/ MENTAL PHYSIOLOGY MENTAL PHYSIOLOGY ESPECIALLY IN ITS RELATIONS TO MENTAL DISORDERS THEO. B. ^^YSLOP, M.D. LECTURER OX MEXTAL DISEASES TO ST. MARY's HOSPITAL MEDICAL SCHOOL. ASSISTANT PHYSICIAN TO BETHLEM EOYAL HOSPITAL, FORMERLY ASSISTANT MEDICAL OFFICER, ROYAL ALBERT ASYLUM FOR IDIOTS AND IMBECILES, LANCASTER, DEPUTY-PATHOLOGIST AND ASSISTANT MEDICAL OFFICER, WEST RIDING ASYLUM, WAKEFIELD Non eiiim tarn auctoritatis in disputando, quam rationis momenta qua?ienda sunt Cicero LONDON J. & A. C H U E C H I L L 11, NEW BURLINGTON STREET 1895 <.^ HW-w TO GEORGE H. SAVAGE, Esq., M.D., F.R.C.P., IN GRATEFUL ACKNOWLEDGMENT OF MANY ACTS OF KINDNESS AND ENCOURAGEMENT, AND AS A MARK OF APPRECIATION OF HIS TEACHINGS AND WIDENESS OF VIEW, THIS BOOK BY HIS FRIEND AND PUPIL, THE AUTHOR. P 11 E F A C E. In the following pages an attempt is made to bring together some of the more prominent phenomena of the brain and of the mind, both in their normal and morbid aspects. To the metaphysical and philosophical bearings of the various assump- tions involved in such an attempt, little or no prominence is given. In philosophy we are free to choose between a natural dualism and a hypothetical realism, or we may be materialists or idealists : in empirical psychology or physiology it would, presumably, be a work of supererogation to enter at length upon questions of epistemology or metaphysics. In discussing the relations of the outer world as the mind knows it, the assumption that complex mental experience is only an inner representative of a genuine externality has been adhered to, without entering into any philosophical account of the method whereby the existence of the whole outer world is inferred through its representative images. In dealing with many hypotheses which have been given to account for mental events in physical terms, objection has been taken throughout ; and little or no attempt has been made to speculate as to the ultimate nature or quality of nervous or mental events. In an elementary work of this description it is obvious, that an exhaustive account of the anatomy, physiology, and viii PREFACE. pathology of the brain would defeat its own object — viz.. conciseness. The author has, therefore, merely sought to bring into apposition, as it were, some of the more important cerebral and mental facts, and no pretence has been made to furnish the student with an elaborate treatise upon any department of the subject-matter. In the preparation of the work the aiithor has much pleasure in acknowledging, with thanks, the valuable assist- ance and advice of his friend, Mr. W. A. Haigh. His thanks are also due to his friends, Mr. H. F. Harding, for revisal of the proof-sheets, and Dr. ]\Iaurice Craig, for the preparation of the index. T. B. H. Bethlem Royal IIospital, S.E August, 1895. CONTENTS. INTRODUCTION. I The value of Hypotheses — Boundavies ot our Subject — Psyeholos^y as a Science — The Relation of Psycho-physiology to the General Study of Mind — Mind Relative or Absolute ? — Defini- tion of Mental Physiology — Mental Pathology — Physiological Pyschology — Relations of Mind to Body — Empirical Psycho- logy — Speculative Psychology — Spiritual Theories — Occa- sionalists — Pre-established Harmony — Theory of Animists — Associationists — Dualism — Monism — Automatism — Material Monadism CHAPTER I. AxATOJiY OF Cortex: Arrangement of Cortical Structures — The Nerve-Cell — Processes of Nerve-Cells — Nerve-Fibres — The Relation between Cells — The Neuroglia, or Connective Tissue Basis — Cell Elements — Caudate Fibre-Cells — Stellate Fibre-Cells — Protoplasmic Glia Cells — Physiology of Nerve- Cell : Nutritive Function — Transmission of Nerve Impulses — Excitability and Conductivity — The Functions of Nerves — Negative Variation ......... 24 CHAPTER II. Chemical Properties of Nerve-scbstance: Specific Gravity — Percentage of Water — Albumin — Potash Albumin — Nuclein — Neuro-Keratin — Cholesterin — Cerebrin (Ilomocerebrin Encej)halin) Lecithin — Protagon — Vascular Supply of the CONTENTS. I Brain: Basal Arterial System — Anterior Cerebral Arteries — Middle Cerebral Arteries — Posterior Cerebral Arteries — Arterioles of Cortex — Lymphatic System of the Beain : Eegulation of Cerebral Pressure — Lymph-Cisterns — Peri- vascular Channels — Cerebro-Spinal Fluid — Pacchionian Granulations — Subarachnoid Space — Venous Circulation — Quantitative Relations between Blood and Cerebro-Spinal Fluid — Brain-Mo\'ements : Pulsatile — Respiratory — Vas- cular — Nutrition of Nerve-elements — Functional Ilyperremias — Vaso-motor Centres — Influence of the Sympathetic . CHAPTER IIL Scheme of the Central Nervous System — Sensory Paths — Cere- bral Localisation for Touch — Course of Sensory Fibres — Special Senses : Sight, Ilearing, Smell, Taste — Motor Nerves : Cerebral Localisation — Projection Systems : Association Fibres, Fibrse Proprise — Value of our Knowledge of Cere- bral Localisation : Phrenology, Experimental Research, Com- parative Anatomy, Morbid Anatomy — Sensori-Motor Areas and their Relations to Mental Faculties : Views of Hitzig, Ferrier, Munk, Waller, etc. — Conclusions .... CHAPTER IV. Localisation of the Mental Factlties {continued): Sensory and Motor Areas subserve Mental Events — Localisation — Diffuse Localisation — Indifferentism — The Frontal Lobe — Intelligence not limited to Local Areas- Ratiocinative Theories: Neural Inference Scheme of Iluglilings-Jackson ; Meynert's View of the Forebrain ; Waller's A'icw, based upon Psychological Inference — Value of the Logical Mode of symbolising Neural Inference — Praefrontal Lobes: Experi- mental Researches ; Pathological Evidences — Consciousness pertaining to Lower Centres— Local Memories — Subjectivity of the Mind — Objective Contents of Consciuu.sness — Specific Functions of Nerve-Cells — Wallerian Scheme of the Four R's — Specific (Quantifications of Motion — Negative Value of Physical FormuUe — The ] )octrine of " Invariable Con- comitance'' 123 CONTENTS. CHAPTER V. PAGE Mind : Scope and Methods of Study — Total Resources at our com- mand for the Study of Mind — Subjective Methods — Subject- Consciousness and Object-Consciousness — The Objective 3Iethod — Logical Methods — Inductive Method — Deductive Method — Evolution Theories — Biological — Psychological — Presentationism — Mind-Stuff Theories — Atomistic Ilylozoism — Parallelism — Psychological Import of the Theory of Self- Compounding of Mental Facts — Unconscious Cerebration — Arguments for and against the Theory 149 CHAPTER VI. Sensation : Analysis of Sensations and Sense Percepts — Relation of Sensations to Perception — Molar Motions — Atomic and Molecular Motions — Motions of Ether — The Theory of Elec- tricity — Latent Chemical Energy — Power of Selection pos- sessed by Sense Organs— Characters of Sensation — Intensity or Degree — Liminal Intensity — Forms of Excitation — Weber's Law — Discriminative Sensibility — Maximum Intensity — Fechner's Psycho-Physical Interpretation of A^'eber's Law — Wundt's Psychological Interpretation — The Physiological Interpretation — Validity of Weber's Law — The Estimation of Magnitudes by Comparison — Measurement of Absolute Mental Magnitudes Impossible — Quality of Sensations — Generic and Specific Quality — Duration — Local Characters of Sensations — Taste — Smell — Touch — Specific Functions of Tactile Corpuscles or End Piulbs — Pressure Spots — Tempera- ture Sense — Common Sensation — Peripheral Reference of Sensations — Muscular Sense — Hearing — Sight — Pressure Phosphenes — Quality of Sensations of Sight — Simple and Mixed Colours — Colour-Blindness — Young - Helmholtz — Hering — Wundt — Von Kries — Franklin . ... 170 CHAPTER VII. Percepiion : External and Internal Perception — Apperception — Physiological Conditions of Perception — Space Form — Nati- vistic and Empiristic Theories of Percej)tion — Perception of Spatial Order — Theory of Local Signs — Eccentric Projection of Sensations — Sj^atial Discrimination— Special Channels of xii CONTEXTS. PAGI- Perception : Perceptions of Smell and Taste : Hearing : Touch : Muscular Sensation : Sight (Retinal, Monocular, Binocular) 20") CHAPTEE VIII. Sensory Perveusioxs : The f )rigin and Development of Sensory Perversions — Abnormal Conditions of Perception — Definition of Illusion — Sources of Illusion — Classification — Passive Illu- sions — Exoncural — Esoneural— Active Illusions — Voluntary — Involuntary — Secondary Sensations — Sound Photisms — Light Phonisms — Taste Photisms— Odour Photisms — Pain Photisms — Chromatisras — Gustatisms — Olfactisms — Laws concerning Secondary Sensations CHAPTER IX. Halllcixations : Distinction between Illusion and Hallucination — The Transition from Illusion to Hallucination — Relation of Imagination to Hallucination — The X^eui'al Process in Hal- lucinations — The " Bucket Theory '" — Anatomical Regions for Hallucinations and Sensations — Varieties of Hallucina- tions— Classification.s — Climc.vl Considerations : Statistics of 1,000 Cases — Perversions of Taste — Hypergeusia — Hypo- geusia — Ageusia — Parageusia — Perversions of Smell — Ilyper- osmia — Ilyposmia — Anosmia — Parosmia — Perversions of Siglit — Entoptical Cau.ses — After Images — Perversions of Hearing — Hyperakusis — Ilypakusis — Akusis — Parakusis — Perversions of Tactual Perception— Ilypersesthesia— Anaes- thesia — Pselaphesia — Algia — Perver.sions of the Muscular Sense — Kintesthesia — Illusions and Hallucinations in Dreams — Hypnagogic Illusions— Dreams in tlic Insane CHAPTER X. Mental Processes. Atte.ntion: Definition — P.sycho-Physical Process of Attention — P.sychical Theory of Attention — Th^ Xeural Processes in Attention — Monoideism — Polyideism — Reflex Attention— A'dluntary Attention —Adjustment of Attention— Attention and Genius— Morbid Conditions — Hyper-attention — Inatten- tion— lu Mental Disorders— Conception : Definition — Concept CONTENTS. xiii PAGE —Psychological View — Psycho-Pliysical Theories of Concep- tion — Physiological Theories — Association — Double Nature of Brain— Consciousness tlie Accompaniment of Nerve Action — The Theories of Discharge and Piesistance — Judgment : Definition — Degree of Perfection of Judgments — False Induc- tions — False Deduction — The Percei3tion of Ptcality — P>elief — The Insanity of Doubt — Imagination : Definition — Differ- ences between After-Images and Imagination-Images — The Neural Process of Imagination — Morbid Conditions — Simple Delusional States — Sensory Tyj)es — Emotional or Affective Types — Clinical Considerations ...... 291 CHAPTER XL Memor)>: Elementary Memory — Memory Proper — Secondary Memory — Relation of Memory to Belief — The Process of Recollection — First Impressions — Suggestion — Contiguity, Similarity, and Contrast — Associative Force — Complex, Convergent, Divergent, Obstructive — Methods of Cultivating Memory — Psycho- Physical Theory of Memory — Latent Mental Images — Relation of Primary Image to Eevived Image — Disorders of Memory: Forgetfulness — Amnesic States — Congenital Defects — Temjjorary Loss — Periodic Amnesia in Hypnotic States — Progressive Amnesia — Partial Amnesia — Agraphia, Aphasia, Aphemia, etc.— Hypermnesic States — Congenital — Temporary — Periodic — Partial — Paramnesic States — Simple States— By Association or Suggestion — By Identification 332 CHAPTER XII. Feelings : States of Feeling— Relation of Feeling to Knowing — Instincts and Emotions — Theory of the Emotions — Tempera- ments—Laws of Pleasure and Pain— Tone of Feeling — Physiological Theory of the Feelings — Feeling of Effort — Varieties of Feelings — Classifications — Disorders of the Feelings and Emotions : Sense Feelings — Feelings con- nected with Ideas — Intellectual Feelings — Rational Feelings — Disorders of Childhood, Puberty, Adolescence xiv CONTENTS. CHAPTER XIII. PAGE The Wim, : Definition— Deliberation — Choice — Resolution — Self- determination — Delayed Reflex — Influence of Habit — Desire — Psycho-Physical Processes of Volition — Volition not to be explained Anatomically, Physiologically^ Developmentally, or Pathologically — Reflex Acts — Periphero-Motor — Centro- Motor — Automatic Acts — Voluntary Acts — Motor Images — The Will Power in Hypnosis — The Feeling of Effort — Intro- spective Evidences — Physiological Inhibition — Nervous Resistance — Movements — Central — Peripheral — Simulta- neous — Sequential — Speech Movements — Disorders of the Kinsesthetic Word Apparatus — Deaf Mutism — Acquired Defects of Speech — Alliteration — Verbigeration— Akata- phasia — Speech Defects in the Insane — In Sleep and its Associated Conditions — Conduct — Nervous Mechanism of Conduct — Conclusions as to the Existence of a Will — Impairment of Will Power — Irresolution —Defective Impul- sion — Excess of Impulsion— Defective Voluntary Attention — Absence of Will— Conclusions 409 CHAPTER XIV. The Factors of the Insanities : Gro-wth and Development of the Mental Faculties — Developmental Processes in the Infant — Microkinesis — Micropsychosis — Reversion in Adults — Factors of Development. Internal Factors .- — Original Capa- cities — Genius — Degeneration and Genius — Balance as the test of Mental Health— Genius a Sociological not a Psycho- logical Concept — Hallucinations not Incompatible with Sanity — Mental Health not to be Estimated Entirely from an objective Standpoint— The Degenerate Advocates — Unre- liability of Statistics — Inlierited Dispositions — The A^iews of Spencer and Weismann — Hereditary Factors in Insanity — Consanguinity — Phthisis, Scrofula, Gout, Rheumatism, Syphilis — Alcohol — Diabetes — Neurotic Manifestations. External Factors : — Social I'lnvironments — Psychopathic Epidemics — Children's Pilgrimages— Lycanthropy — Rapha- nia— Sensory Types— Religious Impostures— Sympathy and Mimicry — Endemic and Epidemic Psycopathies — Folie a deiLC — Religion — Physical Environment — Seasons— Climate —Occupation — Town and Country Life 4.'3,'; CONTENTS. XV CHAPTER XV. PAGE The Factoes of the Insanities {coyitmued) : Physiological Periods of Life — Infancy — Causes of Idiocy and Imbecility — Types of Infantile Mental Defect — Night-Terrors — Dreams — Night- mares — Somnambulism — Infantile Insanity — Causes — Heat — Fevers — Masturbation — Puberty — Adolescence — Puer- perium — Menopause — Senescence — Bodily Affections as Factors — Genital — Urinary — Digestive — Circulatory — Re- spiratory — Factors — Other Diseases — Neuroses- — Spinal — Sympathetic — Cerebral — • Intoxicants — Immediate Factors — Vaso-Motor — Vascular — Nutritional — Hughlings-Jackson's Scheme of Factors — Conclusions 493 Appendix A — Hypnotism .......'.. 529 Appendix B — Psycho-Physics ........ 535 MENTAL PHYSIOLOGY. INTEODUCTIOK The Value of Hypotheses — Boundaries of our Subject — Psychology as a Science — The Relation of Psycho-physiology to the General Study of Mind — Mind Piclative or Absolute 'r — Definition of Mental Phy- siology, Mental Pathology, Physiological Psj^hology— Relations of Mind to Body — Empirical Psychology — Speculative Psychology — Spiritual Theories— Occasionalists — Theory of Pre-established Harmony — Animists — Associationists — Dualism — Monism — Automatism -Material Monadism, In a system of philosophy every affirmation is liable to have its truth deteniiined by a variety of tests. These tests must uot only be in accordance with our manifold conditions of knowledge, but they must also be proportionateh' varied. The student would do well to proceed according to the admir- able advice of Goethe : — "Let the incjuirer consider himself as one summoned to sit on a jnry. His part is mereh' to see \\.o\\ far the indictment is borne out \)j the evidence." Truth and distinctness of object are of primarj^ importance. The multi- tude of facts at our disposal must be carefull^^ sifted. We must discriminate between the essential and the accessor)', the important and the insignificant, and \\\\e\\ all the arguments in our scientific investigation are exhausted, we must not. by the construction of hypothetical fables, falsify many exist- ing truths by fictions of the imagination. In the domain of psychologv some inquirers search for novelty rather than truth, " 1 2 INTEODUCTION. and, A\'ith the pretence of solving doiibts, entertain us with hypotheses which are not only fanciful but absurd.* It is incumbent npon us, therefore, as a duty which we owe to science, to be most scrupulous and cautious in stating our individual opinions. Rather let us remain in a condition of uncertainty than propound doctrines which not only falsify existing truths, but even block the way to further research. If we look at the boundaries of our subject, on the one side we have the domains of metaphysics and ethics, ^\'hilst on the other, that of the human organism as viewed b^^ the physiolo- gist. We must endeavour to confine ourselves more particu- larly to our own portion of the study of philosophy, and with regard to the special requirements of the physician, abstract from the study of a rational or empirical psychology, only so much as is essential to our purpose. In specnlative psi/chology little or no account is taken of the relations of the mind and body ; the mind is regarded as a conscious being that perceives, thinks, imagines, remembers, feels, and wills ; and in regard to the infinite variety of relations that exists between the mind and the varied functions of the brain, no attempt is made to reduce them under general laws of cause and effect. I^he attempt to reduce them tinder such la\AS brings us to an empirical psychology, or method of thought resembling the natural sciences, and of which psychology and physiology form, of course, the component parts. The position of our own particular sciences would be as follows : — (1) Physiology. (a) Descriptive. (/>) Experimental, (c) Speculative. (2) Psychology. (a) Descriptive. (h) Experimental. (c) Speculative. * Those hypotlieses ■vvliicli luakc the results of pliysiology involve sub- jective data, and tliereby raise metapliysical questions as to the substantive or dynamic nature of mind, must be carefully distinguished from what we can with fairness acce])t as i)0stulates i)ertaining to the departments of physiology and psychology'. PSYCHO-PIIYSIOLOGY AXD STUDY OF MIND. o The relation of physiological psj^chology to the general study of mind is shown in the following diagram In' Baldwin* : — Psychology Empirical (Inductive) Rational (Dediictive) I I Descriptive (Analytic) Experimental 1 I Internal External External Internal Cause to effect I Cause to effect I Hypnotism Dreams Insanity Physiological Mental pathology. Neuro-psychology Psycho-physics Psychometry. In onr acconnt of the relation of psychology to physiology we are absolutely unable to avoid some metaphysical questions; for, any discussion upon the nature of the mind involves a rational or deductive element, as much as does also any dis- cussion upon the ultimate nature of the physical elements of the brain. The attempt to analyse physiological data has resulted hitherto in vague conceptions as to inter-atomic motions, and we are taught to imagine oscillatory motion of the atoms of the substances that combine.! Similarly, the attempt to analyse psychological data has involved vague conceptions as to inter- psychical motions, and we are taiight to imagine that ideas derive their component parts from this or that structural equivalent. How far these hypotheses are supported we shall make it our particular object to inquire, and in our employment of the term ''conception" (as applied to such hypotheses) Ave do not mean thereby that we are able to form a definite picture of what takes place. We use the term in its widest sense, and faihire to conceive many of the accepted hypotheses, must be taken as failure to conceive how the requirements of one series of events are met by the events of the other series. In the study of medicine there is a preponderance of * Baldwin, " Handbook of Psychology," p. 31. t Gower, "Dynamics of Life,' p. 10. J. INTRODUCTION. the somatic element, and little or no regard is paid to the psychical element. According to Hartmann the reason of this neglect is to be found in the fact, that philosophers by profession are not necessarily physiologists, and, on the other hand, that physiologists are seldom enough of philosophers to handle their subject successfully. In the following pages everything that can tend to effect this union of characters for medical purposes is part of our object. Later we shall see that there are two ways of treating the subject of our investigation — 1st, The anal3i:ical. A\hich induces the particular from the unity of the scientific idea. 2ndly, The synthetical, which takes particulars as the starting point, and aims at reaching scientific unity. The question may be asked : Is there a science of psycho- logy ? Our reply must depend upon the meaning in its intension of the AAord psychology. If it implies a science ^\•hich deals with mental phenomena as they exist, implying also that the mental phenomena have physical correlatives, but. at the same time, taking no account of their possible explanation, then our answer would be in the affirmative, and our position would be as secure as that of any other science. Should, however, we restrict our meaning so as to regard the mind as absolute, then we pass from the region of science and imply the existence of an entity about which we can only speculate. Unfortunately, the boundaries of mental physiology extend into two spheres. In the one we have conflicting philosophical doctrines, many of AN'hich, however, may, with advantage, be consigned to oblivion ; Avhilst, in the other we have that which is empirical, and even more full of conflicting and often superfluoiis opinions. In the former department the knowledge and examination of some of the philosophical doctrines are, to a great extent, indispensable to us ; whilst in the latter our knowledge is so incomplete that, in order to attain to some degree of precision and clearness, we cannot consider a knowledge of previous opinions super- fluous. If we regard our science, however, as an empirical one. we may -with great advantage be allo\^'ed to be ignorant of what is useless; and we do not feel bound to transmit all that is believed to have been known. Every system of philosophy is subject to modifications, and. moreover, within limits, will eternally be so. To recognise. IS MIND RELATI\'E OR ABSOLUTE ? 5 and to be conscious of these limits, is another important part of onr task. By the frank recognition of what cannot be known, mnch time is spared, and much error avoided, and it is only Avhen we are sufficiently clear about the impossibility of ex- plaining many things that we shall be able to avoid vain attempts to estimate or elucidate phenomena, the explanation of which is unknowable for us, and hopelessly beyond our power. In order that we may have a firm foundation and a definite terminology, we must take every step with security, and in so doing we may be able to make some advance in our knowledge of the physiology of mental operations. We shall, therefore, after making an attempt to determine the facts and notions from which we have to proceed, begin with the most simple operations and gradually advance to the more complex. Are we to regard the term " mind " as relative or absolute y If we are to regard it as relative in meaning, it would denote an object which cannot be thought of without reference to some other object, or as part of a larger whole — i.e., just as the term •' father " cannot be thought of but in relation to " child." If this be our position, the term mind cannot be thought of apart from body,' and we are compelled to view " mind " as relative, and '"body" as its correlative. Such a distinction is no doubt convenient from a logical point of view, but from a scientific point of view it is somewhat different — i.e., the terms tree, sun, earth may be used as absolute terms in logic (i.e., having no apparent relation to anything else), but in science it would be im- possible to prove their absolute independence. From a scientific standpoint, therefore, we are not justified in regarding mind as absolute, but, as with every other phenomenon of nature, relative. If we accept the term " mind " as relative, ho\\'ever, we do not thereby extend its connotation so far as to imply a causal relation, or even a possible explanation of its correlation. In fact, we must define the term " mind" as relative only so far as we appreciate it in its relation to the body, without in an}^ waj' implying an explanation of the nature of the relation. As the naturalist knows and applies electi'o-magnetism in its relations, without comprehending its essence; as the astronomer calculates 6 INTRODUCTION. the movements of the planets, without knowing their alisolute relativity: so y\'e can duly appreciate spirit and matter in their relations to each other as body and mind, without being able to explain their actual nature or their deepest relations. Let us now, therefore, understand what is meant by mental physiology. As defined by Hack Tuke.* mental ph3'siology is one division of the great department of phj^siology. It seeks to discover the bodily organisation with which mental operations are connected. Seeing that the brain is admitted to be the organ of mind, it endeavours to trace their correlations in detail. Unconscious no less than conscious mind falls within its range. The student of mental physiolog}' makes the func- tions of the nervoiis sj^stem his especial object of study, employing for this end all the objects within his reach. He endeavours to discover the laws by ^vhich mental operations are governed, and to classify their phenomena ; but he is not con- cerned with speculative metaphysics in the usual sense of the term. Mental phj-siology, however, embraces such modern psy- chological methods of research, as are instituted to determine the relation between the action of external stimuli on the sensory end organs, and the resulting sensation or motion, as well as the reaction time of mental phenomena generally. Ladd defines the expression '"physiological psychology" as the science of the phenomena of human consciousness in their relations to the stnu:;ture and the functions of a nervous system. Carpenter, in his '• Mental Physiology." has gone a step further, and, by the consideration of mental pathology, has attempted to throw additional light upon the subject. The term "mental pathology" requires some explana- tion. Putting aside for the moment the question of depeiideiifr of the mind upon the brain, we are compelled to admit that. just as we are ignorant as to the manner in which phvsical states cause mental states, so are we absolutely without any knowledge as to the methods by which morbid physical factors gi\-e rise to morbid psychical e\"ents. By this we mean, that any complete explanation of the ultimate causal connection between the morl)id material factors and the morbid mental manifestations is impossible for us. Therefore, we must of " Dictionary of Psychological Medicine," j). 804. DEFINITION OF 3IENTAL I'ATIIOLOGY. 