It must be acknowledged, that in the soundest state of our faculties we sometimes perceive things which do not exist. If the middle finger be crossed over the forefinger, and a single pea be rolled under their extremities, we have the perception of _two_. By immersing one hand into warm, the other into cold water, and afterwards suddenly plunging them both into the same fluid, of a medium temperature, we shall derive the sensations of heat, and cold from the same water, at the same time. The power, by which the mind perceives its own creations and combinations is perhaps the same, as that by which it perceives the impressions on the senses from external objects. We possess the faculty of raising up of objects in the mind which we had seen before, and of prospects, on which we had formerly dwelt, with admiration and delight; and in the coolest state of our understanding we can even conceive that they lie before us. If the power which awakens these remembrances in a healthy state of intellect, should stir up distorted combinations in disease, they must necessarily be perceived; but their apprehension, by no means appears to imply a vitiated state of the faculty by which they are perceived. In fact, that which is represented to the mind, either by a defect or deception of the senses, or by the imagination, if it be sufficiently forcible and enduring, must necessarily be perceived. That "confusion of ideas" should be the necessary consequence of false perception, is very difficult to admit. Perhaps much may depend, in the discussion of this point, on the various acceptations in which confusion of ideas may be understood. It has often been observed that madmen, will frequently 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 in the mind, if the power of deducing from it the proper inferences existed, could neither create confusion, nor irregularity of ideas. Melancholy, the other form in which this disease is supposed to exist, is made by Dr. Ferriar to consist in "intensity of idea." I shall shortly have an opportunity, in the definition I propose to give, of attempting to prove, that this division of Insanity, is neither natural nor just, upon the ground that the derangement is equally complete in both forms of the disease. We ought to attend more to the state of the intellect, than to the passions which accompany the disorder.