is quickly communicated to the whole system, and probably is the principal cause of the final solution of the paroxysm. How this solution is at length effected is, I confess, a difficult and obscure question. There are two ways in which it takes place; the first and most frequent is by the patient becoming perfectly awake, by which means he recovers at once the power of volition, and the partial paralysis of the diaphragm and thoracic muscles at the same moment ceases, these muscles being then moved by the power of the will. The other mode by which a solution of the paroxysm is effected, is by the patient falling into a more perfect sleep, and losing that consciousness which accompanies Night-Mare. The involuntary actions then go on as before without interruption, and if the dreams continue, they are no longer of that harassing and distressing kind, but are now natural and easy. It is not only in slight cases of Incubus that the patient recovers from the disease without waking, but sometimes I have known it to happen even in very severe paroxysms, where I have become conscious of the place and situation in which I was, and yet have instantly been asleep on the cessation of the paroxysm. There appears to me a greater difficulty in explaining this mode of the solution of the paroxysm than the other, as there seems no evident cause for the cessation of the paralysis of the Diaphragm, &c. Every thing connected with the phenomena of sleep, is extremely obscure; and nothing on this subject appears to me more extraordinary, than the sudden transition from the sleeping to the waking state. Whatever it is which takes place at that moment in the brain, and in the whole system, takes place only partially during Night-Mare. Is it very absurd to suppose that a part of the system may recover the waking state, while the brain, or some other part, remains asleep, for want of a sufficient stimulus to rouse them? I cannot help thinking but something very similar to this takes place in Night-Mare: hence the power of moving the lower extremities, whilst the superior ones remain paralyzed: hence the little good resulting to the patient from his own struggling, whilst a comparatively slight touch from another person is sufficient to dispel the charm. Hence the appearance of visions, whilst in every respect the patient appears to himself to be perfectly awake. It seems that the brain continues to present a succession of images to the mind as in sleep, whilst at the same time, the body is become susceptible of external impressions, and conscious of internal ones, such as those arising from the derangement which has taken place in the functions of the heart and lungs.