7 necessity view the pathology of a mental state from a psy- chical, as well as from a physical, standjooint — i.e., until we can associate the simplest mental fact with its corresponding- physical fact, we cannot hope to solve in physical terms the most simple morbid train of thought as seen in the insane, ^lental pathology must, accordingly, be viewed from two sides — namely, its psychological, and its physiological side ; and oui- hope is that we may bring the two series of phenomena, as it were, "face to face," without in any way rendering our position insecure b}^ unnecessary hypotheses as to ultimate cause and effect. The student \\-ill now recognise ho^\■ limited must be our explanation of mental and physiological facts, and that no amoiint of accuracy in detail, or any mere enumeration of a series of phenomena, will explain the nature of another series. In pursuing these inquiries, much difficulty will be experienced in our efforts to " unlearn the errors of the crowd, and the pre- tended wisdom of the schools." Scientific statements, with the sanction of scholastic authority, will prove more dangerous to us than controversial discussions on jDoints purely speculative, and in this relation Ave must appreciate that — until the proximal causal connection between the world of immaterial and material things is explained — when we depart from the consideration of the facts contained within each, and attempt to speculate upon their nature and cause, we A\'ander at once from the path of scientific inquiry into that of conjecture, and find ourselves contemplating problems, the truths of which are far beyond our reach. The psychologist and physiologist, each from his own point of view, may equally be justified in saying such specula- tions ought to be entireh'^ banished Irom their practical investiga- tions, as not only useless and improbable, but as be^'ond the reach of their faculties, and, therefore, contrary to the first- principles of scientific investigation. Our own object, I appre- hend, should be simpl}" to investigate the facts in regard to both mind and brain, and not so to misconceive the first prin- ciples of scientific incjuiry as to attempt to constinict a philosophy of cause and effect by unsound reasoning and logical absurdities. Of all the important principles which are commonly called 8 INTRODUCTION. first trutlis. the most important to lis is to be found in the answer to tlie question — " AVhat is life ? " A rigid definition of life is impossible. We can only view it on the physical side as being simply a tendency exhibited b}^ cei'tain forms of matter, nnder certain conditions, to pass through a series of changes in a more or less definite and determinate sequence. All definitions of tlie phenomenon of life are objectionable, and really mean nothing, inasmuch as they are merely enumerations of the phenomena observed, which indicate the existence of that called life. Were we in a position to answer this question satisfactorily, Ave might then ask, What is mind ? and how can we explain it? Our answer is, and must ever be. We don't know. And we never can know. In the history of psychology many attempts have been made to solve this problem. One source of fallacy has arisen, not infrequently in the actual reasonings of so-called materialists and spiritualists, whereb}^ in disproving a doctrine, they have fallen into the sophism of assuming the opposite doctrine to be true, thus making the truthfulness of that doctrine dependent upon the imsoundness of that which is opposed to it. In the light of existing knowledge, therefore, we are compelled to approach the siibject by two roads. Physiologists and psychologists must perforce study their respective sub- jects, to a certain extent, apart and in their entireties. The fundamental disparity of physical and psychical activities i-enders the explanation of the one impossible from the study of the other ; and, moreover, at the very outset, we must fully recognise, that in naming the nervous accompaniments, or physical conditions of mental phenomena, we do not fully account for them, no matter how faithfully detailed the description of such accompaniments may be. Such mere enumerations do not in the least degree aid us in the sohition of their causal connections. This does not. however, interfere with the pri- mary conee])tion that there is concomitance and co-vai'iation of physical and psychical processes. Hitherto, the attempts to prove causal relations between psychical events and physical processes have proved useless. The two are plainl}^ connected in time, but our recognition that the two conditions have tnne associations in no way explains their ultimate or causal con- DEFINITIOX OF MENTAL PATHOLOGY. 9 nectioii. Professor James says,* " The ultimate of ultimate problems, in the study of the relations of thought and brain. is, to understand why and how such disparate things are con- nected at all. But before that problem is solved, it must at least be ascertained and reduced to the lowest terms as to which mental fact and which cerebral fact are, so to speak, in immediate juxtaposition. We must find the minimal mental fact whose being reposes directly on a brain fact ; and we must similarly find the minimal brain-event which will have a mental counterpart at all. Between the mental and the physical minima thus found there will be an immediate rela- tion, the expression of which, if we had it, would be the elementary psycho-phj^sic law." A statement of all the relations which exist between mental phenomena and the changes with respect to chemical constitu- tion, structural form, and physiological function, which take place in the molecules of the cerebral areas, would constitute the foundation for an empirical science of the connection of body and mind. lyndallf says, "There is no fusion possible between the two classes of facts." AVe can trace the development of a nervous system, and correlate with it the parallel phenomena of sensation and thought ; we see with undoubting certainty that they go hand in hand, but we cannot comprehend the connection between them." Again.:}: he says, " The passage from the physics of the brain to the corresponding facts of consciousness is unthinkable. Granted that a definite thought and a definite molecular action in the brain occur simulta- neously, we do not possess the intellectual organ, nor apparently any rudiment of the organ, which would enable us to pass, by a process of reasoning, from one to the other." Spencer § holds that a unit of feeling has nothing in common with a unit of motion, and that this becomes more than ever manifest when we bring the two into juxtaposition. Let us now glance at the so-called science of physio- logical psychology Avhich constitutes a part of our empirical * " Principles of Psychology," p. 177. T " Nature," August 20, 1874, p. 318. X " Fragments of Science," 5tli edit., p. 420. § "Principles of Psychology," p. 62. 10 INTRODUCTIOX. psychology'. (1) There are, without doubt, certain psychical phenomena or processes that do not occur independently of certain material phenomena and processes, and which are not alien to the latter, but stand in obvious correlation to them, and vice versa ; and (2) there are psychical processes for which no corresponding physiological processes in the brain are con- ceivable, and v^e are not yet in a position to assert that material processes do accompany all psychical processes. Physiological psycholog}" deals exclusively ^\■ith those psychical phenomena to which concomitant physiological processes in the brain correspond, and is chieHj' concerned with variations which occur in the quality, intensity, combination, and time- order of the states of consciousness, as dependent upon the varj'ing amounts and order of different modes of physical energy as applied to the end organs of sense.* According to Ladd, plwsiological psychology is in a fair way to make out, that all psychical activity has, as its concomitant, some mode of phj'sical action, and that mental life more particularly coin- cides with the central portion of the ner\'ous series ; namely, the cerebral process. " Mental life is thus a chain of events parallel to another chain of physical events." The question as to the mental dependence or causal connections of these two series of phenomena has not been solved by scientific methods. We are not in a position to regard the psj'chical action as the result of sensory stimulation in the first stage, nor as the result of the muscular action in the final stage. Physiologists look upon the series of nervous processes as complete and satisfactory in themselves, having consciousness- as their accompaniment or collateral result. Psychologists, on the other hand, uphold the ^■iew that many psychical processes cannot be demonstrated as having any physical correlative. Spencer takes mind in the midst of all its concrete relations, and says that the essence of mental life and bodily life are one — namely, the adjustment of inner to outer relations. " The mind inhabits an environment which acts on it, and on which it in tvirn reacts." Physiologists sa}', '• No psychosis without neurosis " — and it is to the study of the exact relation between the dispositions of the architecture of the cerebral substance, * Ladd, "Pliysiological Psychology," p. 633. DEFINITION OF PHYSIOLOGICAL PSYCHOLOGY. 11 aided by physiological experiments and pathological anatomy, that they hope to become more closel}^ acquainted ^\'ith the principles upon which this mechanism operates — infer func- tion from structure, regarding the former as the natural out- come of the latter. In reply to this, Professor James points out that, no matter how numerous and delicately diiferentiated the train of ideas raay be, the train of brain events that runs along-side of it miist, in both respects, be exactly its match, and we must J30stulate a neural machinery that offers a living counterpart for every shading, however line, of the history of its owner's mind. Whatever degree of complication the latter may reach, the complication of the machinery must be quite as extreme, other^^ise we should have to admit that there may be mental events to A^iiich no brain events correspond. In accepting the theor}' of p-^t/cJio-physical iiarallelisin, we limit the parallelism to mental life, and the activities of the nerve structure of the organic world. We stop at conjectures, ^\hicll make mind co-extensive ^\ith matter, or ^\ilich make the parallelism absolute, and assign a subjective side to every atom of cosmic dust. We accept as fundamental, the psycho-phj^sical parallelism, the conservation of energy, the indispensability of introspection, and the utility of the experi- mental method. How far we are \\'arranted in assuming that the entire qualitative content of consciousness is explicable hj the association of sensational elements in conformity Avith physical laAvs, we shall venture to inquire. We shall avoid following the psychology that fails to recognise the limitation on the study of mind through matter. The application of the parallelism beyond consciousness belongs to metaphysics and epistemology. We merely postulate the co-existence in time, between the events, the physical and mental series. The tendenc}' of many authors, who seek to prove a parallelism in the evolution of life and mind, is to start the parallelism somewhere only when the biological evolution has attained a certain degree of complexity ; others, again, attempt to drop the parallelism A\hen a furthei" degree of complexity has been attained ; they then assign to the mind or body powers which on analysis are unwarrantable. If the paral- lelism is to be complete, the phenomena of human life and 12 INTRODUCTIOX. mind must be traced as correlatives from the very beginning and to the very end. There is no period in the evohition of the organism when mind can be said to appear. From time to time. Ave shall have occasion to criticise the principles of physiologists in regard to the complexity of neural action, and we shall see that mere complexity of arrangement in the refined mechanism of the brain may serve to demonstrate the ways and means of phj'siological activities ; but these principles afford ns no solution of any of the sub- jective attributes of the mind. We grant the existence of dynamical functions, and we are forced to accept many of the hypotheses advanced to elucidate the occurrence of activities in a rational and orderly sequence ; but no arguments hitherto adduced will allow us to grant that consciousness is a mere inert spectator of ph3'siological processes. We shall have occasion to criticise the general law that " no mental modification ever occurs which is not accompanied or followed by a bodily change," and we shall take account, not only of the conditions antecedent to mental states, but also of the resultant consequences of such mental states — i.e., a certain amount of brain physiology must be presupposed or included in psychology. Physiological psychology is defined as " the science which investigates the correlations that exist between the structure and functions of the human nervous mechanism and the phenomena of consciousness, and A\'hich derives therefrom conclusions as to the laws and nature of the mind." * We do not, however, infer that the science, as such, seeks as its object to form conclusions as to the nature of one series of phenomena from the study of those of the other — i.e., the study of the laws which govern matter and tlteir concomitance >rith mental acts, would only form part of the basis of the study of mind. Our task is now one of extreme difficulty. Let us compare the inanimate cerebral mass in all its structural com- plexity, to the earth with its geological strata and substrata. and for illustration let us surround them with the mind and the atmosphere respectively. Putting aside the question of their several causal connections and mutual dependence, we * Ladd, "Physiological I'sychology," p. 4. DEFINITION OF PHYSIOLOGICAL PSYCHOLOGY. 13 propose to elucidate the phenomena of the one bj^ the study of the other. Geologists divide the globe into a certain number of geographical regions or " zoological provinces," each of which is characterised by the occurrence in it of certain asso- ciated forms of animal life. In the vertical or bathymetrical distribution of animals we find that, as a rule, each species has its own definite bathymetrical zone, and it is by generalising from a large number of such facts that we are able to lay down and name certain definite zones. In addition, geologists and zoologists have to investigate the conditions and nature of animal life during past epochs in the histoiy of the world. They are enabled to estimate, with a certain degree of accuracy, how one animal differs from another, morphologically in the fundamental points of its structure, and thereby infer a physiological specialisation of function from the grade of its organisation, or they are able to formulate doctrines of evolu- tion. Similarly the phj'siologist may study the complex surface of the brain, differentiating it into functional provinces, each having its own definite zone, and he may infer a special- isation of function from the distributive development of its component parts. Further, on the one hand, the geologist may estimate ^^'ith. accuracy the correlation of certain types of structure with certain climatic or atmospheric phenomena ; whilst the physiologist attributes functions to certain nervous elements having mental phenomena as their correlatives. Is it possible, however, for the former to fully estimate the laws which govern the atmosphere, solely from- the stud}^ of the earth's crust, and the mere estimation of concomitant atmo- spheric conditions ? or, is it possible for the latter to estimate the nature of mind, and the laws which govern it, soleh' from the stud}' of the structure of the nervous mechanism, and the eniimeration of collateral series of mental activities ? Until we are able to formulate one general la^^' as to cause and effect between material and immaterial phenomena we must of necessity approach the subject from its two totally different aspects, and the closest attention to psychical laws (con- sidered as such) is as indispensable to our success as the minutest investigation of structural detail. An_v real advance is to be made only by the study of the laws of both series' 14 INTRODUCTION. of events. Physical analysis has taught ns nothing as yet about subjective states ; whilst subjective analj^sis has been just as futile with regard to objective states. Physiological psychology has as its ultimate task the apposition, and com- parison of objective and subjective states. It seeks to discover the laws which bind together processes, which in their essence have no knowable community with each other. A material bond may be conceived in connection with matter, a non-material in connection with mind, but the bridge between the two must be constructed of one or the other, or, perchance, as suggested by one eminent writer, a substance intermediate between mind and matter, which jiai'takes of the nature of both without being exclusively either. To this Mercier aptly remarks. " Imagine a thing which is partly an iron bar and partly a smell of paint without being exchisively either ! " The connection is no less real, hoA^'ever, because it is inexplicable, and no one doubts that causal connections do exist although they cannot be explained. If we look at the position, as viewed by Ziehen, all psychical processes for which there is no conceivable corresponding physiological process in the brain are to be ignored. He admits, however, that as a consequence, we do not obtain sufficient knowledge unless, in addition, we investigate certain psychical phenomena as purely psychical, but nevertheless being always aware of the possibility of some concomitant cerebral process. Empirical psychology is. therefore, to be studied under two heads. (1) Psychical processes not contingent, or demonstrably dependent, upon cerebral processes, termed by some trans- cendental psj'chology. (2) Psychical processes concomitant with, or apparently dependent upon, cerebral processes, termed the science of physiological psychology, metrical physiological psychology, or psycho-physics. Later, A\hen we discuss mind and nervous conditions in their several relationships to one another, attention will be given to the various psychological methods of research, and the psychical effects of varying con- ditions of nerve organs will be dealt with in detail. Account will also be taken of the question, as to whether the activity of all parts of the brain is directly concerned with conscious life, .or only that of certain of its structures ; or whether the organ SPECULATIVE rSYCIIOLOGY. 15 of mind includes other centimes as well as brain centres ; and we shall have recourse to the i-esnlts obtained by artificial experi- mentation, by which definite external stimuli have been employed, the subjective effects of which have been objective!}' noted and registered ; and to the pathological aspects of cerebral diseases having mental correlations. Before entering, however, wpon the questions as to the interaction of mind and brain, let us review, briefl}^, some of the hypotheses which have been derived from speculation upon the philosophical, ethical, and religious aspects of their causal connections. The spiritual theory holds, that the mind is a soul distinct in its nature and mode of activity from material things, and, in accordance with the Cartesian philosophy, the body and soul cannot act upon each other because of the essential difference between the two. By the Occasionalists, body and mind are regarded as having no causal relations — i.e., neither really acts on the other. An event of a definite kind happens in the bodily realm, a corresponding event of its own definite kind happens in the domain of consciousness, and vice versa. They are connected causally through a common ground by God. A further development is to be found in the theory of pre-estahlished /larmonj/, by which God has eternally pre- destined the entire succession of events in the world, down to every minutest detail. * Animists (a/nimo, I give life to) adopt the Stahlian theory of the soul, and regard it as the vital ])rinciple. The term "animism" is now, however, ordinarily used to express the general doctrine of spiritual agency in the operations of nature, f Mercier ^ regards the whole doctrine of so-called spiritualism as a survival, in slightly altered form, of the old superstition of demoniacal possession. Commenting upon such terms and phrases as " psychomotor-centres," ■■ ideo- motor processes," " sensation changing into movement," he says, '• Commonest and worst of all is the prevalent opinion, expressed or implied, that above the material part of the brain, somewhere in the skull cavity, there sits a little deity who * Ladd, " Physiological Psychology-,"" p. 650. t Tuke, "Dictionary of Psych. Med.,"" p. 94. i " Sanity and Insanity,"' p. 48. 16 INTRODUCTION. sends his orders out this way and that, and by some mysterious but easy process produces all the movements of the body. He plays on the centres of the brain as a performer plays on the key-board of the piano, and produces just such combinations and successions of movements as he pleases, untrammelled by natural laws. This being is variousl}^ named, according to the predilections of the writer, some calling him the Will, others the Ego, others again Conscious Personality, others the Soul ; while yet others split him up into several beings, and with the natural tendency" of anthropomorphism, not only let them make common cause against their unfortunate servant — the body — but set them fighting among themselves." The effort to evade the question of the freedom of the will arises, in most instances, from the absence of any definite concept of the nature of the subject under debate. The dilemma is, to a certain extent, extra-psychological.* Psycho- logy, however, can deal Avith the problem through analysis of the activity and selective character of choice. Were we able to eliminate motivation from our consideration, then, also, might we reo-ard determination as external and not internal. The assumption that mechanical law or determination by extraneous influences is the only conceivable tj'pe of orderly activity is natural ; the fact that, as yet, we fail to conceive of any universal law of choice, is no argument that the former assump- tion is the only solution. We find ourselves at issue with the psychologists, who regard ideo-motor action as the tj'pe of all volition, and AA'e fail to reduce all choice to immediacy without deliberation. Those psychologists who deny their own agencies in volition are fatalists, and base their conclusions upon false ideas of the relation between mechanical causation and self- determined activity. The purpose of modern physiological psychology is to try to demonstrate the relation of the mind to the brain, and, at the hands of some inquirers, the problem is solved as physiological fatalism. Others conceive themselves as mere spectators of effects determined by whatever their absolute may chance to be. The logical import of the controversies would lead us to conclude that self-determination cannot be * Prof. A.T. Ormond; "JYeedom and rsycho-Geiiesis'" — "I'sycli. Review," May, 1894. ASSOCIATIONISTS. 17 reduced to mechanical laws. The various laMs which prede- termine (through heredity and environment) the physiological and psj'chological individuality give no solution of the self- determination of choice.* The association school, of Herbart in Germany, and of Hume, Mills, and Bain, in England, has constructed a psj'-chology in which the soul or e(jo of the individual is no longer viewed as the pre-existing source of the representations, but rather as their last and most complicated result. Its disciples endeavour to show how such things as perceptions, emotions, volitions, etc., maybe engendered in an individual by the cohesions, repulsions, and forms of succession of discrete " ideas " and without the aid of a soul. Materialists seek to reduce organic life to the effect of mechanical arrangements, and they regard mind as an effluence from, or product of, the activit}^ of this material substratum. The}^ regard the constitu- tion and activities of molecules, as determined by the inter- action of the ultimate atoms which comprise them, under the law of the conservation and correlation of j)h3'sical energy. Whenever a certain constitution and consequent modes of activity are brought about in the molecules, under this general law, then it is of their own comprehensible natui^e to exhibit, in addition to the various forms of motion known as nerve commotion, another class of co-existing phenomena, called mental phenomena.! Later, we shall see that the arguments of even the most advanced materialists, who regard thought as the effect, or result of cerebral movement, are insufficient to afford the slightest explanation of any subjective mental state. " The whole circle of consciousness is,"' says Baldwin, " an added fact to that of movement." Many of the materialists ridicule the idea of an immaterial mind acting upon a material bod}' ; but they do not hesitate to affirm that a material body can act on an immaterial mind. If we look more closel}' at the physical laws of " correlation of energy " we at once see that they afford us no help in the * See Baldwin, " Handbook of Psychologj%" vol. ii. pp. 352—376 ; Hodgson, " Free Will : an Analysis "— " Mind," April, 1891. t Ladd, "Pliysiological Psychologj'," p. 654. 2 18 INTRODUCTION. solution of the causal relations of mind and matter ; for we must classify all forms of physical energy according to their quality, nature, degree, and amount of their motion; and we are unable to demonstrate or define states of consciousness in the same manner as modes or amounts of motion, and, in conse- quence, we cannot attempt a strict mathematical correlation between phj^sical motion and such states of consciousness. In the endeavour to bridge the gap between the molecular energy of organic material and that of the mode of activity of mind, the various mathematical formulas, under the laws of conserva- tion and correlation of energy, have been unwarrantably extended in their application. Further, as Ladd puts it, " Psychology teaches that the world of mental objects — the only world of immediate experiences — is built up by the synthetic activity of mind ; it calls upon the physicist to remember that he has no other way of reaching these atoms and of discovering the laws of their relations except by the path of mental activity ; and it reminds him that this activity cannot escape the control of mental law.*' In addition to the spiritualistic theory that so-called inani- mate objects are vitalised by a principle which involves purpose or end, and the materialistic view, of mind as the result of an activity of complex physical forces, we have combinations which aim at giving equal substantive reality and power, both to the spiritiial and to the material. In the theory of dualism we find a combination of the two substances, which are viewed as existing side by side, but as exerting no influence the one on the other, the appearance of interaction being cine to Divine arrangement. The molecules of the brain act, dynamically, according to their own constitution and modes of arrangement. The mind, on the other hand, as a real entity of another order, has the various states of con- sciousness as its acts ; and, according to the more recent doctrines of dualism, the two series of phenomena are cor- related. The nature of the correlation is unknown, but it is assumed that the mind and brain act in view of each other: the action of the one accounting for the action of the other in some unexplainable and unknowable wa}^ There are three forms of dualism — viz., (1) The metaphysical, which takes account of MONISM. 