of sleep, with our present faculties; and all, whose bodies and minds are tolerably active, will probably agree, that, independently of habit, a perpetual alternation of eight hours up, and four in bed, would employ the human powers less advantageously and agreeably, than an alternation of sixteen and eight. A creature which could employ the full energies of his body and mind uninterruptedly for nine months, and then take a single sleep of three months, would not be a man.

"This view," he afterward adds, “ agrees with the opinion of some of the most eminent physiologists. Thus Cabanis notices the periodical and isochronous character of the desire to sleep, as well as of other appetites. He states also, that sleep is more easy and more salutary, in proportion as we go to rest, and rise every day at the same hour; and observes, that this periodicity seems to have a reference to the motions of the solar system."

All this leads to the conclusion, that the correspondence thus obvious between the laws of the material world, and the constitution of man, and other animals, is not fortuitous, but is the appointment of a Wise Contriver, and manifests a designing First Cause.

THIRTEENTH WEEK-THURSDAY.

SLEEP.

WE have already taken notice of the dormant state of some animals, and even plants, in winter, as an instance of wise and beneficent design; but there is another state of somnolency, more frequent in its occurrence, and more limited in its duration, to which I shall now direct the attention of my readers; I mean that condition of the body to which we familiarly give the name of Sleep.

The remarkable manner in which the constitution of plants and animals is adapted to the length of the day,

was yesterday commented on; and one of the most striking of these adaptations is the provision by which man, and many of the lower animals, drop into a state of inactivity and sweet oblivion during the night.

The presence of light is necessary to enable creatures constituted as we are, to prosecute useful labours; but constant toil wears out the frame, and a period of rest is necessary. There is, therefore, an arrangement of our ever-provident Creator; by which light shall be, for a time, withdrawn from us, that we may be compelled, by a natural necessity, to refrain, at regulated and short intervals, from the prosecution of labours in which we might otherwise be too eagerly engaged. This is the point of view in which the subject has been already considered. Let us now attend to the subject in another light. Looking at the fact, that the earth is made to revolve on its axis once every twenty-four hours, and that thus its inhabitants are deprived of its light, and other genial influences, for nearly the half of that time, on an average, each day, What is the contrivance by which this natural occurrence is rendered agreeable and salutary? The reply is, that a provision is made by which the active powers both of body and mind are suspended, and sleep is induced.

And what is sleep? There is something very mysterious in this state, considered as a physiological phenomenon; but this inquiry does not fall under our present plan; and, if it did, we should probably find it difficult to come to any satisfactory conclusion as to its efficient cause, or the nature of the physical change in the nervous system, by which it is produced. We know it is a fact in the constitution of living beings; and this is all that it seems necessary, at present, to say on the subject. To define sleep, according to its actual appearances, is sufficiently easy. In attending to our own experience, in regard to its approach and actual occurrence, we discover that the will seems gradually to become enfeebled in its power over both the bodily and mental operations;

that the body becomes as it were benumbed, and ceases to receive impressions of external objects; and that the faculty of thought seems to wander without controul. In the functions which serve for the support of life, on the contrary, there is no material interruption. All of them remain unsuspended, and some of them are maintained in full vigour and activity. The natural actions of respiration, circulation, and digestion, are little affected. The powers, which are merely mechanical or chemical, seem to proceed in the usual manner; and, whatever internal stimuli are necessary for keeping them in action, retain their sensibility. It is otherwise with the different senses. These fall into a state of obtuseness and relaxation, from which they are not easily roused, though the possibility of affecting them, even without putting an end to the state of sleep, is a matter of daily experience; and, indeed, the fact that a sleeper can be awaked at all, through the medium of his sense of hearing, or of touch, or of sight, or even of taste or smell, is a sufficient proof that these faculties are not completely suspended. Neither is there a suspension of the mental powers. Our thoughts succeed each other with inconceivable rapidity, and the imagination appears often to be peculiarly awake and brilliant. It is the power of volition alone, so far as the mind is concerned, which has ceased to be exerted. This is usually attended with a relaxation of the voluntary muscles, which occasions a total want of power in all the parts of the body over which these muscles have control. I mention this, however, only as the usual condition of persons in a state of somnolency; for it is one of the remarkable phenomena of dreaming, to which we shall have occasion afterward to advert, that the mind does then frequently exert an influence, of a very extraordinary nature, over the bodily functions. There is something at once interesting and strange in this state, which its familiar occurrence causes us too often to lose sight of; but I must at present confine myself to a single observation. It is an essential

characteristic of sleep, that, so far from being able to induce it when we please, the anxiety to obtain this refreshment only drives it away from us; and it is not till we cease to think about it, that it steals on us. This is doubtless a wise provision; but then, were it to invade our body and mind not only unsolicited, but unexpected, and were we unable, to any extent, to counteract its approaches, very distressing effects might be produced. Attend to this for a moment. If we were to drop asleep, without warning, in the midst of some active operation, it is easy to see how many daily occurrences, of the most disastrous nature, would ensue. Struck by the unexpected visitant, the seaman, as he ascended the top-mast, or clung on the yard-arm, would relax his grasp, and be plunged into the sea, or dashed to pieces on the deck. The coachman, in the middle of his stage, would drop his reins, and fall senseless from his box. The builder would tumble with his trowel from the wall. The porter would fall paralyzed under his burden. The orator in the senate, at the bar, or in the pulpit, would falter, and sink with the unfinished sentence on his lips; and, in one, the fire of his patriotism; in another, the acuteness of his reasoning, or adroitness of his statement; and, in a third, an exhibition of the high and holy doctrines of the Gospel, or of impassioned eloquence in a heart full of zeal, or of the tender touches of Christian love, would ludicrously expire in a sudden drawl, a closing eye, and a countenance in an instant relaxed into an expression of drowsy insensibility. Or rather, almost all these active and useful operations, and indeed most of the important business of life, would be prevented by the anticipation of so inconvenient and dangerous a catastrophe.

It is, therefore, no slight proof of the wisdom of the Divine Contriver, that, while he has rendered sleep a necessary function, superior to the human will, he has, at the same time, afforded such indications of its approach, as to allow man time and opportunity decently to compose his limbs, and has even bestowed upon him

such power of temporary counteraction, especially in seasons of active exertion, as to enable him to carry on his operations for a considerable period, without serious inconvenience, or fear of interruption, by the unwelcome and deathlike intruder.

THIRTEENTH WEEK-FRIDAY.

DREAMING.

THE phenomena of dreaming, which are so remarkable, and in some respects so inexplicable, seem to have been afforded by Providence, as a kind of agreeable relaxation to the ever active powers of the mind, while the bodily functions are in a state of necessary repose.

The subject has attracted deep attention from the earliest times, and has given rise to views and theories of very different kinds, corresponding either with the prepossessions of a particular age, or with the speculative views of the individuals by whom it has been treated. In early times, when a miraculous intercourse was kept up between heaven and earth, in preparing the world for the reception of the Saviour, dreams were frequently employed as the medium of that intercourse; and it was perhaps owing to these real events, that a superstitious veneration for dreams was cherished, even in the most polished ages of the ancient world. The Greeks and Romans divided the action of the mind, in sleep, into five sorts, the dream, the vision, the oracle, the insomnium, and the phantasm, of which the three first were supposed to be divinely inspired. To such height had the superstitious feeling with regard to dreams arisen, in Rome, in the age of Augustus Cæsar, that this monarch procured the passing of a law obliging all who had dreamed any thing respecting the state, to make it publicly known;