The normal mechanism of the cerebral cortex may be impaired in a variety of ways.
Pathology, MENTAL.—I. LOCALIZATION OF MENTAL FACULTIES.—In the cerebral cortex—that is, the thin covering which envelopes the entire surface of the brain—are distinguished various areas, connected by long nerve tracts with the organs of sense, the skin, the muscles, and in fact with the entire surface of the body. These connections constitute what is known as the Projection System. There are other areas which are not connected with the outer world, but are related in the closest manner by numerous nerve fibres one with another, and with the areas of the projection system. These constitute the Association System. In the former, definite elementary psycho-physiological functions are accurately localized. There are sharply defined centers for the movements of the individual members (the tongue etc.), for the sensations (taste etc.), for hearing, sight etc. In the left cerebral hemisphere (in the right for left-handed persons), there is a specifically human center, that for speech; destruction of this definite portion of the brain cortex causes a loss of the power of speech and of the understanding of spoken words, even though there be no deafness, paralysis of the tongue, mental disorder, or anything of this order. The higher and specifically psychical functions, and indeed all psychical processes (attention, mental moods, will, etc.) are localized in the association centers, the entire massive frontal lobes serving exclusively as such. Modern attempts to localize the individual mental faculties are as little successful as Gall's endeavors to deduce scientifically defects or developments from the formation of the skull. The external forms of normal psychical conduct have a normally functionating foundation—a healthy brain cortex; unhealthy changes in this latter disturb the normal psychical processes, that is, they lead to mental disease. II. CAUSES OF MENTAL DISTURBANCES.—The normal mechanism of the cerebral cortex may be impaired in a variety of ways. Impairment may result from the originally insufficient or defective construction of the entire brain (as in congenital dementia, idiocy), or by the destruction of extensive portions of the normally developed brain by injury, Inflammation, softening, malignant new growths etc. In very many cases it is due to the action of poisons, which either temporarily or permanently affect the activities of the sound and well-proportioned elements of the cortex. The number and variety of such active poisons is extremely great; among them are alcohol, morphine, cocaine, hashish, lead, poison products of microscopically small organisms or bacteria (fever deliria), abnormal products of metabolism coming from the gastro-intestinal tract (gastro-intestinal auto-intoxication—hallucinatory confused states), syphilis (in general paresis), poisons from the disturbance of important glandular organs (e.g. disease of the thyroid glands in the dementia of cretinism). In other cases, a disease process of the blood-vessel system affects also the blood vessels of the brain, and thus injures the cerebral cortex (mental diseases due to the calcification of the blood vessels, arterio-scelerotic psychosis). One and the same poisonous agent (e.g. alcohol) may be taken within definite limits and withstood by one individual, whereas another individual's reaction to the drug may occasion a nervous or mental disease. The personal predisposition plays an important causative factor. This individual constitution (i.e. inferiority, lower capacity for resistance) of the central nervous system is for the most part congenital and hereditary, just as temperament, talent etc. Mental diseases due to alcoholism or nervousness are doubly severe in persons to whom a corresponding taint has been transmitted by their ancestors. In some instances this inferiority may be induced in previously healthy and normally constituted nervous systems by sunstroke, concussion of the brain etc. Injuries to the head, especially those accompanied by concussion of the brain, cause not only an increased disposition to mental disease, but are not infrequently its direct cause. A chronic state of exhaustion produces psychoses, severe and protracted haemorrhages, weakness due to chronic purulent disease, malignant new growths, etc. Occasionally the mental disturbance bears a direct relation to phases of the female sexual life (menstruation, pregnancy, labor, suckling, change of life). In some markedly predisposed individuals, very intense bodily pain or continuous physical irritations may occasion attacks of mental disturbance (confused states in migraine, toothache, polypi in the ear, worms in the intestines etc.). In very many instances we are entirely ignorant of any direct cause, and can only interpret the unstable disposition as due to a strong hereditary taint. In many forms of mental disease we know absolutely nothing concerning the causes. It is striking that psychical factors themselves (worry, care, shock etc.) as sole and