19 mind find matter ; (2) The philosophical, which takes acconnt of the body' and the sonl ; and (3) The ethical, which concerns itself with good and evil. The desire to connect the two metaphysically has given rise to the doctrine of monisHl, according to which, one reality has two aspects — i.e., material phenomena and mental phe- nomena are related as two attributes of the same substance. This implies the existence of a substance composed of two utterly incomparable series of phenomena, and to regard this substance in the terms of either series must resiilt necessaril}^ in arguments from the point of view of the spiritualist or the materialist. Wundt recognises three types of theory: Material- ism, Spiritualism, and Animism, the former two each having a dualistic as well as a monistic form. Bain, on the other hand, forms two main groups — viz.. Those which adopt two substances, and those which assume but one. Let us now venture to look at the subject for ourselves and ask ourselves. Is there any test whereby we can distinguish between a physical or physiological and an intelligent act? Many hold the view that the pursuance of future ends and the choice of means for their attainment are the mark and criterion of the presence of mentality, and that no actions but such as are done for an end and show a choice of means can be called intelligent. Professor James says : " If we find ourselves unable to banish the impression that there is a realm of final purposes, that we exist for something, we place intelli- gence at the heart of it and have a religion. If, on the contrary, in surveying its irremediable flux,* we can think of the present only as so much mere mechanical sprouting from the past, occurring with no reference to the futiuT, we are atheists and materialists." The same author regards con- sciousness as having a causal efficacy, and as being at all times primarily a selecting agency. " Every actually existing con- sciousness seems to be a fighter for ends, of which many, but for its presence, would not be ends at all." In fact, consciousness directs its own machinery. " The spiritualist may believe in the soul if he will, the pessimist may say that Nature, in her unfathomable designs, has mixed us of clay and flame, of * " Irremediable flux " is essentially pessimistic. 20 INTRODUCTION. brain and mind, that the two things hang indubitably together and determine each other's being, but how or why, no mortal may ever know." Undoubtedly, the niitrition of the tissues, the circulation of the blood, and the secretion of different kinds of fluids are dependent, to a great extent, upon the states of the mind ; and, later, when we come to study the influence of the mind upon the body, we shall find that, if, with sluggish and abnormal digestion, we have mental depression, it is equally true that an attack of melancholia will retard and pervert the processes of digestion ; and, similarl}^, emotional conditions, stress or strain, may impair the cerebral mechanism and its functions. In opposition to these more or less spiritualistic views we have the authority of Professor Huxley, who says that in animals, their volition, if they have any, is an emotion indica- tive of physical changes, and not a cause of such changes. We are, therefore, regarded as conscious automata. " Our mental conditions are simply the symbols in consciousness of the changes which take place automatically in the organism. In men, as in brutes, there is no proof that any state of conscious- ness is the cause of change in the motion of the matter of the organism." We can also add, it is not possible to form any conception as to how any state of consciousness can aflect the cerebral molecules, and, moreover, we never shall be able to surmount or explain this difficulty ; but our inability to explain such action does not negative its possibility. The view, how- ever, that the feeling we call volition is not the cause of a voluntary act, but the symbol of that state of the brain which is the immediate cause of that act, is open to any number of arguments. Professor Clifford states, dogmatically, that the only thing which influences matter is the position or motion of surrounding matter, and " if anyone says the will influences matter, the statement is nonsense." " Were this the case," remarks Professor James, " the mind's history would run along- side the body histor}^ of each man, and each point in the one would correspond to, but not react upon, a point in the other," and we agree with him that, " in the present state of psy- chology- to urge the automaton theory upon us on purely . 179. 22 INTRODUCTION. determine the laws which mutually or individually regulate the two totally different series of phenomena, and thus, b}" bringing them into apposition, endeavour to establish a psj-cho-physical law which shall embrace the requirements of both series of events. Many of the existing psycho-physical formula? are the results of unsafe hypotheses -within the domains of psy- chology and physiology respectively. The student will find that the blind ends of physiology and psj^chology are covered respectivel}^ by anverifiable hypotheses, and that it is with the comparison of these blind ends that he has to do in estimating the ultimate nature and correlation of bodil}' and mental events. Our ideas of the brain, and of its relation to the mind, are derived mainh^ from some sho^^y results of modern science ; but the modern scientist too often forgets that processes are no explanation of results. The theorists who evolve man from an ape see no likelihood that he will ever become an angel. Under the dogma of their one great law the}^ settle the history of the past, and negative the possibilities of the future. Mate- rialists say that the mind is derived from, or correlated to, atomic movement, and in order to prove a causal nexus they bring the analogy of the cosmical mechanism to bear upon the cerebral atoms. The}^ seek to prove the existence of a mind correlated to the infinitesimally- minute counterpart of the cosmos ; but there they end. They do not coun- tenance any speculation as to the existence of a universal mind correlated to the infinite system from which they draw their analog}". That our minds ha\e a physical basis, without which their phenomena M'ould not exist for us. is as true as the statement that life itself has a physical basis, without -which it would not exist for us. Beyond this we cannot go, and the state- ment that mind depends upon the body in no way implies an explanation of the ca/asal connection between the two states — i.e., to state that one condition depends upon another is not to explain hou: it depends. The doctrines of concomitunce, imra.l- lelism, and simultaneity furnish us with an explicandmn and not an ex])lica,tio. Since an explica.tio is impossible, we must devote ourselves Avith an equal amount of attention to the stud}" of MATERIAL MONADISM. 23 the heterogeneous states of mind and matter ; and, in our endeavour to bring them into apposition, we must not venture upon any such explicatio. Finally, it is happilj- obvious that oiir knowledge of the brain and its structures is graduall}^ becoming more extensive. The anatomico-physiological school is striving to provide us with data, with the aid of which it is hoped we may be able to correlate mental facts. The explanation of the absolute reality of physical and psychical acts must remain outside physiological and psychological theories. The physiologist seeks to demonstrate the paths of conduction and dissemination of physical forces.* The psychologist seeks to demonstrate the method by which we think ; whilst, lastly, the physiological psychologist seeks to establish some relationship between the two processes, without in a.\\j way attempting to throw light upon their ultimate nature or causal origin. * See Batty Take, " On the Insanity of Over-exertion. ' 24 CHAPTER I. Anatomy of Cortex. Arrangement of Cortical Structures — The Nerve-Cell — Processes of Nerve-Cells — Nerve-Fibres — The Relation between Cells — The Neuroglia, or Connective Tissue Basis Cell Elements — Caudate Fibre-Cells — Stellate Fibre-Cells — Protoplasmic Glia Cells. Physiology of Nerve-cell. Nutritive Function — Transmission of Nerve Impulses — Excitability and Conductivity — The Functions of Nerves — Negative Variation. ANATOMY OF CORTEX. Before examining whether the areas of the cerebral cortex are allied with particular functions of the mind, it may be well for us to examine, somewhat carefully, the physical side, so that we may build our conceptions upon the basis of facts known to us. If we are to regard the mind as having its seat in the brain, we must study the material elements of which that seat is composed. Starting with the assumption, justified by scientific observa- tion, that the mind, as j^erceptive, has its seat within the nervous sj'stem, and that of this system the structural elements of the cerebral cortex have the greatest claims to being con- sidered as immediately concerned with the occurrence of mental phenomena, it will be advisable to give some account of what is known as to the microscopic and chemical nature of these brain-elements. To enter into a description of the entire encephalon, with its membranes, vessels, tracts, and subordinate regions, would obviously be out of place here. Neither can we deal thoroughly with the anatomy of the convolutions, our knowledge of which has been so much ARRANGExMENT OF CORTICAL STRUCTURES. 25 advanced by the labours of Gratiolet, Ecker, Tiirner, Broca, Bevan Lewis, Ramon y Cajal, de Vaillet, de Mosso, Golgi, and others. Comparative investigations, in reference to the struc- tural differences of the various regions of the cortex, have proved of great importance. The progression in complexity of structure, as we ascend the scale of animal organism, is significant, and the comparison of the structure and functions of the brain in different animals leads us to fairly definite conclusions concerning the human brain. We are almost compelled to believe that differentiation of cerebral function implies likewise a structural differentiation ; but, as we shall see later, we do not yet understand the design of structural differentiation, as allied with psychical events. With the evolution of certain mental manifestations, we look for a corresponding advance in complexity of arrangement of the material elements. " Thus it is," says Bevan Lewis, " we expect the physiological areas ascertained by Ferrier to exist in the brain of the monkey and other animals to exhibit a structural differentiation characteristic of those parts, and hence helpful in the recognition of analogous regions in other orders. If it can be established that areas whose functional endowments are familiar to us present imiformly specialised anatomical features, we may reasonably conclude that other structurally differentiated areas, whose fimctions are unknown to us at present, nevertheless have each and all of them diverse endowments." In urging the importance of making ourselves acquainted with the intimate structure of the cortex, he pays this tribute to physiological experimentation that it alone can lead to conclusive results. " An attempt to delineate the homologous areas of the cortex in the different orders of mammalia by simple inspection would (on a priori grounds) only lead to failure ; indeed, errors have already been fre- quently committed with respect thereto. Arrangement of Cortical Structures. — To Ramon y Cajal, Retzius, Golgi. and Dejerine, we are indebted for the latest descriptions of the arrangement of cortical cells. Cajal describes four layers of cells in a typical Rolandic convolution — viz. : (I) A superficial zone, containing a few small fusiform cells, surrounded by numerous neuroglia nuclei ; their long j 26 ANATOMY OF CORTEX. axis lies parallel to the plane of the surface, and they give off an apical and a basal process, which arises from the proto- plasmic exjjansions, and not directly from the body of the cell. These processes never descend into the other layers, but run horizontall}^ or slightly diagonally for a considerable distance, and in their course give off collateral branches, which form a rich terminal plexus. Collaterals are also sometimes given off by the axis-cylinder, -s^'hich breaks up into two or three branches. Cajal also describes numerous polygonal, triangular, and unipolar cells belonging to this layer. (2) The second zone contains a number of small pyramidal cells, with apical processes, which end in tufts in the super- ficial layer. Collaterals are given off from these apical processes, and also from the axis-cylinder process, just as in the superficial layer. The lateral expansions end \\dthout anastomosing with similar exjjansions of other cells. The "broad stripe" of Baillarger corresponds to this plexus. (3) The third zone, or the zone of large pyramidal cells, resembles the second zone, except in the size of the pyramids, which are known as " tM ATIC). dr, dendrons; n, neuron; coll., collaterals. (Slightb/ modified from Schiifer.) Golgi, ^^'ho was the first to describe the relative size of the neurons, regarded those cells with comparatively long neurons as being concerned with the giving out of efferent impressions ; those with relatively short and soon-branching processes as being- sensory or receptive in function. Schafer employs the term " intermediary cell " to imply that, the cell in question offers an intermediar)^ link between centripetal impressions, which may be brought to a nerve-centre by the neuron of a sensory pro- jection-cell, and centrifugal impressions which pass awaj^ from the nerve-centre by the neurons of motor projection-cells. 3 34 ANATOMY OF COETEX. Ramon y Cajal lias given the term " collaterals " to the fine brandies wliicli are now demonstrated as coming from the neuron. The difference in appearance between the two kinds of processes, when prepared by the Golgi method of staining, is readily detected by an experienced observer. The dendrons Fig. 3. Ckll of Irregular Pyramidal Type. d, dcnrlrons tenninating in feathery arborisations ; ?i, neuron ; coll., collateral. (After Berkhij.) usually have a rough outline, ^\'liile the neurons are generallj^ smootli. The neurons remain comparatively unchanged in diameter along their course, whereas the dendrons branch repeatedly, and hence gradually diminish in size (Fig. 3). Nerve-Fibres. — Nerve-fibres represent to us a conducting apparatus, and they form a means of connection between the central nervous organs and the peripheral end organs. Of nerve-fibres we have two kinds : (1) non-medullated nerve-fibres, and (2) medullated. Of the non-medullated form, the simplest is that of the primitive nerve-fibril, which is very delicate, and is often found exhibiting small varicose swellings in its course. These fibrils form by the splitting up of the axis-cjdinder of the nerve-fibre near its termination, as seen in the terminations of the olfactory fibres, in the optic nerve-layer in the retina, in the corneal nerves, and in the terminations in non-striped muscle. Similar filires are also to be found in the finely divided processes of nerve-cells in the grey matter of the brain and NERVE-FIBRES. 35 spinal cord. A second variety is to be seen in the axial- cylinder process of nerve-cells, in which primitive fibrils are held together in bundles by a slightly granular cement, which gives them a very delicate longitudinal striation and finely granular appearance. These are termed naked, or simple axial cylinders. Kemak has described a third variety in the pale non-medullated fibres which are foiind in abundance in the sympathetic nervous system . They consist of an axial cylinder which is inclosed by a delicate, structureless, and elastic sheath, corresponding to the sheath of Schwann. Ranvier, however, denies the presence of this sheath, and believes that the nuclei are merely applied to the surface, or slightly embedded in the supei'ficial parts of the fibre, and that they belong in reality to the fibre itself. These differ from medullated fibres, inasmuch as they branch and form an anastomosing network. When acted upon by silver nitrate they never show any crosses. Medullated fihres occur, also, in several forms. In the white and the grey matter of the brain and spinal cord we meet with axis-cylinders, or nerve-fibrils, covered only by a medullary sheath or white substance of Schwann. These ai*e also called varicose fibres, from the fact that after death they often present varicose swellings due to the accumulation of fluid between the medulla of myelin and the axis-cylinder. They are medullated nerve-fibres without any neurilemma, and they have nodes of Ranvier. The great mass of the cerebro-spinal nerves, how- ever, is largely constituted of medullated fibres having the sheath of Schwann. These fibres are highly refractive, homogeneous, and exhibit a double contour, their margins being dark and well defined if acted upon by reagents. Each fibre consists of (1) Schwann's sheath (neurilemma or primitive sheath), which is thin, clear, and has nuclei in it ; (2) medullary sheath, or white substance of Schwann, which surrounds the axis-cylinder and has been compared to an insulating medium round an electric wire. This substance is quite homogeneous, glistening, and refractive. It is of fluid consistence, and this fluid can be scpieezed out of the cut ends of the fibres in spherical drops. After death this substance shrhiks slightly from the sheath and breaks up into droplets, not due to coagulation, but, according to Toldt, to a process like emulsification, the drops pressing 36 ANATOMY OF CORTEX. against each other. It contains a large amount of lecithin and cerebrin, which swell up to form myelin-like forms in warm A\'ater.* It also contains fatty matter, is blackened by osmic acid, and rendered transparent by chloroform, ether, and benzine. The axis-cylinder, which lies in the centre of the nerve and is essential to it, is usually cylindrical and composed of fibrils united by a cement of semi-fluid consistence. Kupffer de- scribes a fluid — " neuro-plasma " — which lies between the fibres. According to other observers, however, the whole cylinder is inclosed in an elastic sheath, peculiar to itself and composed of neuro-keratin. f To this sheath Kiihne has given the term (ixi-lemma. There are, in addition, certain structural modifi- cations which require notice. The nodes or constrictions of Ranvier occur at regular intervals along a nerve-fibre. At these points of constriction the Avhite substance of Schwann is interrupted, so that the sheath lies upon the axis-cj'linder. The presence of one or more nuclei in each inter-annular or inter-nodal segment has led to the belief that the whole segment is equivalent to one cell. These nodes are regarded as being concerned with the diffusion of plasma through the outer sheath into the axis-cylinder, and the giving off of the decomposition products. Each segment is looked upon as lieing built up of a series of conical sections, each of which is bevelled at its ends. These bevels are arranged one over the other in an imbricate manner, showing slight intervals between. The oblique lines running across the white substance are termed the incisures of Schmidt or Lantermann. In addition to the nucleated nerve-corpuscles, which are found at intervals under the neurilemma, other nerve-corpuscles or "demilunes" have been described as quite distinct. These latter are stained yellow by safronin, while the ordinary nerve-corpuscles are stained by methylanilin.ij: Ewald and Kiihne state that the axis-cylinder, as well as the white substance of Schwann, are covered with an excessively delicate sheath of neiiro-Jxera.tin, and the two sheaths are connected by numerous ti'ansverse and oblique fibrils which permeate the white substance. The nature of the fibrillated appearance of the axis-cylinder, * Laudni.s iiiid Stirling, -Srd edit., ]). 528. t Il)id., J). 527. X Ibid., p. 518. IsERVE-FIBRES. 37 as seen both in neurons and dendrons, is still a matter of conjecture. Max Schultze regards the axis-cylinder as con- sisting of two substances — viz., a bundle of fine fibrils (ultimate fibrillae) which serve as conductors, embedded in a clear sub- stance like protoplasm ; and his observations upon the structure of the non-medullated fibres of the olfactory nerve, and of the axis-cylinder of the ordinary medullated fibres, go to prove an anatomical discontinuity of the fibrils. Schiifer argues that this is further borne out when we trace the ramification of the nerve- fibre at its peripheral extremity; as, for example, in the cornea, and even in the nerve-endings of the motor nerves upon the so- called end plates, where there is to be seen a complete separa- tion of the fibrils \^hich have composed the axis-cylinder, and which end here in the ultimate branchings of the axis-cylinder. The occurrence of varicosities upon the nerve-fibrils is regarded as an additional proof that they are excessively fine-walled tubules filled with fluid. The opposing views of Heitzmann, Leydig, Fromann, and Nansen, are, that the nerve-fibrillge of the axis-cylinder are nothing but a repetition of the reticulum of fibrils, as seen i,n the protoplasm of all nerve- cells ; the reticulum having, in this case, been drawn out to such an extent that its meshes have become extremely elongated, and its fibrils, to all appearance, parallel and dis- tinct.* Nansen believes that the apparent fibrils are really the optical longitudinal sections of sheaths or septa of spongio- plasm, which subdivide the fibre into tubes filled with hyalo- plasm, which forms the true conducting material of the nerve- fibre. Engelmann f agrees that the fibrils appear to be distinct, and are never seen to anastomose or form a plexus of fibrils. He does not see, however, how these subdivisions of the axis- cylinder can fulfil any separate function as the conductors ot nervous impiTlses, on account of the closeness of their contact, and the smallness of their number, as compared with that ot the fibrils into which the fibre breaks up at its peripheral termination. :j: From the experiments of Engelmann, by treat- ing the axis-cylinders with nitrate of silver, the question as to * Schafer, op. cit., p. 144. t " Pfliiger's Archiv.," xxii. p. 26. X Ladd, " Pliysiolog. Psych.," p. 40. 38 AXAT03IY OF CORTEX. the continuity of the axis-cylinder throngh the nnnnlai' con- strictions is by no means settled. The fact that tlie axis- cylinders, as a rule, when treated in this way. were broken off at the annular constrictions does not disprove their discon- tinuity, and possiblj^ there may be exceedingly minute hour- glass constrictions at these nodes. These fibres are regarded as composed of a number of annular segments cemented together — each separate fibril placed exactly end to end with its felkn\' in the adjoining segments — and possiblj- such an arrangement would accord with the theory which regards the segments as elongated and developed nerve-cells. Bevan Lewis regards the question of the homogeneity or, so to speak, of the fibrillated constitiition of the axis-cylinder as of fundamental importance, and if we are to look upon such fibrils as isolated tracts of conduction throughout their length, the nerve-fibre and the cell itself have a far different significance.* He points out that risible continuity of the fibrillas is not essential. More or less fusion may occur throughout the length of the iihre ; and the splitting up into fibrilla3 may only be observed at the centric and peripheric terminations as an indication of the fibrillar constitution of the axis-cylinder and its lines of molecular disturbances. The significance of Fromann's lines is unknown. These lines are to be seen as transverse markings when the axis-cylinder is treated with nitrate of silver. The silver solution seems to penetrate at the nodes, where it stains the cement substance and also part of the axis-cylinder, giving the characteristic striation. The Relation between Cells. — The relation which nerve-cells bear to one another is important though still some- A\-hat doubtful. Of late, however, much valuable work has been done in this direction, and much evidence has been accumu- lated to show that — (1) there never is direct iniion of nerve-cells by distinct and comparativelj" coarse fibres ; (2) there is no union of nerve-cells by means of the ramifications of the fine dendrons, which formerlj' were supposed to pervade the whole gre}' matter of the nervous system as a fine fibrillar net-Avork ; (3) every nerve-cell, with all its processes, is a distinct and isolated anatomical unit.f Schiifer believes that, with great * Op. cit., }). 92. t Schafer, op. cit., p. 147. THE RELATION BETWEEN CELLS. 39 probability, the only connection of one nerve-cell with another is a physiological one, and that it takes place by the adjunction of the arborised process or processes of one nerve-cell, either \\'ith the cell-body of another cell, as in the cerebellar cortex, or by the adjunction and interlacement of the arborised processes of one nerve-cell with similar arborised processes of other cells, as in the olfactory glomeruli. In fact, ^\e may regard the basis of the grey matter of the nervous system — the granular-looking substance in which the nerve-cells are embedded — as an ex- tremely fine interlacement of ramified processes, not only of the nerve-cells which actually lie in that particular grey matter, but also of nerve-cells M-hich. lie in other parts of the nerve- centres, or even in the peripheral parts of the nervous sj'stem, and which, on arriving at the grey matter, break up into a fine arborescence of nerve-fibrils. * The lieuroglia or connective basis is, according to Bevan Lewis, composed of a structureless or finely molecular hasis-substaiice, and connective cell and fibre neticorks, which act as a supporting and protective material, and differ in special qualities in different regions. In the spinal cord the binding material is in the form of large-sized nucleated cells, with numerous lengthened ramifying processes, together with a plexus of fine fibrils ; whilst a structureless or very fineh^ granular material is found here but sparingly. Nearer the periphery of the cord this connective sheath becomes more fibrillar. In the grey matter of the cord, and in the gre}' matter of the cortex, the molecular basis preponderates over the fibrillar elements of the neuroglia ; whilst in the medulla of the brain the amount of connective-fibre element exceeds that of the molecular element. In affirming that this basis- substance (Piinktsubstan?:, of Leydig), is finely molecular and structureless, Bevan Lewis hardl}-, perhaps, pays sufficient tribute to the numerous observations ■sA'hich have accumulated since the emplojnnent of the methods of Ehrlich and Golgi. By these methods the so-called Pimlisubstanz is shown to be made up of the ramifications of fibres derived from the neuro- dendrons of the large motor nerve-cells. The PtinMsubstoMz is now general!}^ regarded as being made up of the ramified processes and their somewhat varicose ends. These processes * Op. cit., p. 148 40 ANATOMY OF COKTEX. are part of the nerve-cells of the central ganglia, and also of the nerve-cells at the periphery. The observations of Retzins, Rohde,* and Biedermannf also snpport this view. The cell-elements of the nenroglia are of two kinds, and these differ from one another in regard to size and connections. The smaller of the two kinds of cell vary from 6/x to 9/x in diameter. Their nucleus is spheroidal and relatively large, and it is surrounded by an extremely delicate protoplasmic invest- ment. According to Bevan Lewis, these cells are to be found in three situations : (1) irregularly in the neuroglia frame\\'ork ; (2) in regular series round the nerve-cells ; and (3) in more or less regular succession along the course of the blood-vessels (capillarA* and arteriole). The larger cells are usually lo/i. in diameter, and have a relatively larger amount of protoplasm as compared with the size of the nucleus. These cells are also fre- quently flask-like in appearance, and may contain several niiclei. Their processes are numerous, extremely fine and radiating. The want of aiSnity of these elements for the staining agent (anilin) has led to the conclusion that they are non-nervous in character. By the employment of a modification of Golgi's method of staining, Andriezen has demonstrated two great morphological groups of neuroglia elements, which he has termed (rt) neiiroglia fibre-cells, and (h) protoplasmic neuroglia-cells. Of the neu- roglia fibre-cell he describes two species. One species is situated in the first layer of the cortex, and sends its streaming- fibres down into the third layer : these are the caudate fibre- cells (Fig. 4). The other species is situated in the medullary substance or white matter, and has radiating fibres passing in all directions : these are the stellate fibre-cells. The caudate p'hre-ceUs form a distinct feature in the first layer of the grey matter. The bodies of the cells are embedded in the grey substance, and their apices are rounded and pointing downwards, thus giving rise to '• tail-like tufts "' of smooth (Hires, which pass into the deeper laj^ers of the cortex. From the wider ends of the bodies there arises a system of radiating tangential fibres. Andriezen describes the individual fibres * "Histologische Untersuclumgen liber das Nervensystem der Poly- cliiiten," Breslau, 1887. t "Jenaische Zeitschr. f. Naturwissensch.," 1891. THE RELATION BETWEEN CELLS. 