“In point of conscience, no more unexceptionable narrator, than the venerable Irish Clergyman who has given me this paper, on Mr. Barton’s case, could have been chosen. The statement is, however, medically imperfect. The report of an intelligent physician, who had marked its progress, and attended the patient, from its earlier stages to its close, would have supplied what is wanting to enable me to pronounce with confidence. I should have been acquainted with Mr. Barton’s probable hereditary pre-dispositions; I should have known, possibly, by very early indications, something of a remoter origin of the disease than can now be ascertained. “In a rough way, we may reduce all similar cases to three distinct classes. They are founded on the primary distinction between the subjective and the objective. Of those whose senses are alleged to be subject to supernatural impressions—some are simply visionaries, and propagate the illusions of which they complain, from diseased brain or nerves. Others are, unquestionably, infested by, as we term them, spiritual agencies, exterior to themselves. Others, again, owe their sufferings to a mixed condition. The interior sense, it is true, is opened; but it has been and continues open by the action of disease. This form of disease may, in one sense, be compared to the loss of the scarf-skin, and a consequent exposure of surfaces for whose excessive sensitiveness, nature has provided a muffling. The loss of this covering is attended by an habitual impassability, by influences against which we were intended to be guarded. But in the case of the brain, and the nerves immediately connected with its functions and its sensuous impressions, the cerebral circulation undergoes periodically that vibratory disturbance, which, I believe, I have satisfactorily examined and demonstrated, in my MS. Essay, A. 17. This vibratory disturbance differs, as I there prove, essentially from the congestive disturbance, the phenomena of which are examined in A. 19. It is, when excessive, invariably accompanied by _illusions_. “Had I seen Mr. Barton, and examined him upon the points, in his case, which need elucidation, I should have without difficulty referred those phenomena to their proper disease. My diagnosis is now, necessarily, conjectural.” Thus writes Doctor Hesselius; and adds a great deal which is of interest only to a scientific physician. The Narrative of the Rev. Thomas Herbert, which furnishes all that is known of the case, will be found in the chapters that follow. CHAPTER I. FOOT-STEPS. I was a young man at the time, and intimately acquainted with some of the actors in this strange tale; the impression which its incidents made on me, therefore, were deep, and lasting. I shall now endeavour, with precision, to relate them all, combining, of course, in the narrative, whatever I have learned from various sources, tending, however imperfectly, to illuminate the darkness which involves its progress and termination.