direct causes of mental disease play a very minor rôle—a fact in striking contrast to the popular notion. Only in extremely hysterical individuals, i.e. those already disposed to disease, do violent psychical emotions frequently give rise to rapidly-passing attacks of mental disorder. Furthermore, long-continued excitement, trouble, and the like, work only indirectly in the aetiology of the psychoses—e.g. by reducing the power of resistance of the central nervous system, that is, by giving rise to an increased disposition to nervous and mental disease, which itself is transmissible to posterity. Alcoholics make up a third, paretics almost two-thirds of all the mentally diseased. If the teachings of Christianity were to be generally followed, there would very rarely be a paretic, since for the most part syphilis is acquired only from illegitimate intercourse; there would be no alcoholism; and the untold distress caused by mental disturbance would be spared mankind. With reference to the question whether one may through one's own fault bring on psychoses [as was expressly taught by the Protestant psychiatrist Heinroth (d.1843)], modern psychiatry teaches as follows! as has been said above, there are many purely bodily causes of mental disease, in connection with which there can be no question raised as to personal responsibility. In the case of alcoholism the matter is not so simple. While it is certain that the abuse of alcohol is one of the most important causes of mental disease, it is also certain that a great proportion, even the majority, of habitual drinkers are severely burdened by heredity, and start as psychopathic inferiors. They are not degenerate because they drink, but they drink because they are degenerate, and alcoholism merely destroys an already ailing nervous system. The true cause of drunkenness lies primarily in the individual's constitution, and may frequently be traced to the ancestors. The sins of the fathers are visited upon the sons, even to the third and fourth generation. In so far as illegitimate intercourse is a sin, syphilis and its attendant paresis may be regarded as one's own fault. It should not, however, be forgotten that syphilis can be acquired in other ways (e.g. by drinking from an infected glass). One finds the accusations of conscience and self-reproach in wholly irresponsible melancholic patients, and unrepentant criminals often live a long life without developing insanity. In short, the question whether the soul through its passions or burdens can make itself diseased must in general, according to modern experience, be answered negatively, or the possibility of such causative combinations may be acknowledged only with important reservations and the greatest restrictions. III. VARIETIES OF INSANITY.—The forms that mental disease may assume, according to their symptoms, their course, and their results, are extraordinarily complex. Only those of most importance will be touched upon. (I) Melancholia.—The most important feature here is a primary (sc. not induced by external events), sad, and anxious depression, with retardation of the thought processes. The patients feel themselves deeply unhappy, are tired of life, and overwhelm themselves with self-reproaches that they are unable to work, are lazy, stupid, wicked, or unamiable. In many cases the patients themselves can give no reason for their depression; they often cite in explanation long-forgotten sins of youth, all kinds of more or less unimportant occurrences and circumstances, the cares of daily life which are treated as a matter of course in times of health, or the very symptoms of their illness. Because they take no pleasure in anything, in prayer or in the presence of their families, they accuse themselves of impiety and want of affection. In other instances pure delusions arise. The patients accuse themselves of crimes which they have never committed: they have made everybody unhappy, have desecrated the Host, and have given themselves up to the Devil. Many cases of daemonomania of the Middle Ages and of the times of the Reformation belong to this category, as was clearly recognized by many ecclesiastics. Regino, Abbot of Prüm (892-99), Gregory VII (1074) etc. protested energetically against the execution of witches; the Jesuit Friedrich von Spee (d. 1675), in his "Cautio criminalis", condemned the trying of witches as an institution opposed to humanity, science, and the Catholic Church. The patients often feel a terrible anxiety, fear a cruel martyrdom; sleep suffers, bodily nutrition fails, and painful centers of pressure are often found in different nerve tracts. The danger of suicide is extremely great. The greater number of all suicides occurs as a result of recognized melancholia; other conditions, such as an intense state of anxiety, may often render such patients dangerous also to others. The self-accusations are uninfluenced by any words of comfort; a hundred times confessed, they return again and again. The severest cases end in a condition of inability to speak or to move (stupor). (2) Mania.