dreamt that we have done so; and as I have said above, after some lapse of time we are not always able to distinguish between the two. While dreaming, we frequently ask ourselves whether we are awake or asleep; and nothing is more common than to hear people say, “Well, I think I did, or heard, so and so; but I am not sure whether it was so, or whether I dreamt it.” Thus, therefore, the very lowest order of dreaming, the most disjointed and perplexed, is far removed from the most vivid presentations of our waking thoughts; and it is in this respect, I think, that the explanations of the phenomena hitherto offered by phrenologists, and the metaphysicians of this country, are inadequate and unsatisfactory; while, as regards the analogy between the visions of sleep and delirium, whatever similarity there may be in the effects, we can not suppose the cause to be identical: since, in delirium the images and delusions are the result of excessive action of the brain, which we must conclude to be the very reverse of its condition in sleep. Pinel certainly has hazarded an opinion that sleep is occasioned by an efflux of blood to the head, and consequent compression of the brain—a theory which would have greater weight were sleep more strictly periodical than it is; but which, at present, it seems impossible to reconcile with many established facts. Some of the German physiologists and psychologists have taken a deeper view of this question of dreaming, from considering it in connection with the phenomena of animal magnetism; and although their theories differ in some respects, they all unite in looking toward that department of nature for instruction. While one section of these inquirers, the Exegetical Society of Stockholm included, calls in the aid of supernatural agency, another, among whom Dr. Joseph Ennemoser, of Berlin, appears to be one of the most eminent, maintains that the explanation of the mystery is to be chiefly sought in the great and universal law of polarity, which extends not only beyond the limits of this earth, but beyond the limits of this system, which must necessarily be in connection with all others; so that there is thus an eternal and never-ceasing inter-action, of which, from the multiplicity and contrariety of the influences, we are insensible, just as we are insensible to the pressure of the atmosphere, from its impinging on us equally on all sides.