41 as extremely long, smooth contoured, and of uniform calibre thronglioiit; as being of remarkably uniform thickness one with another, nnbranched, slightly wavy in their course (which is, on the whole, almost rectilinear), and as exhibiting here and there small sharp ciirves and small angular bends, while sharp trans- verse fractures are not infrecjuent. These fibres formed a line cortical fretwork, and none of them could be demonstrated as forming an anastomosis, nor did they appear to have any special vascular connections. The stellate Jihre-cells have small and indistinct bodies, mainly constituted by the enormous number of fibres which l^in. 2"^^. Fig. 4. THKEi: Neuro(;lia Fibre-Ceixs. «, caudate cell ; b and c, transitional forms between caudate and stellate fibre-cells ; \st L, first laj'er ; 2nd I., second layer of coitex. (After Andriezen.) meet and intercross them. Many of the neuroglia fibres pass through the cell-body. According to Andriezen these are remarkably like the fibres of the caudate fibre-cells in calibre and contour, and exhibit the same peculiar sharp curves and angular bends in a course otherwise straight, and also the same transverse fractures. They stain of the same colour, never branch or anastomose, are of considerable length, and do not exhibit the special vascular attachments which the protoplasmic o-lia-cell exhibits. 42 ANATOMY OF CORTEX. The protoplasmic cell (Fig. 5) is said by Andriezen to occur abundantly throughout the grey matter of the cortex, and but rarel}^ in the medullary substance. It is of mesoblastic origin, and exercises a lymphatic function. Its processes are stellate or dendritic in arrangement, and the lymph-spaces which surround its coarse, shaggy processes, are in direct communication with the perivascular lymphatics. Be van Lewis regards these large protoplasmic cells as forming the actual extremities of the lymphatic system, and he maintains that their thick processes end in the perivascular or hyaline sheath, whilst the finer reti- culated processes extend through the neuroglia network. Fig. o. Protoplasmic Glia-cell from the Human Brain (1st Laykr of Cortex), showinCt One Expanded Disc-like Attachment to a Vessel. {After Andriezen.) These protoplasmic glia-elements are regarded by Andriezen as being the elements which exhibit a morbid hypert^i'ophy in pathological conditions (alcoholism, general paralysis). They also show further morbid activities, in the last stage of which their protoplasm deposits numerous organised fibrillar, in the act of doing which the protoplasm proper is used up. A scanty remnant may persist, ghost-like, to mark the position of what was once a protoplasmic cell-bod}*.* These protoplasmic cells are now regarded as lymph-secreting cells. Andriezen believes that the cell absorbs or takes up lymph from the brain-tissue Avhich it permeates, and that it discharges it, through its peri- dendritic canaliculi, into the perivascular Ijnuph spaces. * Andriezen, " British Medical Journal, " July, 1893. PHYSIOLOGY OF THE XEin'E-CELL. 43 Other small glia-cells, sometimes mistaken for leucocytes, Avitli sharply-defined niiclei and a small quantity of protoplasm, have been described as surroundino- the larger nerve-cells as they lie in their pericellular sacs. Their function, however, is unknown.* Bevan Lewis regards the ^Drotoplasmic cells as comprising the distal extension of a Ij^mphatic system, and he has clearl}^ pointed out that arrest to the escape of perivascular Ijnnph from the cortex is immediately followed by a morbid development and by a hypertrophic condition of these " spider cells." The question of the significance and nature of these cells in morbid conditions has been freely discussed of late. Bevan Lewis atti'ibutes to them an active and aggressive part in the pro- duction of disease, and thereby somewhat enlarges the notion of their function as " scavengers " to remove waste products. The more generally accepted opinion, however, is that their role is probably a secondary one, and that they remove rubbish instead of producing it.f PHYSIOLOGY OF THE NEPtVE-CELL. Nutritive Function. — The nerve-cell's most important function is that of nutrition, and the presence of a nucleus seems to be essential to this. When a nerve-fibre — i.e., a process of a nerve-cell — is cut — no matter whether, in its normal state, it conducts impulses to or from the cell — the part which is cut off from the parent cell must die. This nutritive function of the nerve-cell has been insisted upon by Nansen.ii: M^ho believes that the cell-body has no other function than that of effecting the nutrition of the whole cell, and more particular!}- that of the axis-cylinder process. Schiifer points out that although the nutritive function may be the one essential function of the nucleated body of the nerve- cell, there are many cases in which the bod}' of the cell also serves for the transmission of nerve-impulses. As examples, he gives the bi-polar cells, through which impulses must of neces- * Andriezen, "Brain," 1894, p. 664. t Carter, " Brain," 1893, p. 399. J " Histological Elements of the Central Nervous System," Bergen, 1887. 44 PHYSIOLOGY OF THE NERVE-CELL. sity pass ; and the motor projection-cells of the spinal cord and bulb, in which instances nerve-impulses are probably commitni- cated to the body of the cell from the interlacement of nerve- fibres, derived from other cells, which enfold the body of the motor cell. Whether nerve-impulses really traverse the cell body is still open to discussion. Schafer believes that in some instances nerve-impulses can be transmitted along nerve-fibres without traversing a nerve-cell at all, and he even goes a step further, with the conception that sensory-impulses ma}^ become con- verted into motor-impulses within the PuuMsuhstanz without necessarily traversing the motor nerve-cells at all; the latter being only connected \\'ith the Punktsubstanz by dendritic collaterals, which pass off from their large neuro-dendritic processes. Our knowledge of the modes of neural motion — i.e., the methods of propagation of nerve-impulses — is absolutely untrustworthy, and we have yet to solve this problem. Hence we readily see that before an attempt is made to find the solution of psy- chical phenomena in terms of neural molecular motion, we must arrive at some more definite conclusions as to the nature and workings of the material structure. Excitability and Conductivity.— The two forms of molecular motion which characterise both nerve-fibres and nerve-cells may be called excitability and conductivity. The former is looked upon as the motion originally set iip in the nervous elements, and corresponds to the excitation of a stimulus ; the latter represents the propagation or conduction of this initial excitation along tracts to other regions. The external and internal stinvidi, and their relation to excitation, will be dealt with later. Here, however, we must ask the question. Do nerve-cells act as generators of nerve-impulses ? It is almost universally held that they do, in which case such commotions are regarded as being essentially automatic. Let us take, as an example of automatic action, the action of the respiratory ceiitre, and let us endeavour to eliminate from it all sources of stimulation from without. In order to do this we must exclude the chemical stimulation which results from varying conditions of the blood : we must also cut off the possibility of stimuli reaching the centre from EXCITABILITY AND CONDUCTIVITY. 45 the periphery, or from an}- other regions whatever. When we have direct proof that nerve-impulses are generated in the nerve-cell under such circumstances, then only shall we be able to say that such impulses arise automatically. The end organs of sense are excited specifically b}" their appropriate stimuli ; the afferent nerves have their specific function of conduction from these end organs of sense; the efferent nerves have their specific function of conduction from the central organs, and we are not in a position to say that nerve-cells ever do give rise, without some mode of stimulation, to automatic action. We have alreadv seen that nerve-impulses may be transmitted without passing through the nerve-cell at all ; and, further, the power possessed by the bod}^ of the cell of transmitting impulses, when stimulated, is not unique in it, but is equally shared by its processes under precisely the same conditions. " It is," says Schafer, " a function which is not special either to the cell body, or to the processes, but is common to both."* When a stimulus is transmitted by a ganglion-cell, so as to impart motion, such action is termed reflex, and the ganglion- cell is said to possess rejiex function. This form of action is the simplest nervous process with which we shall have to deal. Stimulation and reaction are the main conditions of nerve life, and they are essentials of nervous function. Throughout the ^^'hole of animal life we see this function exhibited in its innumerable modes and degrees. The mere recognition, how- ever, of this fundamental property, as pertaining to all life, does not imply any explanation of the phenomena in terms either physical or psychical. The phenomenon is essentially the same in its rudimentary form in the amoeba3 as in its more complex developments through the paths of conduction in man; and we must never lose sight of this fact, that no matter how clear our knowledge may become of the excitations of stimuli, of the methods and directions of their conduction, and of their numerous expressions as forms of motion, we are in reality no nearer the solution of the all-important problem — the ultimate * Eckhard made a distinction between the automatic-tonic and automatic- rln/thmic functions of the ganglion-cells, according as the movements over which the cells exercised control occurred at irregular or regular intervals. 46 PHYSIOLOGY OF THE NERVE-CELL. conditions of vital reaction. On the physical side we imagine that within the nerve-cell afferent impulses become modified as to number and character by profound molecular changes, so that they become transformed into efferent impulses of another kind. In reality, however, we do not know how the effects of stimuli are conveyed to the ganglion-cell ; we do not know what becomes of the excitations within the ganglion-cell ; nor do we know how the modified afferent impulses are propagated to their destinations. When we come to consider the phe- nomena of mind, and discuss the various physiological theories which have been advanced to explain those phenomena, we shall see that the endeavour to find a complete expression for all mental acts in phj'sical terms is, to say the least, premature, and scarcely warrantable in our present state of knowledge. This leads its to the question. Has the nervous process of a simple reflex action a concomitant psychical process which corresponds to it? When we consider the plantar reflex, which is manifested even though psj^chical life is supposed to be non- existent, we are able to ans^^'er in the negative. The essential anatomical elements involved by the processes of reflex action are known to us, but the nature of the psychical process, or the extent of its concomitance with the physical process, is un- known. Ziehen says our consciousness, Avhich is alone able to decide the question, negatives the idea of such a correspondence. If our foot is but pricked unawares, it is only after the move- ]nent has been executed that we become aware of what has taken |>lace by a resultant sensation — the sensation of motion. The fitness of reflex action has been given as an argument to support the theory that there is a psychical concomitance with the physical process. In every reflex act we are forced to believe that the plwsical process is not confined to a sinarle afferent or efferent nerve or Ljanfrlion-cell. On the contrary, many are affected ; and if we are to explain the correspondence of a psychical event, we miist establish a corre- spondence not of one psycliical event with one physical process, but with many ph3'sical processes. These physical processes may lead to one resiilt — namely, the motor effect — and in the lower forms of reflex action the result tends to remain the same, no matter how the sensible stimulus may change ; but the con- REFLEX ACTIOX. 47 .^ciotisness of the excitation, or of its resulting effect (motion), ninst of necessity be, not the correspondence with one physical process, but with many. The lower forms of motor reaction do not seem to depend entirely npon the character of the stimuli. There is. however, a general fitness in their reaction, and it is npon thic fitness or unfitness of our reflex mechanism that our survival, as \physical organisms, in great part, depends. The argument triat this fitness implies a psychical correlate— i.e., that lower reflex acts which are fitting demonstrate their psychical nature — is of great importance as bearing upon the evolution of the mind in animals and man. Nerve-cells are believed to have the power of diminishing or intensifjdng the nerve-energy entering them. Thus the sensory stimulus Tuay become more complicated in its course of transmission. In the higher form of reflex action — in which co-ordination is evidenced — the concomitance of a psychical process has been assumed. The nature of this complicated motor reaction has given rise to much discxission and difference of opinion. Ziehen believes we have no ground whatever for assiTuiing that these higher or more complicated reflex acts are accompanied by psychical processes. Those motor reactions, however, which are not the invariable result of a definite stimulus, but are the modified result of new intercurrent stimuli, may be called (iidomatic acts or reactions, using the term automatic in its more restricted sense, and not including the so-called automatic rhythmical movements which are the result of internal stimuli. The instance given us of the pianist who executes an often- practised piece of music while his thoughts are wandering elsewhere, is of great significance, and the explanation is, that the visual image of the notes and the sensations of touch, imparted b}^ contact with the keys, act without interrup- tion upon the execution of the movements of the fingers. In an example of this kind the transmissions of the excitations n\a,j be explained as occurring along the lines of least resist- ance — along fixed paths, or so-called paths of conduction. Further, we maj^ conceive the occurrence of structural modifi- cations in these paths of conduction with the constant execution of definite functions ; but how are we to explain a still higher form of reaction, in which an individual is able to extemporise 48 PHYSIOLOGY OF THE NERVE-CELL. and construct new comliinations whilst his mind is engaged elsewhere, or, at the most, is only dimly conscious of the working of his reflex mechanism ? Such instances are not uncommon, and the musician ma}- possess a reflex mechanism of such exquisite sensibility that its constructive effects may be wrought without any obvious psychical correlate. An analysis of this phenomenon, however, is permissible, and we shall see that, in reality, this constructive power is an advanced develop- ment of the general fitness of reflex action |i?((s intercurrent stimuli. As in the former instance, the pianist's fingers, in spite of his absence of mind, glide over the notes in proper succession, and his movements tend to act in lines of least resistance. No effort of memory is involved in a psychical sense. Co-ordinative actions, which have been acquired for- merl}', now succeed each other in a relatively new order or sequence. Experience has taught the fingers how to avoid consecutive fifths and octaves. Relative progressions and in- tervals are treated A\ith an equal amount of accuracy. The hands approximate to. and diverge from, each other, and so accurate is their judgment of distance, that, taking their clue from one another, the fingers fall upon their proper notes without arousing the consciousness. To the young musician, such a mechanism is almost incom- prehensible, and were he to attempt to illustrate this by his own efforts, he would find, firstl}-, a failure in his co-ordinative move- ments — his fingers would be slow to adapt themselves to the necessary intervals, through insuflicient practice or ineptitiide ; secondly, sensations of resistance would be experienced, with an immediate stimulation or arousal of consciousness; and, thirdly, the results of long training in resolving discords, in weaving suc- cessions of notes or chords into rhythmical form ^^•ould be Avant- ing. Such considerations as these lead us to agree with Ziehen, tliat intercurrent stiniTili may so modify and, so to speak, im- prove upon the fitness of our reflex acts, that some of the highest and most complicated of our actions may be termed automatic, inasmuch as they may be performed without the concomitance of conscious phenomena. The " response movements" of Goltz also 1)ear out the same view, in that they are adapted to a definite ])urpose, and are able to overcome opposing obstacles. Ziehen FUNCTIONS OF NERVES. 49 claims that the first automatic movements to be met with in the animal series have been developed from reflex action through the agency of " natural selection." He believes that originally the amphibians which regularly avoided an obstacle suddenly placed in their way, thereby modifying their locomotor course, were just as numerous as those which did not. In the struggle for existence, however, the former had a decided advantage, for mechanisms situated below the cortex relieved the cerebrum of work, and other deeper nervous centres fittingly performed its functions. This fitting pecu- liarity was inherited, and constantly bred b}^ transmission, while those animals which were less favourably constituted gradually died out. The Functions of Nerves. — Our knowledge of the functions of nerves is no more advanced than that of nerve- cells. The various functions of nerve-fibres have been classified more or less according to the different effects produced by the conduction of nervous impulses along them. Thus we have the following classes : — (jt) nerves of motion controlling the muscular apparatus, whether of smooth or of striated muscular fibres ; (h) nerves of inhibition ; (c) nerves of secretion ; (d) trophic nerves, or nerves which have a direct influence upon nutrition ; (e) centripetal nerves that have no sensory functions ; and (/) sensory nerves, or those the excitation of which may result in conscious sensation.* With results so different as those seen in the above classes, we naturally ask ourselves ■whether those differences are due to variations in the modes of transmission of the impulse, or is the cause to be sought in the origin of the nerve-commotion ? For the present we are qiiite unable to satisfy ourselves in this respect, since our knowledge of the nature of the impulse transmitted has been shown to be so extremely limited. Ladd says, " Just as the same electric current ma}" pass along the same kind of wire, and write a message, or ring a bell, or move the legs of a frog ; just so, the irritation of certain fibres of the pneumogastric nerve resiilts in controlling the motion of the heart ; the irritation of other nerves seems to ha^'e no immediate metabolic effect in directing the secretory * Hermann, " Hanb. d. Physiol." II., i., p. 200 ff. 50 PHYSIOLOGY OF THE XERVE-CELL. processes : that of still others profoundly modifies the nutrition of the portions of the body to which they are distributed."' A more convenient classification of the nerve function of conduction is that of afferent and efferent, according as the nerves in question serve as conductors of nerve-^impulses inward toward, or outward from the nerve-centres. Some writers have supported the view that afferent and efferent nerves have the same specific mode of neural action ; whilst others believe that their respective molecular processes are essentially different. Our knowledge as yet. however, will not warrant us in giving credence to either of these views. We assume that impulses are propagated somehow along a nerve-fibre : we assume that such impulses may undergo variations, or even in the case of sensory nerves be transmitted backwards ; and we deem it possible that the transmission of impulses is attended with chemical change : but beyond this we must confess to being in a state of complete ignorance. The nature of a nerve-impulse is assumed to be that of waves of molecular vibration or of chemical action, or of the two in combination. Schiifer holds, that there is absohiteh no evi- dence of the first supposition, although the fact still remains that there is some evidence of chemical action. Upon the views of d'Arsonval — that the electrical phenomena of active muscle and nerve are produced by variations of surface-tension passing in a wave-like manner along the fibres — Schafer con- jectures that such waves of pressure, or surface-tension change, might possibly originate in consequence of the rhythmical contraction of the nerve-cell, or of smj of its processes. In illustration of this view Schafer says, "When a fibre of the pja'amidal tract is excited, the nerve- impulses which are generated in that fibre, and which are pro- bably of the same rate as the excitation, pass down to the grey matter of the spinal cord, and are there converted into nerve- impulses, which may have a very much less freciuent rhythm. This can only, so far as appears, take place at the adjunction of the terminations of the pyramidal-tract fibres with the motor nerve-cells : and it would appear that the motor nerve-cell is stimulated by the nerve-impulses which are conveyed along the fibre of the pyramidal tract, but that it responds to that action with a very miich slower rhythm than that of the assumed excitation ; for the excitation may be as rapid as 100 per second, or more ; but pro\ided it is not too FUNCTIONS OF NERVES. 51 intense, the impulses which pass along the motor fibres are only at the rate, as shown by the response of the muscle, of about 10 per second. The same thing is seen when the muscles are made to contract by a reflex excitation of the skin. Such an excitation may be very rapid or it may even be continuous. This rapid or continuous excitation of the fikin produces in the sensory fibre nerve-impulses, which may be assumed to be at least as rapid as the excitation itself, and these are ■conveyed to the grey matter of the lower nerve-centres, and are converted into nerve-impulses of a relatively slow rhythm, as shown by the rhythm of the reflex muscular response. This transformation may be assumed to occur either in the motor projection-cell, or in an inter- mediary cell, if any such intervene between the afferent fibre and the motor-cell, and the slow rhythm of the epileptiform convulsions which follow strong electrical excitation of the cerebral corteS;, and which certainly originate in the cells of the cortex, furnishes another well- marked instance of rhythmic production of nerve-impulses by nerve- cells." When we considered the anatoni}^ of the nerve-cell and the ramification of its processes we said, that there was no direct continuity between the nerve-cells, except through the con- tiguity of those ramified processes. Schafer has shown that, as a consequence, there is always a partial block to the passage of nerve-impulses at the conjunction of one cell with another, and he regards the period of time lost at this junction as representing the period of latent excitation of the nerve-cell. For an account of what probably happens at this point we cannot do better than again quote his own words : — " The nerve-fibre to which the excitation is applied carries nerve- impulses, which become spread out in the fine arborescence, which forms the termination of that fibre and which enwraps the motor-cell. From this cell nerve-impulses start which are not necessarily of the same rate as those which have reached the terminal arborescence just mentioned, and these new nervous impulses pass down toAvards the muscle and cause its contraction. It is clear that a change occurs at the adjunction of the arborescence within the cell-body. A change in rhythm certainly occm's,* and this renders it extremely probable that the nerve-impulses which are passing off from the spinal cord are entirely new impulses. If so, we may look upon this cell as having been freshly stimulated by the impulses which have passed along the fibre of the pyramidal tract. We may briefly consider in what manner it can be thus stimulated. Since there is no evidence that the fibrils of the arborescence anywhere touch the cell-body or its processes, we must assume that a space intervenes everywhere between the two, * " Journal of Physiology," 1886, vol. vii. 52 PHYSI0L0C4Y OF THE NERVE-CELL. A^ery narrow indeed, but still a space which cannot readily, if at all, be traversed by nerve-impulses. It is possible to suppose that the nerve- impulses reach the pericellular arborescence, and produce by mere induction new nervous impulses within the cell around which they play. But we have no evidence that such nerve-induction is possible. It is also open to us to suppose that the electrical change (action current), which accompanies the passage of the nerve-impulses to the arbores- cence, may itself be the excitant of the nerve-cell, and that the nerve- cell may respond to this excitation by a rhythmic chemical action, possibly molecular vibration, or perhaps a combination of two of these. At all events, it is probable that a new process is started within the nerve-cell. This does not necessarily follow from the fact that there is time lost at the adjunction, for a partial block to the passage of nerve- impulses and a resultant loss of time may be produced merely by mechanical means ; but the change of rhythm renders it extremely probable." The function of conductiviti/ of nervous imindses varies con- siderably under certain modifying conditions. The velocity of transmission of an impulse along a human motor-nerve is estimated by Helmholtz and Baxt to be 100 to 120 feet per second. In visceral nerves it is somewhat less (26 feet, Chauveau). Both elevation and lowering of the temperature lessen it. Anelectrotonus also diminishes, while cathelectro- tonus increases it. (Rutherford and Wundt). Negative variation in nerve is readily observed if a nerve ])e placed with its transverse section on one non-polarisable elec- trode, and its longitudinal surface on the other ; then, b}^ stimu- lating it electricall}^ chemically, or mechanically, the nerve- current is found to be diminished (du Bois-Reymond). Accord- ing to Bernstein, this negative variation is propagated towards both ends of a nerve, and is composed of very rapid, successive, periodic interruptions of the original current. The amount of the negative variation depends upon the extent of the primary deflection, the degree of nervous excitability, and on the strength of the stimulus employed.* Head found that it increased with tlu^ duration and strength of the stimulation, and with the drying of the nerve. The velocity with which negative varia- tion is propagated, as estimated by means of the differential rheotome, is a subject of great interest, but its further con- sideration must be for the present deferred. * Landois and Stirling, p. 559. INTERCELLULAR CONNECTIONS. 