—By this we understand a primary (i.e. not caused by external influences), happy, elated mood subject to very rapid variations, especially to impulsive, wrathful emotions. Self-consciousness is increased, the flow of ideas is precipitate and rambling; there is over-talkativeness and excessive restlessness. The severest cases end in flighty ideas, confusion, and frenzy. But even the mild cases are disastrous for the patients and for their surroundings. Abnormal sensuality shows itself; individuals of previously high moral standards give themselves up to violent alcoholic excesses, and practice all kinds of sexual crimes. The patients are senselessly lavish, are guilty of deceits and thefts, and, by reason of their irritability, quarrel with their associates, superiors etc., insult them, and disturb the public peace, commit violence, are arrogant, quarrelsome, contentious, and delight in intolerable hair-splitting. Sleep is badly broken, the eyes shine, the play of the countenance is full of expression and vivacious; many patients resemble persons slightly intoxicated. Very frequently maniacal and melancholic states occur with characteristically regular alternations, and repeat themselves in one and the same individual, who during the intervals is mentally normal (circular insanity with lucid intervals). (3) General Paresis.—This disease leads with gradually increasing mental and physical decay to dementia, paralysis, and death. Frequently, in the early stages maniacal states, antecedent to severe dementia, are already observable. The patients are not only distracted and forgetful, but above all irritable, sleepless, brutal, shameless, sensual, lavish, extravagant etc., exactly like true maniacs, only in a still more coarse and unrestrained fashion, because of the simultaneously appearing dementia. Very often one finds the most grotesque and changeable ideas of grandeur (megalomania); the patients believe themselves immeasurably rich, are emperors, opera-singers, even God Himself; they have discovered perpetual motion, know all languages, have thousands of wives, etc. In other cases there are hypochondriacal delusions (the patients complain they are dead, or putrescent, etc.). Not infrequently the delusions are permanent, and the patients simply grow less rational from day to day. On the physical side, one observes most frequently a characteristic difficulty in speech; the speech becomes stuttering, uncertain, and finally an unintelligible babble. The pupils of the eyes lose their circular form, are often unequal (e.g. the right narrow, the left very wide), and do not contract on exposure to light (Argyll-Robertson pupil). Very frequently transitory apoplectic or epileptic attacks occur. In the last stages the patients are quite insane, prostrated, confined to bed, and pass their excretions involuntarily until death intervenes. In the earlier stages, almost at any stage in fact, marked and continued improvement and stationary periods may take place at any moment. (4) Juvenile Insanity (Dementia proecox).—This disease process usually sets in after the years of puberty, and gradually leads to a condition of dementia. Quite frequently only the ethical side of the psyche is at first affected. Boys and girls who have been active will suddenly develop a dislike to work, become irritable and headstrong, give themselves up to coarse excesses, go about in bad company, lose every family sense, etc. After a year or more the loss of intelligence becomes unmistakable. At times the initial stages take on a hypochondriacal coloring. Natures previously healthy and full of the joy of life begin to observe themselves with anxiety, go from physician to physician, have recourse to quacks, etc. They found their complaints on all kinds of foolish notions; there must be an animal, or a sore, in their stomachs, etc. Very frequently in the further course of the disease (occasionally at the beginning), hallucinations of hearing and of sight occur. Conditions of confusion, delusions of persecution, of poisoning, of megalomania of varying types occur. Peculiar so-called catatonic states of muscular tension develop, in which the patients remain expressionless and motionless in all sorts of positions. Set forms of speech, certain songs and motions are repeated in a stereo-typed manner. All of these states can change with great rapidity. Very often a remarkably sudden improvement sets in, leading one to expect a recovery. Little by little a state of incurable dementia becomes established. (5) Senile Dementia.