they and their kind furnish the principal source of income for the doctor; that if he hasn't the tact to humor or the skilled duplicity to plunder and humbug these self-made sufferers, he might as well retire from practice. In short, the entire atmosphere of the drama gives the strong impression that if people--particularly the wealthy classes--would shake themselves and go about their business, two-thirds of the illness in the world would disappear at once. Much of this may, of course, be accounted for by the delicious and irresistible attractiveness, for literary purposes, of this type of invalid. Genuine, serious illness, inseparable from suffering and ending in death, is neither a cheerful, an interesting, nor a dramatic episode, except in very small doses, like a well-staged death-bed or a stroke of apoplexy, and does not furnish much valuable material for the novelist or the play-writer. Battle, murder, and sudden death, while horrible and repulsive, can be contemplated with vivid, gruesome interest, and hence are perfectly available as interest producers. But much as we delight to talk about our symptoms, we are never particularly interested in listening to those of others, still less in seeing them portrayed upon the stage. On account of their slow course, utter absence of picturesqueness, and depressing character, the vast majority of diseases are quite unsuitable for artistic material. In fact, the literary worker is almost limited to a mere handful, at one extreme, which will produce sudden and dramatic effects, like heart failure, apoplexy, or the ghastly introduction of a "slow decline" for a particularly pathetic effect; and at the other extreme, those imaginary diseases, migraines and vapors, which furnish amusement by their sheer absurdity.