One cannot visit the wards of an asylum without realising that there are many types of mental disease, each with its own symptoms and physical signs, and that intercurrent and overlapping affections of the mind are especially common; thus, in maniacal excitement you may find delusions, in paranoia you find delusions with marked impairment of judgment, in general paralysis you get, in addition to physical signs, delusions, which vary from the facility of the early period to the more difficult mentation found in the advanced age, so that here we have three distinct types of disease, each of which may have delusions, and the delusions may all be of the exalted variety— the patients may consider themselves gods, kings, or mighty personages. The progress of research has had more difficulties to contend with in the subject of mind than in almost any other. It is a subject which is intangible, yet its reactions can be timed. It is unseen, yet its force can manifest itself in various ways through various channels, and it is even possible to transfer it from one person to another if the medium is so constituted, as in hypnotism, thought transference, and similar phenomena. It may occur to you to ask why has the subject of insane movement and obsession been chosen for this paper; well, gentlemen, for some years it has been my lot to witness, on my daily round of the wards, grotesque movements, antics and pantomimic display by patients, which, were they not interesting as symptoms and physical signs of nervous disease, might otherwise be depressing because of their meaninglessness. About three years ago, however, I had my attention drawn to a woman who seemed engaged in making movements, the precise character of which I had not read of or seen before in any asylum. I shall show you this patient making these movements by means of the cinematograph. We would have brought her here only she obstinately refuses to operate when watched, and it was necessary to have the cinematograph pictures focussed through a partly open window when she least suspected observation. Gentlemen, we are well acquainted with such terms as insane acts, insane expression, insane language, insane conduct, and insane movements.