—On a basis of a general breakdown due to old age, there develops increasing dementia, chiefly characterized by a disturbance of memory. In the mild cases the patients remember the occurrences, persons, and names from their early years, but cannot retain in their memory anything recent. In the severe cases the patients live entirely in the past, speak of their parents as still living, think themselves from twenty to thirty years old, do not know where they are, nor what is going on about them. As a result such patients are easily led, are suggestible; they do not know, for instance, what they have done in the morning, but declare, on being questioned, that they have been to school. Married women recall only the names of their parents and forget that they have had children. As a result of forgetting many words, their speech also is often very characteristic. Many nouns having escaped them, they help themselves out by frequent repetitions of stop-gap expressions, such as "what-d'ye-call-it", etc., or they use tiresome circumlocutions (e.g. instead of key, they say, "a thing that one opens things with"). The patients are irritable, hypochondriacal, suspicious, believe that their pockets have been picked, or that they have been poisoned. As in general paresis and dementia proecox, it is especially important to remember that marked loss of the moral sense may for some time precede the loss of intelligence. Sexual desire especially mounts up again in unhealthy fashion in these old people, and leads with special frequency to immoral attacks upon small children. Very frequently, in the early stages of senile dementia, there may be observed silly, intense ideas of jealousy, whose object is often the aged wife with whom the patient has lived for many decades in the happiest of wedlock. By reason of the disturbance of memory and the above mentioned suggestibility, these patients often fall victims to unprincipled scoundrels, who swindle them out of their entire fortunes, induce them to make foolish wills, etc. (6) Chronic Delusion (Paranoia).—Certain patients develop ever-increasing fixed delusions with clear consciousness and without any weakening of the intellect. The individual stages of this disorder may usually be distinguished. At first, these patients believe themselves to be under observation, to be pursued by enemies. Everything that is done has a deliberate reference to themselves; people slander them, spy upon them, or watch them. Hallucinations of hearing develop (e.g. mocking, abusive voices). The circle of their persecutors gradually enlarges; it is no longer a definite person (an enemy, a rival, a business competitor, etc.) who is the originator of this persecution and slander, but entire classes or bodies (Freemasons, Jesuits, political parties, the entire Civil Service, the members of the royal house-hold, etc.). As their grandiose ideas develop, the patients believe themselves the victims of widespread intrigues and persecutions, because others are envious of them, or because of their importance. The concrete content of the delusions varies greatly in different cases, but remains fixed in the same individual. One believes himself to be an important inventor; another, a reformer; a third, a legitimate successor to the throne; a fourth, the Messias. In addition to the hallucinations of hearing, different bodily hallucinations develop. The patients feel themselves electrified, penetrated with the röntgen rays, etc. In the initial stages the patients are very often well able to hide their delusional ideas in case of necessity, and to pretend that they no longer believe in them (dissimulation). By reason of the obstinacy of the ideas of persecution, and especially because of their clearness of thought in other respects, these patients may become very dangerous, attacking those about them with violence, taking their revenge by killing, or by well-planned murders of their supposed persecutors. In many cases the apparent sanity of these patients, and the fanaticism with which they promulgate their ideas, deceive an uncritical following, so that healthy but undiscriminating people share in their delusions (induced insanity). Many cases of so-called psychic epidemics, of perversely abstruse religious sects, belong to this category. In some cases the ideas of persecution are based on real or imaginary legal injustice suffered by the patient, who then believes that all advocates, judges, and administrative authorities are in league against him (Paranoia querulans, litigious paranoia). Traces of this are seen in the cases of obstinate litigants, who spend large amounts of money on lawyers to recover absurdly insignificant sums. When their complaints are dismissed everywhere, they commit a crime merely in order to come before a jury and be thus enabled to renew their old suit. (7) Alcoholic Mental Disease.—In addition to what has already been said of alcoholism, it may be added that in chronic drinkers there often arise characteristic, motiveless delusions of jealousy (alcoholic paranoia), which, by reason of the habitual brutality of the drinker, lead to continuous cruelty, and at times to assault and murder of the wife. Pathological intoxication is another important disease, which the symptoms of ordinary drunkenness do not appear, but which constitutes a true psychosis. This is usually of short duration; the patients are for the most part unusually violent, are entirely confused, and on recovery have no memory whatever of their mental disturbance. In delirium tremens, in addition to the marked tremor, sweating, and absolute sleeplessness, one finds vivid hallucinations of sight (of numberless small animals, mice, vermin, men, fiery devils, etc.), confusion, and feverish activity, during which the patients go about restlessly, working with imaginary tools. In other cases active hallucinations of hearing take place. They hear threatening and abusive voices, which may make the patient so anxious as to lead him to impulsive suicide. (8) Epileptic Psychosis.