53 Do nerve-impulses pass backwards? It has been demon- strated by Gotcli and Horsley* that impulses do pass down afferent or sensory paths, but no matter how strong the stimulus employed, they do not pass up the efferent or motor- paths. Schafer offers an explanation of this in the anatomical arrangement of the terminations of the pyramidal tract fibres around the motor-cells, as compared ^\dth the mode of central termination of the sensory fibres within the grey matter. Such an arrangement, he conceives, may allow of the excitation of new nerve-impulses within the body of the motor-cell by an electrical discharge from the fine brush of pericellular fibrils which envelopes the body of the motor-cell; whilst the electrical change which accompanies nerve-impulses up the motor-fibre, when this is artificially stimulated, may be so diffused throughout the cell-body of the motor-cell, as to fail to stimulate and set up nerve-impulses in the pericellular ramification of fibrils, which represents the ending of the fibre of the pyramidal tract. The most important fact which has been pointed out of late, is that cells and fibres may functionate by contact only. The observations of Golgi, Ramon y Cajal, and Kolliker seem to demonstrate that direct continuity of structure is not essential for the propagation of motor, sensory, and reflex excitations. Kolliker t has demonstrated the truth of this in the cases of sensory root-fibres, which end free in the grey matter of the cord and medulla, the terminations of lateral branches of the nerve-processes of many of the cells of the grey matter, and also the terminations of the longitudinal fibres and collaterals of the anterior and lateral pyramidal tracts in the grey matter of the anterior horns. Intercellular Connections. — Ramon y Cajal X holds the view, that not only may the protoplasmic prolongations of the nerve-cells possess nutritive functions, but. also, they may, as well as the body of the cell itself, serve as conductors of nervous currents between neighbouring cells and elements at a distance. From the minute study of the histological appear- ances of the connections of the olfactory nerve-fibres, and those * "Phil. Trans.," 1891, vol. 182, B. + " Anat. Anzeiger," 1891. X " Croonian Lecture," Roy. Soc, March 8, 1894. 54 PHYSIOLOGY OF THE NERVE-CELL. of the visual fibres and of the retinal cells, he drew the conclu- sion, that not only do the protoplasmic expansions act as con- ductors, but also that the nervous current is inward tov\'ard the cell in these expansions, and outwards from the cell in the axis-cylinder. The nerve-cell has, in the dendritic expansion and the cell-body, an apparatus for the reception of currents, an apparatus for transmission in the prolongation of the axis- cylinder, and an apparatus for repartition or distribution in the terminal nervous ramifications. From an analysis of the quantitative and cpialitative difference which cerebral action presents among different animals and in the same animal species, Cajal regards the morphology of the pja^amidal cell as but one of the anatomical conditions of thought. But he does not believe that this special morphology will ever suffice to explain the enormous differences which exist, from a functional point of view, between the pja-amidal cell of a rabbit and that of a man, any more than between the pyramidal cell of the cerebral cortex and the stellate-cells of the cord or the great sympathetic. From the fact that the nerve-elements lose their power of proliferating after the embryonic period, an increase in the number of cells is not to be looked for as an essential feature in the improvement of organisation of the brain. On the other hand, it is probable that, in those regions which are most exercised, mental activity involves a greater develop- ment of the protoplasmic apparatus, and of the system of collateral nervous paths. It is in this way, says Ramon y Cajal, that associations already in existence between certain groups of cells would be notably reinforced by means of the miiltiplication of the minute terminal liranches of the proto- plasmic expansions, and of the collateral nervous paths. Further, absolutel}" new intercellular connections might be established by the formation of new collateral connections and protoplasmic expansions. The anatomico-physiological hypo- thesis, which bases intellect upon the richness of the cellular association, is open to an objection, which, however, this author fully recognises. How can the volume of the brain be maintained unaltered if there he a multiplication, and even a new formation of the terminal branches of the protoplasmic appendices, and of the collateral ner\'ous connection ? In reply INTERCELLULAR CONXECTIOXS. 55 to this objection, he states there is nothing to prevent our sup- posing either a correlative diminution of the cell bodies, or a proportional shrinking of those parts of the brain whose functions are not directly related to the exercise of the intelligence. We nia}^ thus explain family talent by supposing an hereditary transmission to the immediate or, by atavism, to the more dis- tant descendants of this superior organisation of the connections of the pja-amidal cells. In the case of those men in whom talent is coincident with a brain of small size, the nerve-cells ^\'ould be less numerous, or, perhaps, simply smaller; whereas, on the other hand, they would present a very complicated sj'^stem of protoplasmic nei'vous associations. The excessively large brain, on the other hand, so often associated with defective intelligence, or even with imbecility, would contain a greater number of cells, but the connections between them M-ould be very imperfect. As compared ^ith the theory of netAvorks, Ca,]al believes that the theory of the free branching of cellular expan- sions, capable of growth, is not only more probable but also more encouraging. " A continuous network," he says, " pre- established — -a sort of fixed telegraphic grillwork into which it Avould not be possible to introduce either new stations or new lines — it is a thing so rigid, so immutable, so unmodifial3le. that it does violence to the feeling which we all have, that the organ of thought is, within certain limits, plastic and susceptible of being improved, especially during the period of its development, by well-directed ' mental gymnastics.' " His comparison of the cerebral cortex to a garden containing innumerable trees (the pyramidal cells), which, in response to intelligent cultivation, can increase the number of their branches, strike their roots over a wider area, and produce ever more varied and more exquisite flowers and fruits, is open to criticism ; and we shall see that mere quantitative variations in cerebral structures are not, in reality, sufficient to explain qualitative variations in mental events. 56 CHAPTEE II. Chemical Phoperties of Nerve-substance. Specific Gravity — Percentage of Water — Albumin — Potash Albumin — Nuclein — Neuro-Keratin — Cholesterin — Cerebrin (Ilomocerebrin Encephalin) — Lecithin — Protagon. Vascular Supply of the Brain. Basal Arterial System — Anterior Cerebral Arteries — Middle Cerebral Arteries — Posterior Cerebral Arteries — Arterioles of the Cortex. Lymphatic System of the Brain. Regulation of Cerebral Pressure — Lymph-Cisterns — Perivascular Channels — Cerebro-Spinal Fluid — Pacchionian Granulations — Subarachnoid Space — Venous Circulation — Quantitative Rela- tions between Blood and Cerebro-Spinal Fluid. Brain-Movements. Pulsatile — Respiratory — Vascular — Nutrition of Nerve-elements — Functional Ilypersemias — Vaso-motor Centres — Influence of the Sympathetic. CHEMICAL PROPERTIES OF NERVE-SUBSTANCE. When we begin to study the chemical and mechanical pro- perties of nervous substance we find that the facts with which we have to deal are comparatively few in number, and their import uncertain. This is not to be wondered at when we remember that the nervons tissues are formed by highly complex and unstable compounds. Attempts have been made to estimate the chemical nature of the white and the grey nervous matter respectively, and they have been found to SPECIFIC GRAVITY. 57 differ not only in cliemical constitution bnt also in specific gravity. It must be remembered, however, that it is difficult to make an absolute distinction between the white and the grey substance, and more especially is this the case in investigations where facts can be obtained only by an examination of the entire masses of the brain. Meynert recommends his method of dissectinsf out the brain-trunk and cerebellum from the hemispheres as peculiarly adapted to such investigations, but no one seems to have adopted his suggestions, and our knowledge on this head is exceedingly fragmentary. Danilewski attempted to estimate the elements of the grey and the white substance by means of a comparison of the differences in their specific gravity. He found that the sp. gr. of the grey substance varied between 1'029 and 1*038, and that of the white substance between r039 and 1"043. In man, he found the relative proportions of both substances to be 37*7 to 39 per cent, of grey substance, and 61 to 62*3 per cent, of white substance ; while in the dog, the grey and the white substance were present in equal proportions. Bastian, W. Krause, and L. Fischer estimated the mean sp. gr. of the grey matter at about 1-031, of the white at 1-036— 1-040. * The explanation of this difference in weight is attributed to the relative amount of water and of solids which they contain. Gamgee f has given a tabular statement of Weisbach's investigations as to the amount of water entering into the composition of the different parts of the central nervous system. From this table the largest percentage of water is found in the grey substance of the brain (83 per cent, approximately). The cerebellum comes next with about 78*5 per cent. ; then the medulla oblongata, 74-5 ; pons Varolii, 73-5 ; and the white substance of the brain about 70 per cent. The cortex contains 86 per cent. ; the medullar)^ substance of the hemisphere 70 per cent. ; the oblongata 74 per cent. ; sympathetic 64 per cent. Bernhardt found a smaller proportion of water in the cervical region of the cord (73-05 per cent.) than in the lumbar (7604). Another fact ascer- tained from the results of Weisbach's observations is, that in man between the age of twenty and thirty there is a relatively * Ladd, " Physiol. Psych.," p. 22. t "Physiological Chemistry of the Animal Body," i. p. 445, London, 1880. 58 CHEMICAL PROPERTIES OF XERVE-SUBSTANCE. higher percentage of water than between the age of thirty to fifty ; and, further, that between the age of seventy and ninety- four there is a higher percentage than at either of the former ages. Observations are much wanted upon these points, and it is of importance to us to know under what conditions u e are to expect an increase in the watery constituents, both in the normal and the morbid brain. At the present time our know- ledge of the relative proportions of such an increase in general paralysis of the insane, and other progressive brain diseases, is, so far as I am aware, absolutely nil. Mejniert regards the preponderance of grey substance in animals compared with the grey substance in man, as dependent upon the excess of amorphous connective tissue in the former. In man this sub- stance is regarded as albuminous in character ; hence Boll considers it allied to connective tissue, which, he claims, con- tains remnants of albumin derived from formative cells, and only differing from other connective tissue in the possession of a greater quantity of albumin. Alhumin is found both in the axis-cjdinder and in the substance of the ganglionic cells. Some of this proteid substance was formerly regarded as myosin, and presented characters not unlike those of this compound. We no^^' know, however, from the experiments of Petrowsky, that this substance is insoluble in a 10 per cent, solution of sodium chloride. The dilute solution of this salt extracts a proteid from nervous matter, which is, however, precipitated by the addition of much water, and by a concentrated solution of the salt. Fotash alhumin and a r/lobidin-like substance are also present.* Both Kiihne and Ewald found, that if grey nervous matter was subjected to artificial digestion, by trypsin — the pan- creas ferment — two substances remained undigested, wiiclein and neuro-lxeraiin. The latter being obtained by treating the residue with caustic potash. The occurrence of nuclein in the grey matter is said to impl}' the presence of phosphorus in the ganglion-cells and axis-cylinders. But whether this substance (nuclein) is actually l)resent in the brain at all is a matter of doubt. Yon Jaksch and Drechsel believe that it does occur, but its existence has * Landois and Stirling, p. 531. NLX'LEIN AND XEURO-KERATIN. 59 been denied by Worm-Miiller and Gamgee. The formula of this substance is given as CggH^gNpPgOgg. Jaksch found an excess of nuclein in the grey substance as compared with the white. He did not, however, thoroughly isolate the grey sub- stance. Geoghegan also found it in the proportion of 1'4 to ever}" 1,000 parts of the entire cerebral mass. From the experiments of Mej'er and Cornwinder — who proved that in plants the quantity of phosphorus increased in direct pro- portion to the quantitj" of nitrogen ; and the researches of Bischoff, A^dio found phosphoric acid in a definite proportion to the quantity of nitrogen in the urine of starviiig animals, ^^-hereas, the quantitj^ of phosphorus taken in Avas greater than that in the excretions if the animal was properly fed — A^oigt infers that the albuminates and phosphates unite, so that the fundamental connective tissue, as well as the nerve-cells in the grey substance of the brain, must be classified with those substances which contain phosphorus. In the chemical com- position of the brain the element of phosphorus of the grey substance constitutes an important factor. Meynert, relying upon the observations of Schlossberger, Bibra, Pollak, and Jaksch, estimates that a fresh brain contains 0'49 per cent, of phosphoric acid in its gre}^ substance, and 0*89 per cent, in its white substance. He says we are not A\'arranted, however, in concluding that the nervous system contains an absolutely larger quantit}^ of phosphorus. The quantity of phosphorus in the nervous system cannot be gauged by the amount of phos- phorus in the excretions ; for, as Voigt has determined, the entire nervous system of man contains but 12 grains' of phos- phoric acid as compared with 130 grains in the muscles, and 1"800 grains in the bones; and, besides, we know, ever since Chossat's starvation exjieriments were published, that during starvation the nervous system sho-ws no appreciable loss of weight. Neuro-keratin occurs in the corneous sheath of nerve-fibres. It is also found in the grey matter of the nerve-centres, and in the retinal epithelial cells and pigment cells of the choroid ; but not in the non-medullated nerve-fibres. It is a body containing much sulphur, and is closely allied to keratin. It is soluble only in a hot concentrated solution of caustic 60 CHEMICAL PROPEKTIES OF XERVE-SUBSTANCE. potash and sulphuric acid, and amounts to but 15 or 20 per cent, of the dried residue of the alcoholic or ethereal extract of the brain. If the fatty matters of the medullary sheath are extracted with boiling alcohol and ether, this highly retractile substance is left as an irregular network. Gltolesterin (CggH^^O + H^O) is regarded as a monad alcohol which occurs in a free state, especially in white nervous sub- stance. It is non-nitrogenous, taking the form of fine needles or rhombic tables when separated from its solution in ether or alcohol. Hoppe-Seyler says that this body is probably merely suspended, and not dissolved, in protoplasm ; that it is common to all living vegetable and animal cells, taking no important part, however, in the development of the cells. It is uncertain whether it is, as maintained by Hoppe-Seyler, a product of decomposition resulting from the organic changes during cell life. Petrowski states that lecithin and cholesterin originate from the cells of the grey substance and not from the white substance mixed with it. According to Drechsel, the terms lecithin, cholesterin, and cerehrin designate mixtures only ; of which lecithin applies to the phosphorised substance which has been dissolved by ether and alcohol ; cholesterin to the ethereal extract which remains after removing the lecithin ; and cerebrin to the substances which form crystals in hot alcohol, but are insoluble in cold alcohol (v. Meynert). Cerehrin (Ceg^gH-^j^^No^g. Parous) is a white powder com- posed of spherical granules soluble in hot alcohol and ether, but insoluble in cold water. It is prepared by rubbing up the brain into a thin fluid with baryta water. The separated coagulum is then separated with boiling alcohol (Miiller). Parens gave the name of honiocerehriii to a substance which he separated from cerebrin, this substance being slightly more soluble in alcohol than cerebrin. He also found a '' clyster-like" body, sokdjle in hot water, which he named encephaUn. Lecithin (C^^\i.c^\^0^. Diakanow) occurs as a phosphorised organic compound in the matter of the brain, and from its decomposition products we obtain glycero-phosphoric acid PROTAGON. 61 and oleophosphoric acid. Lecithin is a salt of the base neitrin.^^ Ganigee believes that lecithin is only one of a group of bodies which possess a higher percentage of phosphorus than protagon. It is soluble in water and alcohol, and has been formed sj^ntheticalh' from glycol and trimethylamin. Proiafjon {G^^f^.24:^^'P-2'>P) ^^ regarded b}- its discoverer, Liebreich, to be the chief constituent of the brain. It con- tains N and P, and resembles cerebrin. This substance is considered by some observers to be the only well-established phosphorised proximate principle of the brain. Ladd believes it to be the best representative that chemistry can as yet present, of a scientific result upon which to base any attempt to point out definite relations between psj^chical activities and the chemical constitution of those complex phosphorised bodies which exist in the centi^al nervous mechanism, and he regards it as highly probable that protagon is not a com- pound or mixture of cerebrin and lecithin. The contro- versy as to whether protagon is a definite ultimate chemical principle, or a mixture of lecithin and cerebrin, has attracted a considerable amount of attention. The former view has been upheld h\ Kiihne, Blankendorf, and Gam gee, whilst Diakanow, Hoppe-Seyler, and Thudicum have advocated the latter. From a phj^siological and psychological point of view con- siderable importance is attached to the discovery of the com- position of these highly complex phosphorised substances. More recently Drechsel has discredited the view that pro- tagon is merely a mixture, b}^ pointing out that the atomic Aveights of lecithin and cerebrin do not suffice to make a mixture of the nature of protagon, and that a third substance would have to be shown to exist containing more nitrogen and less carbon. The power the medullary siabstance of the brain possesses of reducing osmic acid, and turning a black colour, is regarded by Meynert as an additional reason for the exist- ence of a body like protagon. He recognises, however, that these peculiar qualities are common, also, to the myelin forms of protagon resulting from prolonged contact of protagon with * Landois and Stirling, p. 331. 62 CHEMICAL PROPERTIES OF NERVE-SUBSTANCE. water. Diakanow contended, although apparently without proof, that protagon contained no phosphorus at all. Blanken- dorf, Gamgee, and Drechsel found that the percentage of phosphorus was constant in protagon, although it had been re-crystallised four or five times. The hygroscopical characters of lecithin and cerebrin have led ]\Ieynert to believe, that though lecithin and cerebrin (the latter a substance without phos- phorus) exhibit the starch-like properties and myelin-like forms, there is not sufficient ground to doubt the formation of these siibstances from the protagon of the brain, but that their marked hygroscopical properties stand in broad contrast to the lack of such qualities in protagon. '■ If protagon "N^-ere a mixture of cerebrin and lecithin it would be difficult to con- ceive how a non-hygroscopical body could result from the union of two hygroscopical bodies. It would be more natural to suppose that the hygroscopical properties were the result of the more elaborate methods by which cerebrin and lecithin are recognised as secondary brain constituents, while protagon, a primary brain substance, is obtained in advance of these." From these brief considerations the student must not for one moment imagine that he possesses anything like an adequate knowledge of the chemical constitution of nervous ■substance. Thudicum* states, that a quantitative analysis of the brain involves at least three hundred cpTantitative deter- minations of definite bodies or compounds. Each of the four ■divisions of the brain, and each of the two varieties of tissue — the white and the grey — would thiis require at least about fifty quantations for chemical characterisation. Our account must necessarily be limited, and we are compelled to refer the student to the comprehensive article by Thudicum, in "Tuke's Dictionary,"' for details of the group of inorganic principles which have been isolated from the brain; and we hope, ^^'ith this author, that more attention may be given to this subject by those who make psychological medicine their especial gtudy. * "Tuke's Diet. Psych. Jled.,'' vol. i. p. 15:?. VASCULAR SUPPLY OF THE BRAIN. 63 VASCULAR SUPPLY OF THE BRAIN. Our knowledge in reference to the vascular supply of the brain has been rendered more accurate owing to the inde- pendent labours of Heubner and Duret. The entire arterial supply of the brain has been divided into two systems- — viz., a Jiasal and a cortical arterial system. Here, we shall have to deal more particularly with the latter, for a full description of the source and mode of arrangement of the basal system would be beyond our object. From the hctsal arterial sijstem, as represented by the circle of Willis, numerous small branches pass off nearly at right angles, and enter the ganglia near the base of the brain. These are called " terminal" or " end " arteries, because they do not anastomose with one another ; nor do they anastomose with the vessels of the cortical arterial system. The anterior cerebral and the middle cerebral are the main arteries of the forebrain. The former supplies the superior frontal and anterior two-thirds of the middle frontal convolutions, and the upper extremity of the ascending frontal. It has four cortical branches. The first supplies the two internal orbital convolutions ; the second is distributed, to the anterior extremity of the marginal convolu- tions, to the superior, and to the anterior portion of the middle i'rontal convolutions on the outer surface ; the third passes to the inner surface of the hemisphere as far as the calloso- marginal fissure ; whilst the fourth goes to the quadrate lobule, and also gives off a branch to the corpus callosum. On the median surface, the corpus callosum, and the entire region from the frontal apex to the sulcus occipitalis, receive their blood-supply from the anterior, median, and posterior internal branches of the anterior cerebral arteries. The middle cerebral. in addition to the numerous small vessels which pass through the foramina of the anterior perforated space to the corpus striatum, the two grey nuclei and lenticular nucleus, and to the posterior part of the nucleiTS caudatus, gives off from its main trunk, as it reaches the island of Reil, several branches. These branches, as given by Charcot, are as follows : — (1) tjie 64 VASCULAR SUPPLY OF THE BRAIN. external frontal, supplying the inferior frontal convolution; (2) the ascending frontal to the region of the anterior cerebral convolution ; (3) the ascending parietal to the posterior central convolution and the superior parietal lobule ; (4) the parietal to the parietal convolutions ; and (5) temporal arteries, which ramify over the first and second temporal convolutions. The ijosteriov cerehral artery gives off numerous branches in the posterior perforated spot, and others as it passes round the crus, both of which sets pass into the thalami optici, crura cerebri, and corpora quadrigemina. It has three cortical branches, one to the anterior part of the uncinate gyrus and its immediate vicinity ; one to the posterior part of the uncinate gyrus, and the lower part of the temporo- sphenoidal lobe ; and a third to the occipital lobe on its outer and inner sui-faces.* From the distribution of the anterior, middle, and posterior cerebral arteries, we see that the}' determine the l)lood-supply to certain regions. Each main arteiy gives off secondary and tertiar}^ branches. These tertiary branches, in their turn, give off numerous fine fila- ments, which, according to Duret. do not anastomose with one another, although a communication may take place, to a certain extent, bet^\'een the branches of contiguous areas. Opinions differ considerably upon this question of anastomosis between the vessels of the cortical system. Heubner, basing his opinion upon the result of his injections, believes that there is a free anastomosis between the main vessels and also between the secondary branches of the vessels of the cortex, the anas- tomosis being effected through vessels not less than a millimetre in diameter. He does not believe that col- lateral compensation is effected solely through the circle of Willis. In consequence of this view, objection is taken to the statement that an arterj^ supplies any definite region or convolution. In support of Heubner's view, we have the fact, admitted b_y Charcot, that in certain cases of arterial obstruction by embolism or thrombosis, there is an exemption from softening, * H. Duret, "Archives de I'liysiol.," 1874, and Heubner, " Centralblatt fiir die Med. AVissensch.," 1872. ARTERIOLES OF THE CORTEX. 