The causes of trance are mostly mental. Trance appears to be contagious. Viewed medically, it is seldom directly dangerous. It is a product of over-excitability, which time blunts. The disposition to trance is seldom manifested beyond a few months, or, at most, two or three years. For epilepsy is not a form of trance; it is, however, a mixed mental and spasmodic seizure, much allied to trance. Those who suffer from its attacks are found to be among the most susceptible of induced trance. But let me again ask, what then is trance? Trance is a peculiar mental seizure, (totally distinct from insanity, with which again, however, it may be combined,) the patient taken with which appears profoundly absorbed or rapt, and as if lost more or less completely to surrounding objects or impressions, or at all events to the ordinary mode of perceiving them; he is likewise more or less entirely lost to his former recollections. The mental seizures may or may not occur simultaneously or alternately with spasmodic seizures of any and every character. This definition of trance conveys, I am afraid, no very exact or distinct picture; but it is the definition of a genus, and a genus is necessarily an abstraction. However, it gives the features essential to all the forms of trance. A true general notion of trance can, indeed, only be realized by studying in detail each of the forms it includes. These are separated by the broadest colours. In the one extreme an entranced person appears dead, and no sign of life is recognisable in him; in the opposite, he appears to be much as usual, and perfectly impressible by any thing around him, so that it demands careful observation to establish that he is not simply awake. Then trance presents no fewer than five specific forms, distinguished each from the other by clear characters, their essential identity being established by each at times passing into either of the others. The terms by which I propose to designate the five primary forms of trance are—Death-trance, Trance-coma, Initiatory Trance, Half-waking-trance, Waking-trance. The five, however, admit, as I have before said, of being arranged in two groups: the first three forms enumerated constituting varieties of trance-sleep; the two latter constituting varieties of waking-trance. The next letter will treat of the first group; the two following will treat of the two varieties of the second.