fufpend the power of volition, but to fufpend the exertion of thofe powers whofe exercise depends on volition. If it were neceffary that volition should be suspended before we fall asleep, it would be impoffible for us, by our own efforts, to haften the moment of reft. The very fuppofition of fuch efforts is abfurd; for it implies a continued will to fupend the acts of the will. According to the foregoing doctrine with refpect to the state of the mind in fleep, the effect which is produced on our mental operations, is ftrikingly analogous to that which is produced on our bodily powers. From the obfervations which have been already made, it is manifeft, that in fleep, the body is, in a very inconfiderable degree, if at all, fubject to our command. The vital and involuntary motions, however, fuffer no interruption, but go on as when we are awake, in confequence of the operation of fome cause unknown to us. In like manner, it would appear, that thofe operations of the mind which depend on our volition are fufpended; while certain other operations are, at leaft, occafionally, carried on. This analogy naturally fuggefts the idea, that all our mental operations, which are independent of our will, may continue during fleep; and that the phenomena of dreaming may, perhaps, be produced by thefe, diverfified in their apparent effects, in confequence of the fufpenfion of our voluntary powers. If the appearances which the mind exhibits during fleep, are found to be explicable on this general principle, it will poffefs all the evidence which the nature of the fubject admits of. It was formerly fhewn, that the train of thought in the mind does not depend immediately on our will, but is regulated by certain general laws of affocia tion. At the fame time, it appeared, that among the various fubjects which thus fpontaneously prefent themselves to our notice, we have the power of fingling out any one that we chufe to confider, and of inaking it a particular object of attention; and that by doing fo, we not only can stop the train that would otherwife have fucceeded, but frequently can divert the current of our thoughts into a new channel. It alfo appeared, that we have power (which may be much improved by exercife) of recalling palt occurrences to memory, by a voluntary effort of recollection. The indirect influence which the mind thus poffeffes over the train of its thoughts is fo great, that during the whole time we are awake, excepting in thofe cafes in which we fall into what is called a reverie, and fuffer our thoughts to follow their natural course, the order of their fucceffion is always regulated more or lefs by the will. The will, indeed, in regulating the train of thought, can operate only (as I already fhewed) by availing itself of the established laws of affociation; but ftill it has the power of rendering this train very different from what it would have been, if thefe laws had taken place without its interference. From these principles, combined with the general fact which I have endeavored to establish, with refpect to the state of the mind in fleep, two obvious confequences follow: First, That when we are in this fituation, the fucceffion of our thoughts, in fo far as it depends on the laws of affociation, may be carried on by the operation of the fame unknown caufes by which it is produced while we are awake; and, Secondly, that the order of our thoughts, in these two states of the mind, must be very different; inafmuch as, in the one, it depends folely on the laws of affociation; and in the other, on these laws, combined with our own voluntary exertions. In order to afcertain how far thefe conclufions are agreeable to truth, it is neceffary to compare them with the known phenomena of dreaming. For which purpose, I fhall endeavor to fhew, Firft, That the fucceffion of our thoughts in fleep, is regulated by the fame general laws of affociation, to which it is fubjected while we are awake; and, Secondly, That the circumftances which difcriminate dreaming from our waking thoughts, are fuch as muft neceffarily arife from the fufpenfion of the influence of the will. I. That the fucceffion of our thoughts in fleep, is regulated by the fame general laws of affociation, which influence the mind while we are awake, appears from the following confiderations. 1. Our dreams are frequently fuggefted to us by bodily fenfations: and with thefe, it is well known, from what we experience while awake,that particular ideas are frequently very ftrongly affociated. I have been told by a friend, that having occafion, in confequence of an indifpofition, to apply a bottle of hot water to his feet when he went to bed, he dreamed that he was making a journey to the top of Mount Etna, and that he found the heat of the ground almoft infupportable. Another person, having a blifter applied to his head, dreamed that he was fcalped by a party of Indians. I believe every one who is in the habit of dreaming, will recollect inftances, in his own cafe, of a fimilar nature. 2. Our dreams are influenced by the prevailing temper of the mind; and vary, in their complexion, according as our habitual difpofition, at the time, inclines us to cheerfulness or to melancholy. Not that this obfervation holds without exception; but it holds fo generally, as must convince us, that the ftate of our fpirits has fome effect on our dreams, as well as on our waking thoughts. Indeed, in the latter cafe, no less than in the former, this effect may be counteracted, or modified, by various other cir cumftances. After having made a narrow efcape from any alarming danger, we are apt to awake, in the courfe of our fleep, with fudden startings; imagining that we are drowning, or on the brink of a precipice. A fevere misfortune, which has affected the mind deeply, influences our dreams in a fimilar way; and fuggefts to us a variety of adventures, analogous, in fome measure, to that event from which our distress arifes. Such, according to Virgil, were the dreams of the forfaken Dido. Agit ipse furentem, "In somis ferus Eneas; semperque relinquí, 8. Our dreams are influenced by our prevailing habits of affociation while awake. In a former part of this work, I confidered the extent of that power which the mind may acquire over the train of its thoughts; and I obferved, that those intellectual diverfities among men, which we commonly refer to peculiarities of genius, are, at leaft in a great measure, refolvable into differences in their habits of affociation. One man poffeffes a rich and beautiful fancy, which is at all times obedient to his will. Another poffeffes a quickness of recollection, which enables him, at a moment's warn ing, to bring together all the refults of his past experience, and of his paft reflections, which can be of ufe for illuftrating any propofed fubject. A third can, without effort, collect his attention to the most abftract queftions in philofophy; can perceive, at a glance, the fhorteft and the most effectual process for arriving at the truth; and can banifh from his mind every extraneous idea, which fancy or cafual affociation may fuggeft, to distract his thoughts, or to miflead his judgment. A fourth unites all thefe powers in a capacity of perceiving truth with an almost intuitive rapidity; and in an eloquence which enables him to command, at pleasure, whatever his memory and his fancy can fupply, to illuftrate and to adorn it. The occafional exercife which fuch men make of their powers, may undoubtedly be faid, in one sense, to be unpremeditated or unftudied; but they all indicate previous habits of meditation or ftudy, as unquestionably, as the dexterity of the expert accountant, or the rapid execution of the profeffional musician. From what has been faid, it is evident, that a train of thought which, in one man, would require a painful effort of study, may, in another, be almoft fpontaneous; nor is it to be doubted, that the reveries of ftudious men, even when they allow, as much as they can, their thoughts to follow their own course, are more or lefs connected together by those principles of affociation, which their favorite pursuits tend more particularly to ftrengthen. The influence of the fame habits may be traced distinctly in fleep. There are probably few mathematicians, who have not dreamed of an interefting problem, and who have not even fancied that they were profecuting the investigation of it with much fuccefs. They whofe ambition leads them to the study of eloquence, are frequently conscious, during fleep, of a renewal of their daily occupations; and fometimes feel themselves poffeffed of a fluency of fpeech, which they never experienced before. The Poet, in his dreams, is tranfported into Elyfium, and leaves the vulgar and unfatisfactory enjoyments of humanity, to dwell in those regions of enchantment and rapture, which have been created by the divine imaginations of Virgil and of Taffo. "And hither Morpheus sent his kindest dreams, Oo |