—Mild but permanent psychical anomalies are observed in very many epileptics. These patients are for the most part extremely sensitive and irritable, and, in contrast with this, may of ten simultaneously show an exaggeratedly tender and pathetic pietism. Not infrequently one observes characteristic periodic variations in the mood. From time to time the patients themselves feel an incomprehensible internal unrest, anxiety, or sadness; some seek to mitigate this condition by taking strong nerve poisons, at times in excessive doses (many cases of dipsomania belong to this class); others have recourse to debauchery; a third class go off like tramps for days; while a fourth attempt suicide. In other cases we meet with moodiness, which is not sad but irritable and angry, and consequently differs from the regular irritability of the epileptic; it frequently leads to most violent attacks upon those about them. Such conditions may often be traced even to earliest childhood. In connection with eclampsia, or even in its place, there often take place characteristic mental disturbances which begin very suddenly (dream or twilight states), last but a short time and pass, usually leaving no trace in the memory. These attacks show themselves outwardly in characteristic impulsive acts—as for instance in aimless wanderings (many cases of military desertion are due to such attacks), or in delirious confused conditions, mostly of a horrifying nature (fire, blood, ghosts, etc.). Such patients are often very dangerous, for in their blind anxiety they assail those about them, no matter who they may be. The cases among the Malays of "running amuck" are of this nature. In other cases of frequent occurrence the patients have visionary, ecstatic deliria; they sing psalms aloud, believe that they see the heavens open, see the Last Judgment, speak with God, etc. (Mohammed was an epileptic). Often the attacks occur only at night (epileptic night-walkers, somnambulists). (9) Hysterical Psychosis.—M any hysterical patients are at the same time permanently abnormal from the psychical point of view; they are egregiously selfish, irritable, and untruthful. Conscious simulation and diseased imagination run into one another so as to be indistinguishable. The mental disturbances of the hysterical show many superficial resemblances to those of the epileptic; the latter however are spontaneous, while the former are due to definite psychical causes, fright, anger, and the like; the sexual life also plays here an important role. Visionary ecstatic dreamy conditions occur, whereby an hysterical person can psychically infect hundreds of others (cf. the epidemics of the Middle Ages of flagellants, dancers, etc.; superstitious "miracles" of modern times; speakers of foreign tongues, and the like, where no sharp boundary exists between conscious swindling and pathological suggestibility). On the physical side one meets with strange paralyses, cramps, blindness, isolated anaesthetic spots [thus explaining the notorious "mark of the devil" in the "Malleus Maleficarum" (1489), met with in ancient witch trials]. All of these symptoms can disappear just as suddenly as they come. The majority of the wondercures by charms or similar superstitions are possible only in the case of hysterical persons, in whom the imagination causes both the disease and the cure. In modern times hysteria plays a large rôle in injuries—traumatic neurosis, "railway spine"—which is a combination of symptoms following a railway collision, or after accidents during employment. (10) Imbecility, Weakmindedness.—The severer forms (idiocy) and also those of moderate severity are easily recognized, even by the layman. The milder forms, however, may be overlooked very readily, since the mechanical accomplishments of memory may be very good, although the judgment (i.e. independent critical thought) is lacking. The weak-minded know only what they have committed to memory, but not the why and wherefore; they cannot draw conclusions, cannot adapt acquired knowledge to suit new and unaccustomed circumstances; they are at a loss when confronted by questions demanding intelligence. The weak-minded child, for instance, can learn a poem by heart, but cannot by himself perceive its significance; he can name the holidays, but does not understand their meaning; he can calculate well (i.e. mechanically) 9+3, but does not understand the question: "I think of a number, add 3 to it, and the answer is 12; what is the number I thought of?" By reason of their inability to think independently, such individuals are blindly led by the