65 which would point to the establishment of a collateral circulation. Duret contends that such anastomoses are absent or extremely rare, and he maintains that it is only through the terminal filaments of the branchlets that communications occur. Such communications, however, he believes, may vary in number in different individuals. Cohnheim also maintains that there are no anastomoses between the larger branches of trunk arteries, but that all the cerebral arteries more or less resemble true terminal or end arteries, in that they onh" communicate with other vessels through their ultimate capil- lar}^ loops. Meynert believes that the arteries supply definite nutritive .areas, and that the influence of the derivative net- work is not as powerful as Heubner would have it ; further, he regards, as of great importance in cerebral patholog}^, the fact that, as there is no derivative network beyond the circle of Willis, these arteries, because of their shortness, are under the more immediate influence of cardiac action, and are therefore more liable to rupture than the cortical arteries. Arterioles of the Cortex. — In his monograph on the structure of the cerebral cortex (1868) Meynert showed that the cortex was supplied with a large number of arterioles from the broad expansion of pia. All these arterioles were about the same size, and entered adjacent portions of brain tissue. Each one, moreover, represented, to a certain degree, an independent circulatory area. His observations led him to the belief that in a mass of tissues, supplied by a smaller number of larger arterial branches, it would be quite impossible for differences of arterial blood-suppl}^ to exist simultaneously in adjacent portions of that tissue. From this he inferred that partial functional liyperaBmia of separate cortical areas was readily permissible, and that the so-called cortical centres could be functionally hypersemic at a time when the other cortical centres were functionally at rest. The blood-supply to the brain would in this way be determined by the functional hypersemia of the areas which were in a state of activitJ^ In the pia mater we have, then, main arteries with their branches, branchlets, and fine filaments. From the branchlets and filaments a great number of minute arterial twigs pass at right 5 66 VASCULAR SUPPLY OF THE BRAIN. angles into the cortex. These are commonly known as nutrient arteries : they are very slender, and vary in length. The longer twigs pass through the grey matter into the white substance, where they approach the terminal twigs of the basal arterial system, but with which, however, they are said to have no communication. In their course they give off numerous fine offsets, wliich communicate with the capillary network of the shorter ultimate arterial twigs. These latter usually terminate in a capillary network within the grey matter itself. In cases of embolism or thrombosis, therefore, Fig. 6. Injected Cerf,b"ellum of Cat, showing Cortical Arrangement of Blood-Vessels A, inner granule layer ; B, layer of corpuscles of Purkinje ; C, external layer ; D, vessels of pia mater. not only does the grey matter of the cortex suffer, but also the subjacent white matter, the amount of destruction, of course, depending upon the size of the vessel obstructed, and the amount of communication existing between it and its neighbours. Meynert states that the larger branches of the arteries, on the surface of the brain, do not lie within the pia, but in the subarachnoidal spaces ; the smaller branches only entering the pia. The general relations between the blood-vessels of the brain and the membranes is, as we shall see, a question of importance, as bearing upon the mechanism of nutrition. Before entering, however, upon this question, we must con- STRUCTURE OF THE CEREBRAL ARTERIES. 67 sider some other anatomical and physiological conditions, which have a direct bearing upon the quantity and qnality of the cerebral blood-supply. ^..._ A Fig. 7. Short Nutrient Artery of Cortex Cerebri, showing Capillary Network. A, pia mater; B, white matter. Structure of the Cerebral Arteries.— The cerebral arteries have less muscular element than those of the body generally. In the larger arteries the tunica adventitia is directly continuous with the pia mater ; whilst, in the smaller vessels, this sheath becomes an extremely fine membranous investment, either structureless or faintly striated, and with nucleated connective-tissue corpuscles upon it. The nuclei of these corpuscles proliferate readily. In some conditions ampullar dilatations are prone to occur. These dilatations are regarded by Bevan Lewis as being due to separation of the adventitial sheath from the tunica media, and a space between the two coats is to be seen at all times in the angle formed b}- the bifurcation of the vessel. The vessels of the cortex lie in channels — the perivascular channels of His — which are continuous with the epicerebral space. Numerous delicate fibrillar processes, which arise from the stellate cells of the cortex, traverse this perivascular space, 68 VASCULAR SUPPLY OF THE BRAIX. and form connections with the arterial sheath (Bevan Lewis). The capillaries of the cortex are of extremeh* fine calibre (not over 4/i in diameter, and of less calibre than the red blood- corpuscles). Bevan Le^^'is says, however, that we must allow for possible shrinking of the vessel by emptjang its channel, as well as for the constricting effects of reagents, and that we can scarcely conclude that even these minute ramifications do not permit the passage of the red corpuscle. The same author makes the following observations upon the structure of the capillaries : — " The only constituents of the arterial tunics, which enter into the structure of the capillary, are the endothelial layer or intlma and the adventitial Investment. In fact, the transition from the smallest artery Blood-Vksskl of the Human Brain, showing several Neuroglia Fibre-Cells SURROUNDING IT AND FORMING A FELT-WORK (PERIVASCULAR SYSTEM). a. An eucircling cell ; p, perpendicular neurojilia fibre entering the sheath at right angles from a distant (cxtrinsif) cell (Golgi's method). — {Andriezen.) into tlie larger capillary is indicated by the disappearance of the muscular iibre-cell, and the continuation of the channel as an apparently homogeneous tubular membrane, with oval nuclei along its course, and here and there nucleated connective cells as the sole representative of the adventitial sheath. The intima, which is a direct continuation of the endothelial lining of the arteries, and by many believed to be the onli/ constituent of the capillary, resembles that lining in every STRUCTURE OF THE CEREBRAL ARTERIES. 69 particulav, save the number and form of its squam.ous cells. These are not only fewer, being often reduced to two in a transverse view of the vessel or its lumen ; but instead of being polygonal, are more often elongated into fusiform plates. " In the smaller capillaries the delicacy of the structure is such that it is at first often overlooked until its course is noticed, mapped out by short, narrow, spindle-shaped nuclei, arranged alternately at regular distances on the opposite sides of the vessel. In the same direction also will be found rounded nuclei, staining readily with aniline blue- FiG. 9. Structure of Large Vessel, SHinvixo Perivascular Felt-work of Neuroglia Fibres. Dense on the right side, less dense on the left side a, where it is distinctly separated from the blood-vessel by a space; )3, extrinsic cells (Human Brain, Golgi's Method). — {Andriczen, " lutemat. Monatsch. fiir Anat. u. Phys.," 1893, Bd. x., Heft, ii.) black, sometimes aggregated into groups or arranged in linear series at very irregular intervals along the vessel. These are the derivatives of the adventitial sheath, and are, therefore, always external to, and placed upon, the fusiform nuclei. They are often the best guide to the direction of the capillary loops around the nerve-cell." 70 THE LYMPHATIC SYSTEM OF THE BRAIN. THE LYMPHATIC SYSTEM. To the stud)' of the lymphatic system of the brain consider- able importance is attached, and our knowledge upon this difficult subject may be attributed chiefly to the labours of Obersteiner, Ke^^ Retzius, Schwalbe, Meynert, and Bevan Lewis. Obersteiner was the first to define the nature and con- nections of the lym}Dh-channels in the brain ; whilst Bevan Lewis is to be credited with having given us the latest and most advanced details as to the relationship of the cortical nerve- cells to these lymph-channels, both in health and disease. It will simplify the subject, if we diverge for a moment to consider the relationship of the cranium, with its rigid walls, to the brain. Regulation of Pressure of Cerebral Fluid. — Meynert believes that the skull regulates the pressure of the fluid within its cavity, and hence becomes an important factor in the nutri- tion of the brain.. He states that if the brain were surrounded merely by rigid cranial walls, a partial change in the distribution of arterial blood would be conceivable. A functional increase, however, would be possible onl}' upon one of two conditions — viz., a corresponding collateral arterial diminution, or a transfer of venous blood in the direction of the sinuses. For the first condition, he thought it would be difficult to explain an appropriate mechanism. A venoi;s transfer would be altogether too slow, and there could not be any continuous action, for the repulsion of the venous current, dependent upon the respirator)^ movements, would give rise to a frequently interrupted flow of venous blood in the brain. The cranial cavity is not entirely filled by the brain ; it includes, in addi- tion, a number of spaces filled with lymphatic fluid. The dura mater is separated from the arachnoid by a comparatively small space, which is lined by endothelium. This space communi- cates with the lymphatic glands of the neck, and with the sub- dural spaces which do not immediately surround the nerve- roots, but do so in common with tlie arachnoid, and are con- nected with the lymphatic spaces of peripheral nerves.* As an example, we have the communication between the auditory labyrinth and the subdural space through tjie spaces which * Meynert, " Psychiatry,'" p. 218. LYMPH-CISTERNS. 71 surround the auditory nerve. In the tissue of the dura itself there are also lymph-spaces which are connected with the subdural space. Lymph-Cisterns. — The explanation of the formation of the so-called " cisterns " is to be found in the relationship of the arachnoid membrane to the pia. They are connected by means of a network of threads and trabeculae of connective tissue, and at the base of the brain by means of perforated membranes. At the summit of the convolutions the threads of this network are narrower than over the sulci ; whilst, at the base of the brain where the subarachnoidal spaces are dilated, there may be no trabeculse. Meynert enumerates the following cisterns which belong to the surface of the cortex : — " The space of the fossa Sylvii, which is merely spanned by the arachnoid, and a space which separates it from the dorsal surface of the corpus callosum, which space extends on the basilar surface as far as the linea termmalis (of the central grey substance) situated beneath the corpus callosum. Farther back on the basilar surface we come upon the cysterna chiasmatis and the cystern«. intercruralis, the latter dividing again into a superficial and a deep reservoir. Fi'om the cysterna intercruralis and to the outer side wide subarachnoidal spaces extend across the crus cerebri to the corpoi'a quadrigemina — i.e., from the basilar surface to the dorsal surface of the trunk, the cysterna ambiens. Short trabeculae unite the subarachnoidal space just over the corpora quadrigemina to the surface of the latter. The most extensive sub- arachnoidal space on the dorsal side is the cysterna magna cerebello- medularis, extending from the dorsal surface of the oblongata to the cerebellum, on the superior surface of which exactly the same relations obtain as over the convolutions of the cerebrum. "Behind the corpora quadrigemina, the arachnoid of the cysterna ambiens ascends to the upper wall of the cysterna corporis callosi. The flexion of the cerebellum over the oblongata produces, furthermore, a fold in the pia on its way from the cerebellum to the oblongata, the two laminae of this fold giving rise to the tela choroidea of the fourth ventricle. The foramen Magendie leads through the pia from this ventricle into the subarachnoidal space of the spinal canal. In regard to the third ventricle, it is to be remarked that its membranous tela does not correspond to the superior wall of the primary cerebral vesicle, but that the only vestiges of this which remain are the epithelial cells of the plexus choroideus, at the lateral margin and on the inferior sux'face of the velum." In the brain-cortex all the vessels are inclosed within channels, known as the iierivascular channels of His. These 72 THE LYMPHATIC SYSTEM OF THE BRAIN. channels are noticeable in hardened sections, and most markedly so in cases of atrophy of the cortex. Bevan Lewis differs from several authors in that he believes they are not the lymph- channels proper, but simply channels in the brain-substance, without an endothelial lining, and having free communication with the epicerebral space. He says these channels appear to be eqiiivalent to an involution of the nahed surface of the brain, and yet the epithelial elements of the epicerebral surface are not continuous along this tubular canal, llieir appearance of being lined by endothelial cells is said to be due to the adventitial sheath of the blood-vessels, which becomes " closely appressed " to its limiting channel. The nerve-cell has around it a somewhat similar space, which Bevan Lewis has termed the pericellular sac, and he regards these as genuine sacs, and not mere artificial gaps in the brain-substance.* The peri- vascular channels and pericellular sacs communicate with the perivascidar lymph-spaces of the adventitia. The study of the lymph connective system is of great importance in cerebral pathology; but it is yet to be shown how the individual elements of this system undergo morbid changes and cause alterations in the movements of the lymph. Bevan Lewis has summarised his account as follo\A'S : — " The lymphatic system of the brain consists of — '* (1) A distensible lymphatic sheath, loosely applied around the arterioles and venules, containing numerous nucleated cells in its texture — the adventitial lymph-i^heath — the whole being included within a non-distensible channel of the brain-substance, devoid of endothelial lining — the perivascular channel of His. " (2) A continuation of the cellular elements of this sheath, loosely applied to the arterio-capillary plexuses, still contained within a peri- vascular channel, which now exhibit along the capillary loop sac-like dilatations — the pericellular sacs, within which the nerve-cell lies, surrounded by plasma. " (3) A system of plasmatic cells with numerous prolongations, which are always in intimate connection with the adventitial lymph-sheath, and which drain the areas between the vascular branches — tei"med the lymph connective elemetits. " Finally, if we take a comprehensive view of the whole system, the channelled vascular tracts, the saccular ampullae along the capillary tube, the canalicular-like formation of the lymph-connective elements, all * Bevan Lewis, "Mental Diseases," p. 823. PACCHIONIAN GRANULATIONS. 73 eiubedded in a homogeneous matrix of neuroglia, we cannot but be struck by the sponge-hke arrangement of the cortex, and the facihties so offered for the free circulation of plasma throughout its most intimate regions." Cerebro- Spinal Fluid. — The cerebro-spinal fluid in the brain is secreted by the epithelium of the choroid plexuses in the lateral, the third, and the fourth ventricles, and, possibly, from the general epithelial linings of these cavities. The fluid is transparent, and has a specific gravity of about 1010. The view that the lymph-cisterns act as a water cushion to minimise the shock to the brain and to compensate variations in blood- pressure, is supported by the fact that, in cases of spina bifida, the cerebro-spinal fluid can be readily driven from the spinal canal into the cranial cavity by pressure on the tumour, so that it may be assumed that a passage may be as readily effected in the reverse direction (Bruce).* Before entei'ing upon a descrip- tion of the various brain-movements, it would, perhaps, be well to consider briefly some points in i-egard to the Pacchionian granulations. Pacchionian Granulations. — Meynert loolcs upon these bodies as prolongations of the subarachnoidal spaces. They occur in the course of all sinuses, but more particularly along- side of the sinus longihidinalis. The cerebro-spinal fluid is removed from the subarachnoidal space by several channels. Much of it passes into the corresponding space round the spinal cord, and escapes outwards along the subarachnoidal sheath of the spinal nerves. The remainder passes along the corresponding sheaths of the cranial nerves, or is excreted by the Pacchionian bodies into the superior longitudinal sinus in the dura mater (Bruce). The subarachnoidal space is to be regarded as a true serous cavity, or lymph-space. Langer describes the sinuses, and the veins adjacent to them, as situated in the substance of the dura, and arranged in such a manner that the veins of the anterior portions of the hemispheres meet with the veins of the posterior lobes in the walls of the sinus longitudinalis, as though the former (veins) stood in the relation of rasa vasorum to the latter. * " Tuke"s Diet. Psych. Med.,"' p. 172. 74 THE LYMPHATIC SYSTEM OF THE BRAIN. Meynert has shown that a definite brain-pressure forces the serous fluid from the subarachnoidal space into the subdural spaces, whence, by a process of filtration, it empties into the veins and sinuses. " The posterior cerebral veins take a similar longitudinal course forward, between the layers of the dura, so that the cerebral veins empty into the sinus for a distance of only 2 cm., and about below the middle of the parietal vertex. The Pacchionian formations push forward into the cerebral veins as diverticula of the subarachnoidal spaces. The veins lie intradural, and the subarachnoidal sj^aces are shut off from the subdural space. "The subarachnoidal spaces communicate, moreover, with the lymph- channels of the peripheral nerves, which encircle the roots, as does the dura also. From these subarachnoidal s^jaces we can throw injecting fluid into the lymph-space surrounding the optic nerve, into the peri- lymphatic space of the labyrinth, and the lymj^hatic vessels of the nasal mucous membranes." The venous circulation within the cranium presents several peculiar features. The blood flows along the longi- tudinal sinus towards the occiput, and hence its course is opposed in direction to the blood issuing fi'om the cortical veins, which open into the sinus in a forward direction. Hence the fact, that the blood which enters the brain by ascending arteries reaches the sinuses by ascending veins, is made use of to explain the occurrence of thrombosis in these vessels — the explanation being, that here gravitation is opposed to the flow of blood. In this way, morbid processes affecting the scalp — such as erysipelas, caries, or carbuncle — may readily affect intra- cranial structures by means of the communication with intra- cranial veins — e.'/., those of the nose, the facial through the ophthalmic, the mastoid veins, and the veins of the diplooe. Cerebral anaemia is sometimes produced, owing to hydrostatic causes — e.g., if a person who has been in bed for a long time and whose blood is small in amount, be suddenly raised into the erect position. Such a condition is also not infrequently at- tended b}^ loss of consciousness. Liebermeister regards the thy- . roid gland as a collateral blood-reservoir, which empties its blood towards the head during such changes of the position of the body. duantitative Relation between Blood and Cerebro- spinal Fluid. — There is an intimate relation between the BRAIN-MOVEMEXTS. 75 amounts of cerebro-spinal fluid and blood within the cranial cavity. When more blood passes in. some cerebro-spinal fluid passes out, and vice versa. Formerly it was taught that, as the skull is a rigid box, and as the brain-substance and its fluids are practically incompressible, no variation in the amount of blood in the brain could be possible. This, however, is now proved to be erroneous. The average quantity of cerebro-spinal fluid within the cranium is about two ounces, and if it be suddenly with^ drawn, epilepsy or convulsions may be produced ; or, if it be rapidly increased in amount, coma may result. This fluid has also important mechanical functions, protecting delicate parts of the brain from injur}-, and by distributing vibratory impulses it insulates the nerve-roots. The presence of the cerebro-spinal fluid is, as pointed out by Donders, of great importance in regulating the pressure uniformly when brain- movements occur, so that every systolic and expiratory dilata- tion of the blood-vessels is concentrated upon those parts of the cerebral membrane which do not offer any resistance. These movements almost disappear when the fluid is absti-acted. The fovece (jlandulares, according to Langer and Trollard) are venous, cavernous spaces produced by the wearing away of the vitrea, and are to be found in drunkards, in the senile, and in the subjects of heart disease. They are not, says Meynert, direct impressions of the Pacchionian dilatations of the sub- arachnoidal spaces. Meyer regarded their life as compensatory, inasmuch as they dilate with anaemia and collapse when there is a full current of blood within the brain. The increase and diminution of the amount of blood and cerebro-spinal fluid within the cranial cavity, is a question of great importance as bearing upon the nutrition of the brain ; and it is by means of the orderly working of this mechanism that waste products are transferred from the circulation to the lymph-vessels. BRAIN-MOVEMENTS. The movements of the brain ai'e of three different kinds : — («) pulsaMle movements communicated from the pulsations of the large basal cerebral vessels ; (6) respiratory move- 76 BRAIN-MOVEMENTS. ments, so that the brain rises during respiration and falls during inspiration ; and (c) vascular elevation and depres- sions which alternate, and are due to periodic dilatation and contraction of the blood-vessels. This last is a peri- staltic arterial movement, regulated by the vaso-motor centre, and occurring from two to six times per minute (Meynert). These movements have been investigated chiefly over the fontanelles of children, and where the membranes have been exposed by trephining. Burckhardt's observations were made upon four patients with defective skulls. The peristaltic move- ments of the arteries dependent upon the vaso-motor centre are believed by Hering and others to be the result of the respira- tion of the vaso-motor centre itself. These movements are common to blood-vessels everywhere throughout the body, but, according to Hering, the stimiili causing such contractions do not always accumulate sufficiently to exert an influence with every respiratory act ; in which case the rhythm of the move- ment is altered by other influences acting upon the vaso-motor centre by stimulation of the sensory nerves. In the case of the brain, wdiich is surrounded by rigid cranial walls, and by the arachnoidal spaces, and from the fact that it is placed under considerable pressure, Meynert believes a modification of this general vascular movement is effected. The vascular wave, according to Mosso, is independent of the pulse and respiratory waves; but it may exert an influence upon the respiratory and pulse waves. The advance of the peristaltic wave within the rigid cranial walls aids in the establishment of currents of brain fluid, whereby metabolic waste products are carried off" through the lymphatic fluids. The brain and the flviid surrounding it are subjected to a certain mean pressure, \\'hich depends upon the blood-pressure within the vascular system. Naunyn and Schreiber showed that cerebral pressiire must be slightly less than the pressure within the carotid before the symptoms proper to pressure on the brain occur. The vascular wave causes a hemispherical protrusion of the cerebral mass, followed by a bowl-shaped contraction. The height and length of this wave are not equal. The wave flattens in a cool bath, and it is raised in a warm bath. It is most distinct and regular during sleep ; during the hours of waking its regularity is interfered PULSATORi' MO^'ExMENTS. 77 with. Moderately warm baths of 77-79° Fahr. lessen the number of waves, but make each wave longer; warm baths increase the number and shorten the single waves, (Meynevt). In one of Burckhardt's patients a sudden fright, follo^^■ed b}- an unexpected noise, caused a rapid rise in the curve, followed by a fall. Whilst another patient ^^'as playing at chess low but long extended waves, with a few larger perturbations, were noted. He also found that while doing arithmetical ^^^ork elevations were noticeable at the beginning and at the end, whilst in between depressions were more frequent. Meynert concludes, that all stimuli acting upon the sensorium create vascular movements, and disturb the periodic changes in the condition of the vessels ; and that, of the psj^chical influences which may cause elevation, the emotions act more readily, and bring about a greater change than purelv intellectual processes. Great variations of brain-pressure are almost constantlj^ attended by symptoms of disturbances of the nutrition of the brain. If the pressure is moderate the symptoms ma}- remain latent, or only show themselves as headache, vertigo, weakness,, or disturbance of the sensory functions. During sleep the circiilation of the lymphatic fluid in the brain effects the removal of the waste products, and this, to a great extent, is dependent upon the vascular movements of the brain. Burckhardt regards the influence of this vascular wave as far more powerful than that of the respiratory wave : the irregularities of vascular wave-movements, which occur ^^•hen the individual is awake, indicate that in certain parts of the brain there is an independence of action, just as we know to be the case in reflex arterial constrictions on the surface of the body. Let us now consider the so-called '' jmlsatort/ movements " of the brain. From the circle of Willis the arteries ascend and their currents are directed upwards, as is also the case with the venous currents. The arteries at the base are the first to en- large with the blood-flow ; then the wave passes into all the branches of the vessels. The brain, however, is only able to enlarge concentrically toward the ventricles, on account of the resistance offered by the roof of the skull to the swelling of the convolutions. This concentric swelling of the brain is almost constant, and the pressure is neutralised in the ventricles in 78 BRAIN-MOVEMENTS. part by the circiTmstance, that, with the increased pressure arising from the flow of blood through the shorter arteries of supply to the basal portion of the ventricles, there is first an equivalent displacement of the cerebro-spinal fluid within the ventricles ; then, when the engorgement of the walls of the ventricles diminishes, the blood-supply through the longer arteries to the cortex is forced by the cranial walls downwards toward the dorsal aspect of the ventricles. In this way less active movement of the cerebro-spinal fluid is brought about than if the basal and dorsal aspects of the ventricles were engorged simultaneously. The cerebro-spinal fluid finds its way through the foramen of Magendie, and to all the cisterns in general, so that the concentric pressure influences not only the contents of the ventricles, but also all the lymph-spaces. Meynert also points out that the engorged parenchymatous arteries effect the exudation of lymphatic fluid from those perivascular spaces which lie between the blood-vessels and the adventitia, so that the systolic pressure is still further neutralised. Coincidental with the basilar constriction the upper parts of the brain are pressed against the cranial roof, and with the increased pressure within these parts resistance is offered to the advance of basilar cerebral fluid. In addition to the escape of fliiid through the foramen of Magendie, during the first phase of the vascular systole, a certain amount flows into the veins of the choroid plexus. With the systole of the superior cerebral arteries, we have the simultaneous occurrence of the basal diastole ; but the displaced cerebral fluid does not now return to the ventricle. In consequence of the swelling of the basal portion, the diastole pushes the Huid past the upper cerebral parts (which have been removed to a distance from the skull by the arterial systole) into the Pacchionian bodies and the sinuses, and then into the basilar nerve-sheaths and into the cervical glands. The return of the ventricular fluid is still further prevented by the increase of ventricular fluid secreted b}^ the choroid arteries during their diastolic dilatation. Quinke injected cinnabar into the spinal subarachnoidal spaces, and found that the greater portion penetrated as far as the Pacchionian glands, the dura, the sheaths of the cerebral nerves, and to the cervical glands, but jiot to the ventricles, or perivascular spaces between the pia and NUTRITION OF NERVE-ELEMENTS. 