On the other hand, when illusions occur in the insane, they are unable to correct them in consequence of a derangement affecting the psychical centres of the brain.

İllusions of sight, hearing, and general sensation are frequently present in delusional insanity, melancholia, and general paresis. Wrong, imperfect, or exaggerated interpretations are given to experiences which have but a slight foundation in fact, and give rise to delusions. The ticking of the clock on the mantel becomes converted into the voice of one speaking, to whom replies become necessary; the pain incident to an ulcerated stomach becomes the evidence of the presence there of a snake which has been. swallowed on some former occasion.

Illusions of the different senses are also often present in the acute forms of alcoholić insanity, and in forms of disease other than insanity. They are generally of much less importance than hallucinations.

LECTURE III.

IMPERATIVE CONCEPTS-INSISTENT IDEAS.

CONTENTS:-Concepts-Definition of—Etiology-Mode of Origin—Forms of Disease-Progress and Course-Illustrations-Character of ConceptsSignificance of Insistent Ideas-Formation and Progress-Characteristics-A Case of Long Standing-The Emotion of Fear-Fear of Places— Of Contamination-Of Improper Conduct, etc.-The Subjects about which they Revolve very Numerous-A Case-Characteristics as Described by Krafft- Ebing-Treatment.

Concepts, as used in the following pages, may be regarded as the simplest forms of mental action, after those of sensation and perception. They are isolated thoughts relating to things or subjects. They are limited, and constitute the elements of thought processes which enter into judging, reasoning, and the formation of designs, purposes, etc. They become imperative when they occupy the mind for the time being and dominate its course of action.

Etiology.-Imperative concepts arise from the operation of irritations, either centric or reflex, acting upon brain centres of thought which are in an abnormal physiological

* This is a more limited signification of the term concept than is in common use, where it is made equivalent to the term notion, which embraces not only the first impression of any subject or thing, but also the qualities or characteristics which pertain to it. I have, however, ventured to use the word concept rather in its etymological sense, as signifying the initiatory element of the thought process pertaining to any subject, rather than a completed notion. I know of no other term which, from its derivation, so accurately indicates the form of mental activity of which I desire to speak.

condition. The predisposing cause in some cases may be an anæmic state of the brain, and in others a neurasthenic condition or one of irritable weakness, affecting unequally the different psychical centres, whose combined and normal action is essential to healthy mentality. Heredity is also an important factor, especially when it entails a general paranoiac condition of brain. It is, however, found in experience that these concepts arise in many cases in which, apparently, neither of the above factors exist. They may arise from any cause which serves largely to increase or diminish the normal amount of the nervous energy of the system, such as shocks, profound grief, etc., and thus induce mental derangement.

Mode of Origin.-The mode of their origin appears to be similar, if not identical, with that of hallucinations, except that in the imperative concept the impression or the irritation which gave rise to it is not projected, as in the case of hallucinations, toward the sensorial centres, but rather toward the psychical and motor centres, causing intense, peculiar, or irrational manifestations of manner or conduct.

The character of concepts in relation to their physical basis depends, in the first instance, upon inheritance and educational influence; but beyond these factors they will depend upon the condition of the nerve-cells which constitute the psychical centres. This, again, will be influenced by the character of the blood supply and the evolution of nerve energy. In case the cells have been over-taxed during considerable periods, or have inherited a predisposition to instability, they become unable to recuperate and restore this expended energy during the usual periods of rest and sleep at night, and, in consequence, pass into a state of morbid weakness, irritability, and sensitiveness;

they no longer respond in a normal manner to such stimulations and impressions as are received upon them. They become easily excited, and the concept to which the stimulation has given rise is no longer under the full control of the inhibitory centres; it may be, and often is, projected into expression, even in spite of the will of the subject.

Again, the morbid character of concepts may appear in their exaggerated nature and their tendency to usurp the field of consciousness to the exclusion of others, in consequence of local congestions and an unequal distribution of nerve energy throughout the different centres of the cortex. In the healthy condition of the brain, concepts arise in some order or system; i. e., they have an intimate connection with such subjects as the individual is engaged upon or has been thinking about and is directly interested in. Indeed, the more absorbing the interest, the more surely do concepts arise in direct relation to it. But in a weak or anæmic state of the brain the concept may arise suddenly without such connection and become imperative in its action; the inhibitory centres being in a partially inactive or dormant state, the movement becomes largely automatic. Imperative concepts more often pertain to matters or subjects which have little or no relation to the recent mental experiences of the individual, unless in some remote degree, and they may arise from the excitation of memories relating to experiences long passed.

Forms of Disease.-Imperative concepts are present more frequently in primary delusional insanity and melancholia, and are the initial element in the formation of insistent ideas and morbid impulses. The degree of pertinacity or persistency with which they continue to absorb and dominate the mental activities will depend upon the

extent and character of the disorder of the brain, and, to some extent, upon the length of time during which it may have existed. They also tend to become more pronounced and dominant when they arise from the primordial character of the nerve elements which has been impressed upon the cortex by inheritance and the disorders and accidents incident to infancy and early childhood.

Progress and Course.-It should be observed that these profound mental impressions may exist at times in the sane as well as in the insane brain, but in the normal condition of the brain they exercise only a limited influence. They may incite to acts and speech, but their influence is always modified by other mental concepts which are projected into the sphere of consciousness, and are under the control of the ego. With the insane their influence is so potent as to overshadow other concepts, usurp their sphere of activity, and lead to the formation of new ones, or even combinations of them. They wholly dominate the course of activities for the time being and influence the unhappy subject toward conduct of the most singular, absurd, or outrageous character. A female patient was brought to the Retreat, a few years since, who remained in a condition of apparent reverie during several days, and said very little, except in reply to questions. While in her room, one morning, she suddenly thrust her hands through several panes of glass, which caused a considerable hemorrhage, and the blood covered her hands, face, and portions of her dress. She afterward said that the impulse to put her hands through the glass arose suddenly in her mind in consequence of the constant recurrence of that passage, “Ye have not yet resisted unto blood," and she adopted this means to do so.

As new areas or paths of activity in the nerve-cells become implicated in the morbid process, these imperative