It is well known, that maniacs often suppose they have seen and heard those things, which really did not exist at the time; but even this I should not explain by any disability, or error of the perception; since it is by no means the province of the perception to represent unreal existences to the mind. It must therefore be sought elsewhere; most probably in the senses. We sometimes (more especially in the early stages of furious madness) find patients from very slight resemblances, and sometimes, where none whatever can be perceived by others of sound mind, confounding one person with another. Even in this case it does not seem necessary to recur to false perception for the explanation. It is equally probable that the organs of vision are affected in consequence of the disease of the brain, and therefore receive incorrect sensations: and still more likely, from the _rapid succession_ in which objects are noticed, that a very slight trait of countenance would recal the idea [or name] of some particular person. I have known many cases of patients who insisted that they had seen the devil. It might be urged, that in these instances, the perception was vitiated; but it must be observed there could be no perception of that, which was not present and existing at the time. Upon desiring these patients to describe what they had seen, they all represented him as a big, black man, with a long tail, and sharp talons, such as is seen pictured in books; a proof that the idea was revived in the mind from some former impressions. One of these patients however carried the matter a little further, as she solemnly declared, she heard him break the iron chain with which God had confined him, and saw him pass fleetly by her window, with a truss of straw upon his shoulder. That "confusion of ideas" should be the necessary consequence of false perception, is very difficult to admit. It has often been observed that madmen will reason correctly from false premises, and the observation is certainly true: we have indeed occasion to notice the same thing in those of the soundest minds. It is very possible for the perception to be deceived in the occurrence of a thing, which, although it did not actually happen, yet was likely to take place; and which had frequently occurred before.--The reception of this as a truth, if the person were capable of deducing from it the proper inferences, could neither create confusion nor irregularity of ideas.