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some desired result and a feeling of pleasure or satisfaction tends to be repeated, so a movement or act which has produced an undesirable result or unpleasant feeling is not likely to be voluntarily repeated, for whenever an impression whose response would be unpleasant comes into consciousness, the impulse is repressed or inhibited, so that the reaction does not take place. Laboratory experiments have shown that purely reflex responses can be inhibited by an intercepting impulse, and it is a fact of experience proved almost every moment of every day that whenever an impression comes into consciousness its direction is determined and the immediate response may be checked or inhibited by conflicting impressions. Inhibited impressions survive in memory long after the event has taken place and at a later time may become active to influence behavior. Inhibition implies the exercise of judgment, a capacity which is developed through experience. Innumerable tendencies to react to inherent impulses and sense impressions are continually coming into consciousness, only a small part of which are allowed to find expression in action, for the remainder are repressed and the energy of the impulses tends to become dissipated within the nervous system. Psychiatrists hold the belief that various impulses so repressed remain active and under certain conditions become potent in the causation of some of the functional mental disorders.

In some types of mental disease the power of inhibition is so interfered with or weakened by the action of intercepting impulses that the mind is no longer able to exercise direct control over the activity, for the patient seems to react to every impression and the mental and muscular activity are markedly increased; or, the power of inhibition may be so strengthened by other impressions that very few impulses are released to find expression and the activity is greatly diminished, but when these conflicting ideas and impulses are removed other ideas and impulses are liberated and become active.

Instincts. There are many inborn tendencies to act which have neither been acquired by experience nor learned by training, and whose expression is not directly under the control of the will. These tendencies are termed instincts. The responses are for the most part made up of simple reflex acts which must be thought of as depending upon pathways and connections already made by nature. These tendencies are common to all the species and are transmitted from generation to generation, and serve a useful purpose in the mental and physical development and the adaptation of the individual to his environment. The primal instincts have to do with self-existence and the sucking instinct is about the first to appear, as also are the tendencies to grasp and carry objects to the mouth. Other basic and fundamental instincts are concerned with self-protection and preservation, and are shown by the tendencies to repulse and flee from danger, to resent, resist and fight when necessary, and those which have to do with the perpetuation of the species, the sex and parental instincts. In man whose infancy and period of dependence is prolonged so much beyond all other species, these instincts appear very gradually, and while some tendencies may appear soon after birth and in the early days and weeks of life, others, like creeping, walking, talking, etc., are delayed for several months; others, like self-assertiveness and independence, appear with the development of personality, the consciousness of self; and others, like the sex and parental instincts, are further delayed and appear at the age of puberty and adolescence.

Some of the more common instincts are: Imitation, whereby one learns many of the more complex movements and acquires the behavior of those about him; play; rhythm; curiosity, finding out by questions and manipulations why things are thus and so and what they mean, how they are made and for what use; sociability or gregariousness, the tendency to be with others in a group; rivalry, striving to reach or attain the same objects and ends which others of the group are pursuing, and if possible to excel; coöperation,

the tendency to work with and be of help to others; collecting, hoarding and ownership; religious tendencies and the benevolent interest in the weak or suffering. All instinctive tendencies are not desirable, and throughout the ages those which have been useful have survived and by encouragement and expression have been developed, while those which served no useful purpose have been weakened by lack of exercise and encouragement or repressed and kept in subjection by fear of punishment or disapproval. Some of the combative instincts, which were very useful to primitive man when there were no agencies to protect his property or laws to regulate behavior, have little place in a community where civic laws and agencies have replaced individual brute force. Bullying, teasing tendencies often come strongly into prominence in early youth and are promptly weakened by criticism, disapproval and punishment, and tend to disappear. Tendencies to rob and to destroy, the predatory instincts, which may have been needful to primeval man, but through centuries of civilization have been suppressed, will sometimes spring up with tremendous force and energy. This is especially to be noted when boys in gangs will, on occasions when police vigilance is relaxed or wanting, destroy fences, mutilate houses, steal detachable property for no other reason than to find an outlet for imperious impulses, knowing full well the consequences if they are discovered or apprehended.

Throughout life these instinctive tendencies are operative and are ever seeking expression. In mental illness, when the power of inhibition is weakened, many of the primitive impulses which have long been repressed become active and find expression. Instead of trying to control them by direct inhibition or repression, it is far better to utilize the nervous energy in developing a new and more healthful form of activity; that is, control one activity which is not useful or desirable by doing something else which at least is not harmful, and if possible useful. In the reeducative measures which form so large a part of the nursing care of

the mentally ill the instinctive tendencies should be appealed to and utilized in the formation of new habits of thinking and acting, for efforts thus directed most frequently produce the desired results.

Habit formation. In physiology it is assumed that every impulse which discharges over a given route in the nervous system tends to make a pathway over which subsequent impulses, initiated by a like stimulus, will more easily travel, and that each repetition tends to make the pathway more deep and lasting. The ability to acquire various movements of skill solely by practice is the proof of this theory. An instinctive or voluntary act whose performance in the beginning was difficult and required constant direction by the mind is, after many repetitions, converted into an act which is performed easily and without conscious direction. The child learns to walk only by giving to every movement the most deliberate conscious attention, but in time and with practice the complicated muscular movements are made involuntarily, and the attention can be completely occupied with other interests, and only the initiation is conscious and voluntary. The response to the stimulus has become automatic or habitual, and whenever a given situation arises or impression recurs, the reaction will be what it has been in the past, unless it is intercepted or repressed, for the impulse will follow the old pathways of discharge. Behavior is very largely made up of these automatic responses or habits. Psychologists have estimated that not more than one in ten of our waking acts is the result of conscious choice or volition. Habits play a very important part in the development of the individual life, for they tend to make movements more simple, easy and accurate, to reduce fatigue and lessen the conscious attention required in their performance.

What is true of the reactions which are expressed in muscular movements is also true of mental reactions. An idea or feeling which has been associated repeatedly with another idea or feeling tends always to follow that pathway, for

habits of thought are just as easily acquired and firmly established as those expressed in muscular movements. The formation of good and healthful habits, both of mind and conduct, is of inestimable value in the preservation and promotion of health. When it is realized that every thought, every feeling, every action is being impressed and recorded in the mind to contribute in the future to determine behavior, too much attention and thought cannot be given to the formation of habits which will be useful, helpful and healthful. Character means, literally, to "engrave." The habits of thought and conduct which may be so largely determined and controlled by choice or volition are unconsciously being engraved on the mind and are subtly operating to mold the character. Professor James says: "The hell to be endured hereafter, of which theology tells, is no worse than the hell we make for ourselves in this world by habitually fashioning our characters in the wrong way. Could the young but realize how soon they will become mere walking bundles of habits, they would give more heed to their conduct while in the plastic state. We are spinning our own fates, good or evil, and never to be undone. Every smallest stroke of virtue or of vice leaves its never so little scar. The drunken Rip Van Winkle, in Jefferson's play, excuses himself for every fresh dereliction by saying, 'I won't count this time!' Well! he may not count it, and a kind Heaven may not count it; but it is being counted none the less. Down among his nerve cells and fibres the molecules are counting it, registering and storing it up to be used against him when the next temptation comes. Nothing we ever do is, in strict scientific literalness, wiped out."

Some functional disorders of the mind are kept going because certain pathways along which morbid ideas, doubts and fears tend to pass are so firmly established, and on account of the inertia of the nervous system old connections and associations are not interrupted but allowed to persist and continue and no new pathways are made. An important part of the nurse's duty is to help the patient to interrupt,