authority of others for good or evil. Because of the impossibility of reflecting upon anything exactly, they often commit, not only very foolish, but also dangerous and criminal acts, to free themselves from a momentarily unpleasant situation. Their emotional life is characterized by unreasonableness and irrepressibility. On the physical side one finds deformations of the skull, defects of speech, squint-eyes etc. One of the most important causes is alcoholic excess on the part of the parents; brain disease during childhood or before birth is also sometimes responsible. In many eases the defect involves that side of psychical life which is called the moral or social side, which cannot be acquired by intellectual means but is essentially connected with sentiment. Without moral sensibility, moral conduct is impossible. Hence arises the sad picture of the incorrigible reprobates who cannot be reached by educational influences, who in spite of kindness or sternness, in spite of the best example and breeding at home, are criminally inclined from childhood, and later become lazy vagabonds, prostitutes, or habitual criminals. These children, when hardly past infancy, are conspicuous for their unusual unruliness, selfishness, and lack of family affection. They show a characteristic malice and cruelty, maltreat animals in the most refined ways, and take a truly diabolical delight in tormenting their brothers, sisters, and comrades. They have a kind of explosive irritability and impulsive sensuousness, shown especially in an uncontrollable appetite for sweets, to satisfy which they have recourse even to theft and violence. They take to drinking when very young, and practice various other forms of immorality. Shamelessness, absolute laziness, and an extreme mendacity always characterize these persons. Their mendacity appears not only in lies told to escape punishment or to obtain something desirable, but also in fantastic romancing (pseudologia phantastica). We also usually observe in these patients a variety of bodily malformations and combinations of epilepsy and hysteria. As causes may be mentioned: heredity (especially from alcoholism), infantile brain disease (severe epilepsies), injury to the infantile skull during childbirth, cerebral concussion, etc. (11) Compulsory Ideas.—Even in patients whose intelligence is intact, certain ideas recur over and over again against their will, cannot be banished, and hinder and cross the normal flow of ideas, in spite of the fact that their folly and senselessness are always clearly recognized. The number of these impulsive ideas is very great. For the clergy the knowledge of certain forms is important, especially those that occur fairly frequently among religious persons, and are highly troublesome and painful. Such people, for instance, although they are believers, are forced constantly to brood over such questions as: "Who is God?" "Is there a God?" Others have fancies of the lowest and most obscene character, which annoy them only during prayer, and return with the greater persistency according as the patient is more anxious to dispel them. Such patients require hours to say a simple Pater noster, because they believe they have profaned the prayer by a sudden obscene fancy and must therefore begin all over again. The reassuring words of the confessor make little impression, save for the moment. Such sufferers torment themselves and their confessor incessantly by the endless repetition of their religious scruples, notwithstanding the fact that they clearly recognize the disordered compulsion (i.e. the involuntary nature of their ideas). But they cannot help themselves; the thoughts return against their will. (12) Menstrual Psychosis.—A few words may be added about a mental disturbance, which is of importance to jurists and to the clergy. In nervous women a menstrual psychosis occurs, i.e. mental anomalies which appear only at the time of the catamenia (usually a few days earlier) in individuals otherwise healthy. Conditions of confusion, unfounded ideas of jealousy, or excited states with marked excitability or sexual excitement manifest themselves. In women just delivered, excited and confused states occur in which the patient kills the newborn child; afterwards there is complete loss of memory of the deed. (13) Impulsive Psychosis.—By this is meant the occurrence of an irresistible impulse to steal (kleptomania), to burn (pyromania), to wander about (poriomania), the diseased nature of the action being especially recognizable in the complete lack of motive (no need, no satisfaction, etc.). The stolen articles, for instance, will not be used or sold, but carelessly and immediately thrown away after the theft has been committed; the thief often enjoys good social and material position. Such impulsive inclinations often exist throughout life, but oftener occur at intervals—as for instance during puberty; in women, not infrequently only during menstruation, or during pregnancy. In all these forms, as also in cases of so-called moral insanity, one must be unusually sceptical if one is to avoid favoring the introduction of the most dangerous abuses into the administration of justice. (14) Sexual Psychopathy. Anomalies of the Sexual Life.