of repose, and have suffered more from its repeated attacks than any other person I have ever met with, I hope to be able to throw some light on the nature of this affection, and to point out some mode of relief to the unfortunate victims of it. The late Dr. Darwin, who had an admirable talent for explaining the phenomena of animal life in general, is of opinion, that this affection is nothing more than sleeping too sound; in which situation of things the power of volition, or command over the muscles of voluntary motion, is too completely suspended; and that the efforts of the patient to recover this power, constitute the disease we call Night-Mare. In order to reconcile this hypothesis with the real state of things, he is obliged to have recourse to a method not unusual amongst theoretic philosophers, both in medicine and other sciences--that is, when the hypothesis does not exactly apply to the phenomenon to be explained by it, to twist the phenomenon itself into such a shape as will make it fit, rather than give up a favourite hypothesis. Now, in order to mould the Night-Mare into the proper form, to make this hypothesis apply to it, he asserts, first, that it only attacks persons when very sound asleep; and secondly, that there cannot exist any difficulty of breathing, since the mere suspension of volition will not produce any, the respiration going on as well asleep as awake; so that he thinks there must needs be some error in this part of the account. Any person, however, that has experienced a paroxysm of Night-Mare, will be disposed rather to give up Dr. Darwin’s hypothesis than to mistrust his own feelings as to the difficulty of breathing, which is far the most terrific and painful of any of the symptoms. The dread of suffocation, arising from the inability of inflating the lungs, is so great, that the person, who for the first time in his life is attacked by this “worst phantom of the night,” generally imagines that he has very narrowly escaped death, and that a few seconds more of the complaint would have inevitably proved fatal. This disease, although neglected by modern physicians, was well described and understood by those of the seventeenth century, as well as by the Greeks and Romans.[1] There are few affections more universally felt by all classes of society, yet it is seldom at present considered of sufficient consequence to require medical advice. To those nevertheless who, from sedentary habits, and depraved digestion, are the most frequent subjects of it, it is a source of great anxiety and misery, breaking in upon their repose, and filling the mind with constant alarms for more serious consequences, “making night hideous,” and rendering the couch, which is to others the sweet refuge from all the cares of life, to them an object of dread and terror. To such persons, any alleviation of their sufferings will be considered an act of philanthropy; as they are now in general only deterred from applying to the