79 media of the arteries. The explanation of this, as offered by Btirckhardt is, that, if an artery, lying in the midst of a peri- vascular space which communicates with the subarachnoidal spaces, contracts, lymphatic fluid will pass from the parenchyma into the perivasciilar space (in a direction opposed to the course of the injection from the cerebral surface into the perivascular space), because the passage to the subarachnoidal spaces on the convexity of the brain is now unobstructed ; but if this artery in the perivascular space be dilated, it obstructs this passage by filling out the above space, and no cinnabar will be allowed to enter the subarachnoidal spaces. During this stage the lymph- current is impelled toward the veins, as by the pulse wave, which, with less success during cardiac systole, enables parenchyma- tous lymph-fluid to be absorbed by the veins, and, during cardiac diastole, opens up the passage into the subarachnoidal spaces. The act of inspiration causes a fall, whilst that of expiration causes an elevation of the piilse-wave. This influence is most noticeable during forced efforts of expiration, and depends upon variations in the venous pressure. This venous pressure acts retrogressively upon the cerebral venous sinuses. Startino- from the torcular, the stasis occurs first in the longitudinal sinus, and the comparatively short sinus rectus ; hence the veins of the cortex are sooner affected than the longer veins of the choroidal plexus. As the result of this venous pressure, con- centric swelling of the hemispheres occurs, although less frequently than was the case with the pulse-wave ; the venous pressure also acts from the vertex downward, instead of from the base upward, as does the pulse-wave. From these brief considerations of the arterial supply, the movements of the brain during systole and diastole, and the movements of the cerebro-spinal fluid, we can gain some idea as to the mechanism of nutrition of the brain ; but as yet we know little or nothing of the modes of nutrition of the individual nervous elements, and it is to this part of our subject that we must now pay attention. Nutrition of Nerve-Elements.— The fact that, when motor or sensory nerves are cut, they begin to die at their central or peripheral ends respectively, suggests to us the presence of some mode of nutrition other than that dependent upon the plasma of the blood. This other condition is found in 80 BRAIN-MOVEMENTS. the influence of stimulation and conduction. The non-medul- lated tissue of the axis-cylinder exercises a strong attraction for nutritive plasma, but this is rendered more effective by the mediation of stimulation. During the processes of stimulation and conduction the axis-cylinder is better able to attract nutri- tion from the plasma, and to increase the chemical changes involved by the intensity of the nerve-current. The sheath of the axis-cylinder, consisting, as it does, of horn}" and glutinous substances, has been compared by Meynert to a sieve, which allows the nutritive plasma, as much of it at least as is attracted from the white substance, to fall upon the axis-cylinder, not with the intensit}^ of a full current, but with the more delicate force of rain ; and we must regard the partial endosmotic permeability of the neuro-keratin sheath as an apparatus regulating the phj^siological needs of the axis-cjdinder. Rumpf has shown that the nutrition of the axis-cjdinder depends in part upon stimuli, and therefore upon the axis-cylinder's connec- tions with a peripheral sense organ and a central organ. In the brain there is a larger proportion of water than in nerve-fibres generally, and possibly this fact has some relation to the lessened tension (through absence of the sheath of Schwann), and conse- quent greater exudation of plasma. Owing to the denser supply- of blood-vessels to the cortex there is also a relatively larger supply of plasma to the axis-cylinder. In the grey substance generally, there is a larger percentage of water than in the white, and the nutrition of the former is almost entirely dependent uj)on its blood-supply ; thus, in this way, it differs somewhat from the indirect and independent mode of nutrition of the axis-cylinder. The nerve-cell is also surrounded by a perforated keratin- sheath which regulates its supph- of nutritive plasma. In the grey substance of the cortex there is less danger of suffering from aneemia than elsewhere. This is to be accounted for by the independence of the ganglion-cells and the axis-cylinder, which, under the influence of attraction, stimulation, and con- duction, are rendered, to a certain extent, safe from vascular disturbances. The nutritive function of the nucleus over the albuminoid substance, is insisted upon by Meynert, who also infers a direct relation between albuminoid substances and the percentage of phosphorus. The influence of the nucleus upon VASO-MOTOK CENTRE. 81 the nutrition of the cell has already been alluded to ; and as nuclein contains a relatively large proportion of phosphorus, its influence by some is regarded as of importance, especially in the regeneration of tissues in pathological processes. In order that we may be better able to understand the mechanism of the so-called " fu7ictional hyjjercemias " of the brain, we must retmni to the consideration of some anatomical and phj'siological condition of the cerebral mechanism, upon the efficiency of which the nutritive processes of the brain in great part depend. The vaso-motor centre is looked upon as the chief centre which supplies all the non-striped muscles of the arterial system with motor nerves, termed " vaso-motor," " vaso-con- strictor," and " vaso-hj^pertonic " nerves. Under ordinary con- ditions this vaso-motor centre is in a condition of moderate rhythmical tonic activity. When this area is stimulated there occurs a general increase of arterial blood-pressure through contraction of all the arteries. Paralysis, on the other hand, causes a fall of blood-pressure through relaxation and dilatation of all the blood-vessels. This centre can be excited directly or reflexly. It shares also, with some other centres in the medulla oblongata, the functions of dominating or controlling similar centres placed elsewhere. The assumption that there is a continuous, regulating, and inhibitory action of this centre upon the heart through the fibres of the vagus, is, according to Bernstein, not, in realit)^ sufficient, for there is a reflex condition effected through the abdominal and cervical sympathetic. All the three cervical sympathetic ganglia, in some degree, supph' vaso-motor power to the spinal cord and brain. The superior cervical ganglion, by its connection with the lenticular ganglion, has power over the movements of the iris ; by its association with other cranial nerves it takes part in the secretion of saliva, tears, nasal, and pharyngeal mucus ; it supplies vaso-motor fibres to the external carotid and its branches ; it also sends branches to the internal carotid which it follows within the skull, innervating the dura mater, the vessels of the anterior and middle brain, both basal ganglia and cortex, the latter through the vessels of the pia mater. It is not yet definitely known whether this superior cervical ganglion is the onl}^ vaso- 6 82 BRAIN-MOVEMENTS. motor centre for these portions of the brain, or only the chief one. When there is ablation of this ganglion, vaso- motor influence may gradually be supplied by nerves from the cervical plexus, by fibres from the pons, medulla oblongata, and upper part of the cord. The middle cervical ganglion supplies vaso-motors to the thyroid gland, and to the larynx and part of the trachea. The inferior ganglion supplies vaso-motors to the vertebral and basilar arteries and their branches. * It has not yet been proved how far we may regard the cortex as possessing vaso-motor centres. With arterial systole Ave have vaso-con stricter influence, and with the arterial diastole we have vaso-dilator influence at work ; but, as pointed out by Meynert, mental processes are not interrupted by arterial systole ; therefore they must, to a certain degree, be independent of functional hypersemia. Meynert thinks that this independence of mental acts may possibly be due to the fact that the cortex itself acts as a vaso-motor centre in its relations to subcortical centres; and, arguing from the evidence of the influence of cerebral activity over the vaso-motor centre, he concludes that the vaso-motor nerves of the cortex do not reach the blood-vessels at once, but that they are interrupted in the subcortical vaso-motor centre ; and that these sub- cortical centres must be constantly in a state of activity for the vascular innervation of the cortex. Every sympathetic ganglion is a vaso-motor centre, possess- ing some independence of action, but more or less controlled by a higher ganglion of this extensive system. The vaso- motor nerves of the cranium come from the cervical sympa- thetic ganglia, and are arranged in two plexuses in the vessels of the brain — one in the external tunic, and one in the middle tunic of the artery. The veins, possessing less muscular tissue, receive fewer nerve-filaments. Whether the nerve-filaments terminate outside the muscular elements, as maintained by Krause, or penetrate into the interior of the smooth fibres, as believed by Henocqiie and Arnold, is a problem which we are not prepared to solve. The terminal fibres of these small plexuses of the arteries end by punctiform swellings in the * Long Fox, " Influence of the Sympathetic on Disease," ]). 13. VASO-MOTOR CENTRE. 83 nucleus, or in the fibre ; or extend along the interstices of the fibre cells. In the veins their terminations are similar ; and in the capillaries the fibrils probably end in the nuclei of their walls. Some ganglion-cells are interposed in a bundle of sjnnpathetic nerve-libres ; others have prolongations of their substance on the axis-cylinder of the nerve-fibre. A partial independence of these sympathetic ganglia is manifested in various phenomena — viz., (a) nutrition may be carried on in spite of destruction of the cerebro-spinal centres, supporting the view of Goltz. that local centres are able to maintain the tone of arteries within their own iinmediate vicinity ; (/>) reflex irritation of vaso-motor nerves may be limited to the par- ticular tissue supplied, as seen in the continuance of the lieart's action after its separation from the body ; (c) vaso- motor neuroses of the extremities ; automatic and reflex co-ordinate movements and secretions are known to occur apart from the influence of the cerebro-spinal centres ; (d) the stimulus of the blood itself acts reflexly upon vascular tone, and the phenomena of blushing, and local hyperaemias further indicate the partial independence. When we consider the partial independence in the action of this complicated sym- pathetic system, and the dependence of action brought about by association with the cerebro-spinal system, we readily appreciate the dictum that. "' The use of the central cord of the sympathetic is to make the animal and the vegetative worlds known to each other, so that revictualling should be dispro- portionate to waste."* The independence of the vaso-motor portion of the sympathetic is also shown in many conditions of shock or injmy to this system. Woakes has pointed out the relation between injury of the nerves of the brachial plexus and loss of conscioiisness, the resulting shock of the former being propagated to the inferior cervical ganglion, and thence to the vertebral artery, and all its branches. We can state, therefore, that, under cei'tain conditions, sympathetic ganglia may act as independent centres for reflex acts. The import- ance of this fact, in the production of variations in the vaso-motor conditions in the brain, cannot be over-estimated, * Fox, op. cit. p. 43. 84 BRAIN-MOVExAIENTS. especially when we seek to understand the etiology of brain disorders.* It is not part, of our object, however, to enter npon the nnnierons questions of innervation of the vessels, and space will not permit us to consider all the conditions under which contractions, dilatations, and reflex vaso-motor effects occur. The statement, that the mutual interaction of vaso-dilator and vaso-constrictor nerves, plus the factor of cerebral inhibition, are the main elements in the regulation vaso-motor tone in the brain, must suffice for the present. At the same time, bearing in mind that the local circulation is regulated mainly by the motor nerves, which issue from the ganglia of the sympathetic, and extend along the arteries throughout their entire course. This vascular tone is altered by pathological changes in the vessels themselves, as in atheroma, fatty, calcareous, and amyloid degenerations, senility, s^^philis, alcoholism, etc., and it is of importance that \ye should take account of the action of the sympathetic system as a causal factor of pathological conditions, which are known to exist with various morbid mental states. Althann.f more than twenty years ago, pointed out that fulness of cerebral vessels was no measure of the good or bad blood-supply of the nervous elements ; but that oxygen was more readily brought to, and carbonic acid more readily removed from, these elements under such conditions. He regarded this as depending upon (n) the chemical constitution of the blood, and (//) the quantity of blood that passes through the capillaries in a given time. For an even and satisfactory * Long Fox believes that in those forms of hysteria that depend upon definite uterine or ovarian lesion, tlie deep-seated sense of pehic uneasiness, nearlj' similar in position and sometimes equalling in intensity the sacro- coccygeal pain attending piles, the paresis of intestine e\inced by meteor- ismus, the increased flow f)f limjjid urine, the vomiting, the hiccough, the frequent diarrlicea, the ])alpitation, the faintness, the sighing respiration, the globus, the difficulty in deglutition, the blushing, the dilated pupil, the tears, tlie tinnitus, the excitation of tlie emotional area, the occasional epilepsy, melancholia, mania, to which sucli patients are liable, are all examples of afferent irritation carried to the solar j)le\us, and thence, from ganglion to ganglion of the sympathetic chain, to the three cervical ganglia ; thence to the eye, the cereliral vessels, and the medulla oblongata. t, Geigel, " Virchow's Archiv.," vol. cxix., ]>. 93. VASO-MOTOR CENTRE. 85 How of arterial blood through the capillaries Geigel employed the term •'euditemorrhysis," whilst too little blood (true anaemia cerebri) and too much blood (true hypersemia cerebri) were termed " adisemorrhysis " and ''hyperdiaemorrhysis" respec- tively. The same author stated that the velocit)^ of the circu- lation of the blood in the capillaries of the brain is directly proportional to the arterial pressvire, and inversely proportional to the resistance ; and that the resistance depends directly upon the amount of intra-cranial pressure ; therefore (as Fick has shown that the intra-cranial pressure is equal to the intra- arterial pressure, less the resistance which the tension of the arterial walls oppose to it), (1) if the contraction force of the arterial wall gets less, intra-cranial pressure will increase and the velocity will become less — i.e., dilatation of an artery causes anaemia, and not hyperaemia ; (2) contraction of the arteries of the brain will increase the velocity of the blood-flow through its capillaries. Again, suppose the heart acts more powerfully, raising intra-arterial pressure, while, at the same time, the arterial walls increase their contraction, intra-cranial pressure will be the same, or greater or less, according as the arterial contraction equals, or is less or greater than the rise of, intra- arterial pressure. Hence, with increased contraction of arterial walls, intra-cranial pressure decreases and capillaries widen. On the other hand, with diminished contraction of arterial walls intra-cranial pressure is raised, the capillaries are com- pressed, and the amount of blood circulating through them is diminished.* Geigel believes that the symptoms of cerebral pressure are realh^ due to the interference with the circulation which the pressure produces, and are not the direct result of the pressure on the cei'ebral substance ; and in support of this he points out that, provided the cerebral circulation is not interfered with, the brain-substance will withstand a pressure of two atmospheres and more without harm. The symptoms of high intra-arterial pressure and of anaemia are very similar, because the supply of oxygen and the removal of carbonic acid are equally interfered with in the two conditions. Geigel regards the effects of embolism or rupture of a vessel as somewhat * Haig, "Brain,"' p. 315. 86 BRAIN-MOVEMENTS. similar ; embolism or rupture of one intra-cranial artery pro- ducing temporary diminution of circulation in all the other intra-cranial vessels, and the apoplectic shock of embolism is thus due to diminution of blood-supply. Lewy* believes that this argument holds good only under certain pathological conditions, but denies that it does so for physiological conditions. His views are : (1) that an intra^ cranial artery cannot expand without taking space from other vessels, the space thus taken being so small, that in physiolo- gical conditions it affects the cerebro-spinal fluid, but not the capillary circulation at all ; (2) that when an artery enlarges, the blood meets with less resistance in passing through it ; and possibly the lessened resistance in the arterj- more than compensates for any slight increase of resistance in the capil- laries due to the expansion of the ai'tery ; (3) that, conversely, contraction of an arterj^ i^^ay increase the resistance more than the corresponding relaxation of capillaries diminishes it ; (4) that, when the arteries all enlarge together, the lymph gets out of the way, and the capillaries are so numerous that they will bear a large amount of compression before they are so far closed as to hinder the circulation ; and under these conditions narrowing an artery diminishes the blood-stream, and widen- ing an artery increases it, so that arterial hypersemia is possible. But beyond a certain point this does not hold, for if we imagine the arteries to enlarge so much that the veins are pressed flat, absolute stasis will result ; if the arteries now begin to contract, passage of blood will begin again and increase, and thus a narrowing of the arteries produces hyperaemia ; (5) if. however, part of the intra-cranial space is taken up by a tumour, or, again, if a large number of capillaries have been destroyed b}' injury or inflammation, then a smaller amount of arterial en- largement maj^ seriously interfere with the capillary circiilation, Grasheyt has shown that stasis in the veins maybe due not only to the enlargement of the arteries, but also to a rise of intra-arterial pressure. When this pressiire rises beyond a certain height the central veins begin to vibrate, and then the * " VirchoAv's Arcliiv.,"' vol. cxxii. p. 146. t " Experimentelle Beitriige zur Lehre von der Blut-Circulatiori in der Schiidel und Ruckgratshtihle." .1. l'\ Lehmaiin, Miinchen, 1892. VASO-MOTOR CENTRE. 87 amount of blood streaming through is decidedly reduced. At this point it is possible that the symptoms of pathological brain- pressure begin. Grashey believes that true hypersemia cerebri is not pro- portional to arterial contraction, for, if the spastic contraction of arteries is very great, the blood-stream may be stopped alto- gether, and contraction or dilatation of arteries must influence intra-arterial pressure. Contraction of an artery diminishes, whilst dilatation increases, the pressure in it; therefore, dilata- tion of an intra-cranial artery increases the pressure on the veins and does harm. For the proper nutrition of the brain, a diminution of the amount of blood passing through the cerebral veins is unfavourable. When the veins and capillaries become overfilled with blood, the blood, as a result, is only able to move slowly. Grashey also believes that stasis in the veins adds to the intra-cranial pressure by causing an increase in the amount of cerebro-spinal fluid. These effects of a dilatation of a cerebral artery are observed in the case of local dilatations only. The points of importance in the observations of these authors are : — (1) That proper nutrition of the nervous tissues depends moi'e upon freedom of circulation than upon the quantity of blood ; and (2) that nutrition is carried on imperfectly if there is venous or capillary stasis through high intra-cranial pressure. Burckhardt's experiments go to prove, that the activity of the hemispheres modify the influence of the vaso-motor centre upon peristaltic vascular movements ; and that in sleep, when this activity is lowest, the vascular movements are most regular. Meynert refers the vaso-motor centres, which govern cortical influence, to the grey substance of the anterior division of the brain-trunk, in which are situated, also, the other motor tracts, subject to centrifugalh" transmitted cortical innervation. Further, if the cortex be excited in its capacity as a vaso-motor centre, the influence of the arterial systole upon the vaso-motor centre will be augmented, thus causing active ansemia of the brain, which, as a rule, remains entirelj' independent of the anasmia of the rest of the body. But since a functionally active cortex cannot impede the development of functional hyperaemia, we must assume that the physiological excitation 88 BRAIX-MOVEMENTS. of the cortex increases, in a centrifugal direction, the arterial diastole which forms part of a peristaltic movement. Meynert also believes, that deficient or diminished cortical activity, as seen in various psj^^chical conditions, is attended by an increase of excitation of the vaso-motor nerves connected with this part of the cortex, and thereby affects the blood-snpply as well as the chemical changes in the brain, and that increase in functional activity of the cortex is attended by diminution of cortical vaso-motor influences. Whence, he says, it follows that a cortical process of association by inhibiting vascular innervation will result in immediate functional hyperasmia. He seeks to explain, that the cortex in a state of func- tional activity imparts an impulse inwards (centrifugally) to the vaso-motor centre, and, that in some way or another, this impulse is transmitted in a centripetal direction from the siibcortical centre reacting upon the vascular system. The view, that hyperaemia of the superior surface of the brain occurs in direct relation to psychical activity, is supported by the observations of Mosso, Batty Tuke* and Gibson, who have each made observations upon this point. Batty Tuke, however, regards it still as an open question, as to whether this functional hyperaemia is produced by reflex inhibition of the vaso-con- strictor centre by direct action of vaso-dilator fibres, or by a combination of the action of the two systems. From these considerations, as to the complex conditions of nutritive supply, we are now in a position to appreciate how essential to mental life is the proper working of the mechanism whereby nutrition of the nervous elements is effected. It need, therefore, scarcely be urged that, if our object be to understand how morbid psychical manifestations may arise through defect of, or interference with, the effective working of the cerebral mechanism, the study of the varying conditions of nutrition of the brain is of primary importance to us, and the importance of it to us can scarcely be over estimated. * " On the Insanity of Over-exertion of the Brain," j). 18. 89 CHAPTEE III. Scheme of the Central Nervous System. Sensory Paths — Cerebral Localisation for Touch — Course of Sensory Fibres — Special Senses: Sight, Hearing, Smell, Taste — Motor Nerves : Cerebral Localisation — Projection Systems : Association Fibres, Fimbriae Proprise — Value of our Knowledge of Cerebral Localisation : Phrenology, Experimental Research, Compara- tive Anatomy, Morbid Anatomy — Sensori-Motor Areas and their Relations to Mental Faculties : Views of Hitzig, Ferrier, Munk, Waller, etc. — Conclusions. SCHEME OF THE CENTRAL NERVOUS SYSTEM. Hitherto we have considered certain nervous elements, as far as possible, according to their individual anatomical and physiological peculiarities. It is now our task to obtain a general view of the chief arrangements of these individual parts in the complicated structure of the brain. A description of the manner in which the elements are combined is obviously indis- pensable to us. For convenience we shall consider the general scheme of the central nervous system in its triple form, both anatomically and physiologically. We shall, therefore, so far as may be essential to our pur- pose, attempt to comprehend the complicated system of afferent, associative, and efferent nerve-tracts as a systematic whole, and it is obvious that the consideration of every psychical process deemed to have a demonstrable physiological correlative involves, at least, the study of some part or other of this system. It is known to every student that the grey matter of the cerebrum is placed external to, and spread as a thin coating over, the white matter of the centrum ovale. The folding of this grey matter into gyri or convolutions, and their anatomical 90 SCHEME OF THE CENTRAL XERVOUS SYSTEM. lines of demarcation, by means of fissures or sulci, are facts also equally well known. Nor do we need to enter upon a descrip- tion of the arrangement of the masses of grey matter at the base of the brain, which form the corpus striatum (the caudate and lenticular nuclei), the optic thalamus, the corpora quadri- gemina, and the red nucleus and locus niger within the tegmentum of the crura cerebri. The formation of the central grey tube as a continuation of the grey niatter of the cord through the medulla, pons, round the iter, and ending at the tuber cinereum. is a study of great complexity ; and the variety of ways in which these various parts are connected with each other, by transvei-se fibres stretching between the two sides of the brain, or by longitudinal fibres extending from the hinder and lower to the fore parts of the brain, is worthy of careful consideration. The cortex cerebri, as we have already seen, contains in its structures the elements which are i*egarded as being most closely associated with psychical action. To it, all the fibres coming from sensory organs, proceed, and the}' convey the effects of peripheral or external stimulation to the region, of regions, where psychical perception of external agents is siipposed to take place. Our knowledge of these sensory- paths is, as yet, unsatis- factory and wanting in precision. Sensory impulses enter the spinal cord b}" the posterior nerve-roots, and may pass, if to the cerebellum, through the cerebellar tract and pos- terior column to the restiform body, and thence to the cere- bellum ; or, if to the cereT)rum (after decussating in their course in the cord), through the posterior half of the pons, into the tegmentum of the crus under the corpora (juadrigemina, to enter part of the posterior third of the posterior segment of the internal capsule. The subsequent course of these fibres, however, is somewhat doubtful ; some fibres enter the optic thalamus (Meynert) ; others j^ass into the white matter of the cerebrum. According to Meynert, the sensory columns of the cord turn suddenl}' back from the postei'ior third of the internal capsule, and are distributed to the occipital and temporo- sphenoidal lobes. From the occurrence of impairment of tactile sensibilitv, associated with disease of the motor regions CEREBRAL LOCALISATION FOR TOUCH. 