Whether my investigation of the order and relations of the phenomena in sleep and dreams has at all furthered the elucidation of them, I must leave my readers to determine.

LECTURE I.

OBJECTS of study may be arranged under two great divisions; one consisting of those which must be sought in a wide investigation of external nature; the other of such as are at all times, and in all places within our reach. The former are spread as far as our bodies, or our senses, aided, or unaided, can extend; the latter we carry about with us. The one class are objects of sensation, or outward observation; the other of consciousness and internal reflection;-the world without, and the world within; this embracing the workings of our minds, our emotions, sentiments, affections, and propensities; the other, all the domain of matter and its attributes,―all that exists, whether we are living to observe it or not. Reviewing these two classes, we cannot help being struck with the overflowing provision which they present to our mental cravings; for while, on the one hand, the perceptive faculties have unbounded and delightful exercise amid the sublime and beautiful objects which the Creator has presented to us, in what we call the realms of Natural History, and Physical Philosophy; on the other hand, when by accident confined to narrow limits of space, deprived of one of our senses, or excluded from the objects of these senses, as in the shades of night, or in the solitude of sickness or captivity, we may turn inwards the mental eye, and see the wonders which the same Almighty Hand has fashioned in the mind and heart of man.

B

Our present subject belongs in some measure to both of the departments of inquiry which I have thus briefly sketched; for our knowledge of it is in part derived from our own experience, and in part from our observation of it in other beings.

To know something of that condition in which we spend one-third of our lives, is not an unworthy inquiry. And yet the thought may at first occur to you,-What can be better known than sleep?—a thing of which we have all of us common experience. But simple and obvious as it may seem to be, we shall find that the more we investigate it, the more is it productive of topics for interesting and curious speculation, and of questions not very easily answered.

What is Sleep? If we attempt to define it in positive terms, we shall find ourselves insensibly wandering among those metaphorical descriptions familiar to us in the pages of the poets, instead of giving an accurate account of its phenomena; for in fact it is a negative state of the living body, and is only to be correctly represented by the enumeration of various actions which are wanting in that condition, and the presence of which renders a person awake. To sleep perfectly is,-not to see, not to hear, not to smell, not to taste, not to touch, not to speak, not to move; in short, not to exercise one of the faculties which characterize a human being or even an animal. Well, then, may sleep be called "the image of Death," "Death's brother," "so like death," says Sir T. Browne, solemnly, "that I dare not trust it without my prayers." So, too, it was described by Homer,

"Then gentle slumber on his eyelids fell,

That deep, sweet sleep, which death resembles well."

In the human body there are two great classes of vital