—The pathological abnormalities of the sexual impulse belong to the most melancholy chapters of psycho-pathology, and the horror that arises from the study of these occurrences can only be mitigated by the knowledge that what is so frequent is not always a disgusting vice and depravity, but often a mental disorder. But, as has been already said, we should be exceedingly cautious in assuming the existence of mental disturbance in cases which naturally lead to criminal prosecution, and where there is of course frequently a tendency to simulation. IV. FREEDOM OF THE WILL AND RESPONSIBILITY., In the question of moral responsibility or liability (from the theological or legal standpoint) a further and very important question arises. Mental soundness implies freedom of the will, while mental disease destroys it. In nature, however, there are no rigid, definite boundaries between disease and health, but only gradual transitions. We meet with so-called "borderland" cases between health and disease, a well-recognized example being weak mindedness. While the difference between the two extremes (an animal-like idiot, on the one hand, and, on the other, a Newton, a Pasteur, etc.) is at once palpable to all, where are the sharp boundaries between the moderately serious and mild forms of imbecility, between these latter and the very mildest forms, and finally between these and simple, but in no wise pathological, stupidity? The same may be said of moral imbecility, which passes by insensible gradations from the undoubtedly healthy to the irresponsible, superficial, sensual, and violent individual. The same may be said of menstrual psychosis, which shows its physiological roots in the increased general nervousness of every woman at the menstrual period. In short, in the entire domain of psycho-pathology one often meets with these borderland conditions, and the question of freedom of will cannot be answered by a simple yes or no, but requires a strictly individual weighing of all of the conditions of the concrete act. Not infrequently the psychopathic changes constitute, not indeed a total exculpation, but a mitigating circumstance. Or the matter may be such that one and the same individual, by reason of his mental abnormality, may be completely responsible for one crime, and irresponsible for another. A kleptomaniac, for instance, certainly commits a theft in a condition of irresponsibility; he must be held to answer, however, for another type of crime, for instance, an act of immorality. Even individuals, who are continuously free from characteristic psychopathic traits of a general nervous order, may by a combination of a number of definite external disturbances develop passing conditions of irresponsibility. The so-called pathological affects belong to this class. By reason of the simultaneous combination of long-continued depressing influences (trouble, care, etc.), of fatigue, sleeplessness, exhaustion, hunger, digestive disturbances, and pain, a normal emotional activity may reach a pathological or diseased height, accompanied by impulsive violence, and followed by dreamy or incomplete memory. V. PATHOLOGICAL CHANGES IN THE BRAIN STRUCTURE.—Constant and definite changes in the brain we know to be proved at the present time only in such forms of mental disease as accompany defective states, either of congenital (e.g. idiocy) or acquired origin (e.g. senility, paresis etc.). The weight of the brain remains considerably under normal in these conditions. In contrast to the average of 1360 grams for males, and 1230 grams for females (the weight of Gauss's brain was 1492 grams; of Turgenieff's, 2120 grams), in full-grown idiots we find weights of 417 to 720 grams (in one case only 200), and in paretics weights of about 1000 grams. With the naked eye one can see in paresis, in senile dementia etc., the great diminution and disappearance of the cerebral cortex, adhesions between the cortex and the brain coverings, oedema of the ventricles, scars, shrinkages, softenings, changes in the blood-vessels, etc. In idiots one observes in addition the most various congenital malformations (resemblance to lower animals, or persistence of embryonal stages, etc.), the remains of inflammatory processes, etc. The pathological findings by the microscope of fine changes in the brain cortex (in the ganglion cells, nerve fibres, etc.) are even richer. In all the other forms of mental disease pathological anatomy has failed to give us any information. Autopsy either reveals no abnormal conditions in the brain, or the changes that are found are either inconstant or have no particular relation to the psychosis, as for example the very fine alterations of the cortical cells, which modern microscopy has proved to exist in acute psychosis, can be induced also by other bodily diseases which cause death. Our knowledge in this field is still very hazy.