are never so blind from that cause but that they can discern day from night, and, for the most part, in a strong light, distinguish black, white, and scarlet: but they can not perceive the shape of any thing; for the light by which these perceptions are made, being let in obliquely through the aqueous humor, or the anterior surface of the crystaline humor, by which the rays can not be brought into a focus upon the retina, they can discern in no other manner than a sound eye can through a glass of broken jelly, where a great variety of surfaces so differently refract the light, that the several distinct pencils of rays can not be collected by the eye into their proper foci; wherefore the shape of an object in such a case can not be discerned at all, though the color may and thus it was with this young gentleman, who, though he knew those colors asunder, in a good light, yet, when he saw them after he was couched the faint ideas he had of them before, were not sufficient for him to know them by afterward; and therefore he did not think them the same which he had before known by those names.

When he first saw, he was so far from making any judgment about distances, that he thought all objects whatever touched his eyes (as he expressed it), as what he felt did his skin; and thought no objects so agreeable as those which were smooth and regular, though he could form no judgment of their shape, or guess what it was in any object that was pleasing to him. He knew not the shape of any thing, nor any one thing from another, however different in shape or magnitude; but upon being told what things were whose form he before knew from feeling, he would carefully observe that he might know them again; but having too many objects to learn at once, he forgot many of them, and (as he said) at first learned to know, and again forget, a thousand things in a day. One particular only, though it may appear fling, I will relate. Having often forgot which was the cat and which the dog, he was ashamed to ask; but catching the cat (which he knew by feeling), he was observed to look at her steadfastly, and then, setting her down, said, 'So, Puss! I shall know you another time.' "We thought he soon knew what pictures represented

tri

which were shown him; but we found afterward we were mistaken, for, about two months after he was couched, he discovered at once they represented solid bodies, when to that time he considered them only as party-colored planes, or surfaces diversified with variety of paints: but even then, he was no less surprised, expecting the pictures would feel like the things they represented; and was amazed when he found those parts which, by their light and shadow, appeared now round and uneven, felt only flat like the rest, and asked which was the lying sense, feeling or seeing.

"In a year after seeing, the young gentleman being carried upon Epsom Downs, and observing a large prospect, he was exceedingly delighted with it, and called it a new kind of seeing."

FRAGMENT OF LECTURE V.

ON CONCEPTION.

*

before the

mind can gaze upon the scene with any portion of tranquillity and composure. This mistake of conception for sensation is also the best key to the phenomena observed in madness. A madman has the conception of all the pageantry of a court, and so may any man in his senses; the difference is, the one knows it to be only a creation of his mind, the other really believes he sees dukes, and marquises, and all the splendor of a real court. If he is not very far gone, he pays some attention to the objects of sense about him, and tells you that he is confined in this sorry situation by the perfidy and rebellion of his subjects. As the disease further advances, he totally neglects the objects of his senses;-does not see that he sleeps on straw and is chained down, but abandons himself wholly to the creations of his mind, and riots in every extravagance of thought. This, though by far the most common species of insanity, is not the only one. There are some persons quite rational in their perceptions, who are considered as deranged only from a morbid association of ideas; as in the instance of the patient mentioned in Mr. Haslam's book, who persevered in a vegetable diet because, he said, roast and boiled meat felt the most exquisite pain while any person was devouring them.

The mistaking of conceptions for sensations appears also to be the proper explanation of what passes in our minds during sleep. To consider sleep aright, we must divide it into stages. In profound sleep, there is no

evidence that we think at all. When we have been exhausted with great fatigue or acute pain, we often lie motionless for hours, without the smallest recollection that a single idea has passed through our minds: the periods of sleeping and waking appear to be consecutive instants of time. In this state of sleep it seems as if every operation of the mind were entirely suspended; and in the instance of those who have taken quantities of opium, or become drowsy from long journeys over snow, it seems to have a great tendency to death. We frequently dream in our sleep without recollecting the slightest feature of our dreams when we wake. It would appear at first, that processes of thought which have made such faint impressions on the memory must have been the slightest and most disconnected of all dreams; and yet the most rational and systematic dreamers-those who walk in their sleep-have seldom or ever the most distant recollection that they have been dreaming at all.

In the common state of sleep, where we dream without stirring, or, at least, without walking about, there seems to be, first, a great diminution of the power of the will over the body, but by no means a total suspension of that power for a person much agitated in his dreams can cry out, and therefore subject the organs of speech to his will; or he can toss about his hands and feet, and so subject those parts of his body to his will; but, however, the influence of the will upon the body, though not wholly suspended, is certainly considerably weakened. In this sort of sleep it is still less suspended over the mind, for a man makes a bargain in his dreams, and examines the terms of the bargain, and dwells upon one part of it with some accuracy; he argues in his sleep, not merely repeating, as has been said, arguments which have occurred to him in his waking hours, but inventing new ones, with some pains and attention. I mention these circumstances in opposition to those who have contended that the influence of the will is entirely suspended in sleep. I should think diminished would be a better word,-for suspended it certainly is not in the body, and still less so in the mind; though its power

is incomparably less than in our waking hours. But the most striking phenomenon in our sleep is that which I have shown to take place in madness-the confusion between our sensations and conceptions. I may think when I am awake of a chariot drawn by tigers; but I know then, it is merely a thought. When I am in a revery, I am in a confused state between doubt and belief of its existence. When I am asleep, I take this thought for a reality; and as our sensations follow one another in a regular and established order, and our conceptions are very loosely connected together, this is the reason of all the absurdity and incongruity of our dreams. Indeed, sense and nonsense, congruity and incongruity, are only determined by the outer world; and we consider our conceptions to be wild or rational only as they correspond with it.

According as sleep is more or less perfect, sensations do or do not produce an effect upon the mind, exactly the same as in revery or in madness. A person may, in some cases, sleep so soundly, that the firing a pistol close to his ear will not rouse him;-at other times the slightest sensation of light or noise will rouse him. A sort of intermediate state between these two is that where the sensation comes to the mind in so imperfect a state, that it produces some effect upon the current of conceptions without correcting them. If there is a window left open, and the cold air blows in, the sufferer may think himself on the top of Mount Caucasus, buried in the snow; or the cat making a noise shall immediately transport him in imagination to the Opera.

The most singular phenomenon respecting sleep is somnambulism, or walking in the sleep. The instances are innumerable of men who have walked along the ridges of houses in their sleep; have got up, dressed themselves, taken pen, ink, and paper, have written very rationally and connectedly, and acted precisely as they would have done had they been awake. Out of this mass of histories I shall make a short extract from a well-authenticated one, reported by a Physical Society at Lausanne. It is the case of Devaux, a lad about thirteen years of age, who lived in the town of Vevay.