So prone is a lively imagination to a derangement of the intellectual harmony, that the greatest care should be taken during the youthful development to resort to a sound and proper exercise. The constant tendency to wild and supernatural visions, the disregard of every daily and vulgar matter of fact consideration, soaring in regions of fiction, should engage our incessant vigilance, such a state of mind, as Abercrombie justly observes, "tends in a most material manner to prevent the due exercise of those nobler powers which are directed towards the cultivation both of science and of virtue," and Foster has thus beautifully illustrated this subject in his essays. "The influence of this habit of dwelling on the beautiful fallacious forms of imagination, will accompany the mind into the most serious speculations or rather musings, on the real world, and what is to be done in it and expected; as the image which the eye acquires from looking at any dazzling object, still appears before it wherever it turns. The vulgar materials, that constitute the actual economy of the world, will rise up to its sight in fictitious forms, which it cannot disenchant into plain reality, nor will ever suspect to be deceptive. It cannot go about with sober, rational inspection and ascertain the nature and value of all things around it--in that paradise it walks delighted, till some imperious circumstance of real life call it thence, and gladly escapes thither again when the avocation is past. If a tenth part of the felicities that have been enjoyed, the great actions that have been performed, the beneficial institutions that have been established, and the beautiful objects that have been seen in that happy region, could have been imported into this terrestial place!--what a delightful thing the world would have been to awake each morning to see such a world once more!" Of the miseries the hypochondriacs experience the following extract of a letter to a physician will afford a specimen: "My poor body is a burning furnace, my nerves red-hot coals, my blood is boiling oil; all sleep has fled, and I am suffering martyrdom. I am in agony when I lie on my back; I cannot lie on either side; and I endure excruciating torture when I seek relief by lying on my stomach; and, to add to my misery, I can neither sit, stand, nor walk." The fancies of hypochondriacs are frequently of the most extraordinary nature: one patient imagines that he is in such a state of obesity as to prevent his passing through the door of his chamber or his house; another impressed with the idea that he is made of glass, will not sit down for fear of cracking; a third seems convinced that his head is empty; and an intelligent American, holding a high judicial seat in our West Indian colonies, could not divest himself of the occasional conviction of his being transformed into a turtle.