_Power of Suggestion._--In all these forms of delirium now described, whether artificial or natural, the mind is open to suggestions from without, and these become often controlling ideas. Hence it is of imperative necessity that the attendant should be on his guard as to what he says or does in the presence of the patient. An instance in point is related by Dr. Carpenter, in which a certain eminent physician lost a number of his patients in fever by their jumping from the window, a fact accounted for at once, when we come to hear that he was stupid enough to caution the attendants, _in the hearing of his patients_, against the possibility of such an event. II. _Permanent Forms._--I proceed next to notice those more permanent forms of mental disorder, commonly termed _insanity_, a term properly applied to designate those cases of abnormal mental activity in which there seems to be either some settled disorder of the intellect, as, _e. g._, when the brain has been weakened by successive attacks of mania, epilepsy, etc., or else some permanent tendency to disordered emotional excitement. _Disorder of the Intellect._--Where the intellectual faculties are disordered, the chief elementary feature of the case is the same as in those already noticed, viz., _Loss of voluntary control over the mental operations_--the psychological ground-work, as we have seen, of all the various forms of abnormal mental action which have as yet come under our notice. _Memory affected._--In the cases now under consideration, the memory is the faculty that in most cases gives the first signs of failure, particularly that form of memory which is strictly voluntary, viz., recollection. In consequence of this, past experience is placed out of reach, cannot be made available, and therefore reasoning and judgment are deficient. The thoughts lose their coherency and connection, as they are thus cut loose from the fixtures of the past, to which the laws of association no longer bind them; they come and go with a strange automatic sort of movement, over which the mind feels that it has little power. Gradually this little fades away; the will no longer exercises its former and rightful control over the mental activities; its sway is broken, its authority gone; the mind loses control of itself, and, like a vessel broken from her moorings, swings sadly and hopelessly away into the swift stream of settled insanity. The mind still retains its full measure of activity, perhaps greatly increased; but it acts as in a _dream_. All its conceptions are realities to it, and the actually real world, as it mingles with the dream and shapes it, is but vaguely and imperfectly apprehended through the confused media of the mind's own conceptions. All this may be, and often is, realized, where there is entire absence of all emotional excitement.