91 of the cortex, Gowers asserts that some of these fibres go to the parietal and central regio.ns. Whether some of the fibres pass into the optic tlialamus, or whether they have no connec- tion witli it, but pass, as stated by Bevan Lewis, uninterrup- tedly between the lenticular nucleus, thalamus, and caudate nucleus, to their cortical termini, is not yet clearly decided. Ferrier found that, when parts of the gyrus hippocampi Avere removed, loss of sensation occurred on the other side of the body. Horsley and Schafer found similar results from destruction of parts of the gyrus fornicatus. Horsley has also found that when parts of these gyri were removed in man, there was slight loss of sensation ; the patient being unable to feel very slight touches of the limb, and the point localised as touched was usuall)' a segment higher up than the actual point touched. The observations of Flechsig, Monakow, and Dejerine seem to demonstrate that the course of the sensory paths (kinsesthetic) is up the posterior columns of the cord, through the posterior column nuclei, the internal arciform fibres ; thence, after decus- sation, by the inter-olivary tract and fillet of the opposite side to the posterior part of the internal capsule, and eventually to terminate in the central convolutions. Mott* has demon- strated that the so-called motor cortex is concerned with the reception of afferent sensory impulses. This view is supported by the experiments of Hitzig, Munk, Luciani and Seppili, Tripier and Moelli. Horsley found undoubted sensor}' defects following the removal of large portions of the Rolandic area in man. Allen Starr has endeavoured to demonstrate that the tactile sense-centres are situated in the Rolandic area, especially behind the fissure of Rolando. Wundt, Bastian, and James agree that the central convolutions possess sensory functions. Mott considers that this view is fully supported by the facts of anatomy, embryology, experimental physiology, pathology, and clinical observation. To account for tire fact that the motor paralysis is greater and more permanent than the loss of sen- sory functions, Mott compares the expansion of the centrifugal and centrij)etal fibres of the internal capsule to two funnels ; the fibres as they lie in the capsule forming the tubes, and expanding * "British Medical Journal," Sept. 1893, p. 685. 92 SCHEME OF THE CENTRAL NERVOUS SYSTEM. above like cones, the bases of each of which are nearly coinci- dent although the tubes are not. He says there is one important diiference, however ; the base of the efferent cone is made up of axis-cylinder processes jnst after leaving the cells from which they grow ; that is (comparing a nerve-fibre to a tree), the base of the efferent cone consists of the trunks, from which all the branches and collaterals spring. The base of the sensory cone in the cortex consists only of the terminal twigs of the afferent nerve trunks. As the afferent fibres to the cortex form an arborisation before terminating in the grey matter, it is con- ceivable that a small portion of grey matter of the area con- nected with tactile perceptions will suffice to restore function, but removal of the base of the efferent cone prevents anj^ volun- tary motor impulse starting. So far, however, it has been found impossible to localise accu- rately the areas which represent the different parts of the body. On the groiinds that definite localisation of the centres of sight, hearing, smell, and, probably, taste, as well as the respective motor centres, is possible, Ferrier assumes there must be a definite region for the various forms of sensibility included generally undei- tlie sense of touch, contact, pressure, tempera- ture, etc. He says,* that up to the point of radiation into the cerebral cortex, the sensory paths have been proved to be entirely differentiated from the motor; and that the two should become jumbled together indiscriminately in the cortical centres is a hypothesis which, prima facie, is extremel}^ unlikely. In the spinal cord the sensory and motor nerves are distinct from one another. In the pons and crura cerebri they still remain apart. The observations of Veyssiere, Charcot, Reymond, Rendu and others, go to prove that in the internal capsule the sensory tracts are quite distinct from the motor, and may be injured or diseased separately, caiising hemianesthesia on the opposite side of the body as the result.f "When the region of the sensory paths in the internal capsule is divided, volitional movements can be effected, but there is no corresponding consciousness by means of the muscular sense. Ferrier asserts, that the same condition which abolishes cutaneous sensibility also entirely annihilates * " Functions of the Brain," 2nd edit., p. 323. + Fen-ier, ibid., p. 323. COURSE OF SENSORY FIBRES. 93 the so-called muscular sense ; and that there is no necessary relation between the power of effecting- movement and the sense of movement effected — i.e.. the paths of muscular sense are quite distinct from the paths of volitional impulse. Flechsig maintains, that the tracts forming the outer third of the foot of the ci-us radiate from the internal capsule out- wards and downwards towards the hippocampal region. Ferrier found, that destructive lesions of the hippocampal region caused profound impairment or total abolition of cutaneous, mvTCo-cutaneous, and muscular sensibilit}^ ; and that the degree of duration of the aneesthesia varied with the completeness of destruction of the region in question. Since, however, recovery sometimes takes place after the removal of the hippocampal region only, Horsle}' and Schiifer made additional experiments, and found that destruction of the gyrus fornicatus alone could produce analgesia and anaesthesia of the opposite side of the body. The falciform lobe is now regarded as the cortical centre of those fibres of the internal capsule, destruction of ^\'hich is the cause of hemianaesthesia of organic orig-in.* The sense of movement (kintesthetic sense) will be con- sidered with more convenience when we come to study the motor centres; so we leave this subject for the present and take up briefly that of the special senses. Sight. — The most important of the special senses is that of sight. Gratiolet believed the optic tract to be directly con- nected with every part of the cerebral hemisphere, from the frontal to the occipital lobe in man. Hamilton has demon- strated that its connections are very numerous ; but the obser- vations of Gratiolet have not been confirmed. Certain fibres are connected with the basal ganglia, whilst others are con- nected with the cortex. The former probably arise from the * Ferrier says : — " The symptoms observed in the animals operated on prove that the centres of mere touch proper are precisely the same as those of painful sensation— whether from pressure, heat, or otherwise — the latter being merely an intense degree of the former." " All the facts receive the most satisfactory explanation, if we regard the falciform lobe as a whole, and in each and everj- part the centre of tactile sensation for the whole of the opposite side of the body ; though probably the various motor centres are each anatomically related by associating fibres with corresponding- regions of the falciform lobe. The association would form the basis of a musculo-sensory localisation." — '• Functions of the Brain," p. -344. 94 SCHEME OF THE CENTEAL NERVOUS SYSTEM. corpora geniculata, piilvinar. and anterior quadrigemina, and from the substance of the tlialamus ; whilst the latter (cor- tical fibres) join the former to form the optic tract. In the frontal region, the connection with the cortex is effected through " Meynert's commissure " (Hamilton).* To attempt to elaborate or explain the relation of the fields of vision of the retina, tracts, and the cerebral optic centre, is obviously outside our object ; nor can we undertake to explain some of the eye-symptoms which occasionally occur in cerebral disease. Gowers states that affections, (a) of the optic nerve (between the eyeball and the chiasma) — i.e., in the orbit, optic foramen, or within the skiill — affect one eye only ; (//) of the middle of the chiasma, cause temporal hemiopia; (c) of the optic tract (between the chiasma and the occipital cortex), cause hemiopia, which is always symmetrical. The centre for sight has been localised in the angular gyrus, around the posterior end of the parallel sulcus, and in the occi- pital lobe. Ferrier, Horsley, and Schiifer have found that complete permanent hemiopia for the opposite field of vision is only produced when both these parts are removed. If one occipital lobe be ablated, there is hemiopia for the opposite field of vision, but this is of a temporary nature. Ferrier has also found, that when the angular gyrus of one side alone is removed, complete blindness of the opposite eye is caused, from which, however, the animal soon recovers. Gowers regards * According to Hamilton, other cortical connections join the tract as it -winds round the cerebral peduncle. These other connections comprise — (1) a large mass of fibres coming from the motor areas of the opposite cere- bral hemispheres, crossing in the corpus callosum, entering the outer cap- sule, and joining the tract directly ; (2) fibres uniting it to the temporo- sphenoidal lobe of the same side, especially the first and second temporo- sphenoidal convolutions ; (3) fibres to the gyrus hippocampi of the same side ; (4) a large leash of fibres forming the " optic radiation " of Gratiolet, which connect it directly with the tij) of the occipital lobe. There are pro- bably also indirect connections with the occipital region through some of the basal ganglia. These connections with the frontal and sphenoidal lobes are not admitted by some investigators, but all are agreed as to its connec- tion with the occipital by means of the " optic radiation." The optic radiation gives fibres to the optic tract, to the corpus geniculatum internum and externum, to the pulvinar and thalamus, to the posterior third of the poste- rior limb of the inner ca})sule ("sensitive band" of Meynert) and fibres which run between tlie island of Keil and the tip of the occipital lobe. SIGHT. 95 the angular gyrus as containing a higher visual centre, in which the half fields are combined, and the whole opposite field is represented. Ferrier believes, that each hemisphere is in relation with the corresponding half of both retinae, and that the semi-decussation of the optic tracts is maintained in the cortical centres ; and in addition to the representation of the correlated halves of both retinae in the corresponding occipito-angular region, the angular gyrus is the region of clear or central vision of the opposite eye, and, perhaps, to some extent, also of the eye on the same side. Ferrier says — " Each occipital lobe is in relation with the half of each retina on its own side, while each angular gyrus is in relation with the centre of the opposite eye, partly by fibres which are sup- posed to cross in the chiasma, and partly by fibres which reach it after decussation in the low^er visual centres — possibly the corpora quadrigemina. At the same time, also, a partial inter- mingling in the chiasma of the fibres from the centre of each eye brings each angular gyrus, to some extent, also in relation with the eye on the same side."* There are some small fibres at the posterior pai-t of the chiasma which run along the mesial side of the optic tracts to join the internal geniculate bodies of the two sides. These fibres form the inferior commissure of Chidden ; but they are not supposed to have any visual function. Darkschewitsch states that this commissure unites each mesial geniculate body with the lenticular nucleus of the opposite side.f The intercentral connections of the nervous visual apparatus are probably as follows : A set of fibres passes from the higher visual centre in the occipital lobe through the corona radiata and caudal end of the internal capsule, to the grey matter of the lower optic centres, where they end in arborisations. Another set arises in the lower optic centres, and terminates by arbori- sation in the occipital cortex. There appears to be some con- nection between the grey matter of the bulb and cord and the lower optic centres. There is some direct connection (through the tract of the upper fillet) between the cerebellum and the fibres of the optic tract. * " Functions of the Brain," p. 292. + •' Quain's Anatomy," vol. iii. pt. I. p. 118. 96 SCHEME OF THE CENTRAL NERVOUS SUSTEM. Munk * maintains that the identical points of both retinse do not correspond to the same points of the cerebral cortex, but that the external half of each retina is associated with the outer half of the visual area of the same side, and the inner half mr/ius genie, lat. mis oculomotoriiis. f cortex cerehrl. Fig. 10. Diagram of the Probable Course and lU-XATtoNS of some of the Optic Fibres. [After Schafcr and Tlicinr.) of each retina with the inner half of the corresponding visual area of the opposite side. The relation of the visual area of the cerebral cortex to eye-movements is not yet definitely settled ; nor do we know the exact connection l)etween the optic centres * "Tlie Visual Area of the Cerebral Cortex."— " Brain," 1890, \^. 45, SCHEME OF THE CENTRAL NERVOUS SYSTEM. 97 and the nuclei of the nerve to the muscles of the e'lobe of the eye. It is thought possible that this connection may be partly effected through the posterior commissure and posterior longi- tudinal bundle, and that it is probably both crossed and uncrossed. Munk found that stimulation of the cortex (in dogs) somewhat beyond the anterior border of the visual area, or beyond the lateral border of the visual area in the auditory centre caused cessation of eye-movements. When these movements do occur they are supposed to be the results of locally-restricted stimulations of portions of the visual area. When there is total extirpation of both visual areas, perfect blindness results, but eye-movements ma^^ remain intact, except those which are entirely dependent upon vision. Munk regards the visual area as having nothing to do with those eye-move- ments Avhich are independent of sight ; neither do these move- ments result from excitation of the visual areas, nor does the path of conduction from the place of their excitation to the periphery lead through the visuah centres ; consequently the eye-movements which the electrical irritation of the visual area induces, onl}' correspond to particular eye-movements which are the results of visual perception. He further believes that, out- side the visual area, and in his "tactile sphere," there are two spots on the cortex, the electrical stimulation of which causes eye-movements ; and as one or the other spot is excited, so will the eye-muscles which are set in motion give rise to particular movements, just as arm or leg muscles will be brought into action by stimulation of neighbouring spots on the motor areas.* * " Therefore," he says, " if an animal makes a movement in consequence of having seen anything, it must be concluded that the excitation conducted through the optic nerve-fibres to the visual area is transferred by associated fibres which connect these same areas with the tactile areas, at one time by this set of associated fibres, at another time by that — according to the kind of movement produced ; and so through certain association fibres the excita- tion reaches tlie spots C or D if arm or leg-movements occur, through other associated fibres the spots F or H if eye-movements take place. In analo- gous fashion the eye-movements are obtained in our case by- excitation of the visual area with induction currents, since the excitation produced by the electrical current spreads to the centres F and H by associated fibres, which run from the visual areas to those centres, whether excitation is originated by the current in the central elements of the visual area, or in the fibres themselves where they terminate in the visual area." 7 98 SCHEME OF THE CENTRAL NERVOUS SYSTEM. Munk attaches no significance to the commissural fibres which pass out of the visiial areas into the corpus callosum. He concludes that eye-movements are caused by the electrical stimulation extending to the radiating fibres of the corona radiata which go to the subcortical parts of the brain, and that the excitation starts in the central elements of the visual area — i.e., in the radiating fibres where they proceed from the visual areas. These movements correspond more especially to those eye-movements which produce " wandering vision " and fixation of the eyes upon an object previously indistinctly seen. Further, the portions of both retinee of the corresponding side, which are on the same side of the maculae lutse, belong to each visual area ; while the upper, middle, and lower cjuadrants of those portions of the retina, belong to the anterior, middle, and posterior zones of the visual area respectively. Munk also upholds the view, that the visual nerve-fibres, after their entry into the visual area, are connected directly and immediately with the central elements which serve for the perception of light.* -Sherrington,! however, has found that, in the monkey, after a deep frontal section across the hemisphere and into the * The projection of the retinte upon the visual areas, according to Munk, presents itself now in its full significance as the substratum for the localisa- tion of the visual perceptions, since the involuntary eye-movements, which are brought about through the radiating fibres, supply the necessary com- plement. Successive and opposite positions of the objects in Helmholtz's visual fields are yielded by projections, the judgment being assisted by the sensations which bring about these involuntary eye-movements, xipwards, downwards, right or left ; thus projection and eye-movements together, permit such rapid and certain cognisance of the visual field, as we observe in animals, and which would be quite impossible if it were necessary to deliberate regarding every detail in the visual field. The discovery of the new radial fibres of the visual area will prevent the anatomical investigator from being able, without further consideration, to refer all descending degenerations which result from removal of that area to the tracts which conduct visual impressions ; but there is, on the other Iiand, now opened up to him the prospect of being able to distinguish the two kinds of central elements, and of being able to demonstrate their morphological differences — a prospect which is attractive by reason of the proved connection of the radiating fibres with the light-perceiving central elements, and of the associated fibres with the representative elements (Vorstellungselementen). "Brain," 1890, p. 65. I " Royal Society Proceedings," vol. xxxv. p. 407. "Journal of Physiology," vol. xvii., No. 1, 1894. HEARING. 99 lateral v^entricle (partly entering the internal capsnle) so as to sever occipital from frontal cortex, he could still evoke move- ments by appropriate excitation of all that portion of the cortex which, on excitation, gives conjugate lateral deviation of the eyes — i.e., from the area discovered by Ferrier in the frontal region, and from that discovered by Schiifer in the occipital region. The reaction could also be obtained by excitation of (1) the corona radiata underlying the frontal cortex after complete ablation of the cortex itself; (2) the corona radiata running downwards and forwards from the occipital cortex after free removal of the latter ; (8) the internal capsule itself at two distinct places, one in front of, the other behind, the genu ; .(4) the cross-section of the corpus callosum about 3 — 5 millimetres behind the genu ; also at the splenium. Sherring- ton concludes that the inhibition, which can be elicited by experimental excitation of the grey cortex and of the under- lying white matter, is ftilly and habitually exercised in volitional eye-movements. He also conckides that the action may take place, and probably does so usually, in centres which are subcortical ; and that the grey matter of the cortex is not essential to the phenomenon. Hearing^. — The auditory nerve is regarded not only as the nerve of hearing, but also as participating in another function — viz., that of helping to maintain the equilibrium of the body through its connection with the semicircular canals. The nerve arises by two roots : a larger anterior root, from which proceeds the vestibular nerve ; and a smaller posterior root, from which the cochlear nerve comes. Each root springs from a median and a lateral nucleus. The fibi'es from the cerebellum are regarded as being concerned with equilibration. The chief mass of the posterior ganglion fibres of the cochlear nerve cross and pass to the corpora quadrigemina, the internal geniculate body, and to the temporo-sphenoidal lobe. The strise acusticae form a second decussating projection system, and according to Flechsig, the origins of both acoustic nerves are connected by commissures in the brain. The physiological significance of the exchange of fibres between the auditory and the portio intermedia of the facial nerve is not known. The centre for hearing has been localised by Ferrier in the 100 SCHEME OF THE CENTRAL NERVOUS SYSTEM. first temporo-sphenoidal convolution. According to Munk, destruction of the entire region causes deafness of the opposite ear, while destruction of the middle shaded part alone causes "" psycldcal deafness^^ (kSeelentaubheit). Bilateral lesions of the first and second temporo-sphenoidal convolutions in man cause complete deafness. Disease of these convolutions is attended with irord-deafness. The OAiditorii paths are from the auditory nuclei in the medulla oblongata through the pons, where they perhaps cross into the tegmentum, thence into the sensorj' crosswa}', and onwards to the auditory centre.* Go^\•ers records two cases of tumoiir of the first temporo-sphenoidal convolution, in which there were fits beginning with an auditory aura referred to the opposite ear.f Equally important with these effects of disease are the sensory impressions, or " au.rce," as seen in epileps}' ; and just as a discharging lesion of the occipital lobes may cause flashes of light or coloured visual auree. so sounds or noises may arise through affection of the first temporo-sphenoidal con- volution, and usher in an attack of epilepsy. ]\IillsJ has recorded a case of word-deafness following an apoplectic seizure, and more complete deafness and partial left-sided paralysis following a second apoplex}'. In this case there were lesions of the first and second temporal convolutions of both hemispheres. The auditory centres are l")est developed in the left hemi- spheres, but in order to produce complete brain-deafness destruction of both centres is essential. When the posterior thirds of the first and second temporal convolutions of the left hemisphere are destroyed, an almost complete word-deafness is prodiiced. When a lesion is limited to the centi'e for word- hearing, and causes word-deafness, it will also cause paraphasia and ])aralexia. In time, such a lesion will lead to secondary- atrophy of the speech and oro-lingual centres, and also to affec- tions of the association tracts between the sensory and motor- hearing speech centres. The field for all auditory memories * Landois and Stirling, p. 704. t "Takes Dictionary," p. 156. X "Brain," 1891, p. 468. SMELL. 101 seems to include the posterior two thirds of the first and second temporal convolutions. When there is word-deafness there is not necessarily^, therefore, inability to recall words through other channels ; as, for instance, through their visual signs, in which case the meaning of the word maybe understood, although the name cannot be properly verified in consciousness.* Smell.— The olfactory centre, as inferred from anatomical considerations and direct experimentation, is probably localised in the anterior extremity of the temporo-sphenoidal lobe. Ferrier has found, that destruction of this part produced loss of smell on the same side in monkeys. Hughlings-Jackson, and Beevorf have published a case in which there was a growth in the right hippocampal lobule, associated with epi- leptic fits, which were preceded by the sensation of an un- pleasant smell.^ The olfactory bulb and tract, in respect of structure and connections, are regarded rather as constituent parts of the cerebrum than as a true nerve. The tract is a triangular band of white matter, inclosing a central grey neuroglia substance. It lies in the olfactory sulcus parallel to the longitudinal median fissure. Anteriorly, it is continuous with the olfactory bulb, which rests on the cribriform plate of the ethmoid bone, and receives the fibres of the olfactory nerves, which . come from the cells of the olfactory mucous membrane. Posteriorly, it bifurcates into two roots — mesial and lateral — which diverge as they pass backwards, and in- close (1) a space (the trigonum olfadorium), which is known as the middle or grey root of the tract ; and (2) a portion of grey matter lying between the mesial root and the peduncle of the corpus callosum, and continuous with the commencement of the callosal gyrus. § The mesial root, in passing over the ti'ir/ommi olfadormm, subdivides it into two parts. Fibres pass from this root to the area of Broca, and others pass directly from the posterior end of the tract into the trigonum, to join the anterior commissure, and thence to the posterior part of the temporal lobe ; or, according to Meynert, they may cross in this commissure to the temporal lobe and hippocampal region of the opposite side. Fibres from the postei'ior end of the * Mills, "Brain,"' 1891, p. 468. t "Brain," part XLVII. X "Take's Dictionary," p. 156. § Quain, vol. iii. pt. I. p. 159. 102 SCHEME OF THE CENTRAL NERVOUS SYSTEM. olfactory tract also pass directly into the white matter of the frontal lobe.* The outer root consists of a band of medullary fibres, which passes along the outer part of the anterior perforated space, to disappear about the posterior border of the Sj'lvian fissure. It has been traced by some to the island of Reil, the optic thalamus, and to a nucleus in the substance of the temporo-sphenoidal lobe. in front of the anterior extremity of the hippocampus. Taste. — The sense of taste is supposed to have its centre in close relation to that of smell, and, according to Ferrier, it is probably situated somewhere about the lo^^■er extremities of the temporo-sphenoidal lobes. The gustatory path crosses in the posterior part of the posterior segment of the internal capsule. Gowers thinks that taste-impressions reach the brain solely by the roots of the fifth nerve, and not through the glosso-pharyn- geal nerve. He admits, however, that the nerves of taste to the back part of the tongue may be distributed with the glosso- pharyngeal, reaching them through the otic ganglion by the small superficial petrosal and tympanic plexus. The centres which we have considered occupj^ parts of the non-excital)le cortex. This non-excitable area has T)een divided into fl) the parts behind and below the excitable cortex, as well as the convolutions on the median surface of the brain, except the marginal gyrus ; and (2) the frontal region anterior to the excitable area. We shall return, however, to the considera- tion of these later ; and for convenience' sake we shall now look at the construction of the apparatus by means of the working of wliicli mechanical movements are effected. Motor Nerves. — The course of the fibres which convej' impulses for motion is as follows : — The pj^raniidal tracts pass from the motor areas of the cortex through the A\-hite matter of the cerebrum to the internal capsule, where the fibres for the face and tongue occupy the knee of the capsule, those for the arm the anterior third of the ])osterior segment or liuib, whilst those for the leg occupy the middle third. They then pass beneath the optic thalamus to the crusta of the cerebral peduncle, which they enter and occupy its middle third ; the fibres for the face lying next to the middle line, then the fibres * Quain, op. cit., p. 160. MOTOR NERVES. 103 for the arm, and external to these the fibres for the leg. Their subsequent course is to the pons on the same side, where the fibres for the face and tongue cross to the nuclei of the facial and hypo-glossal nerves of the opposite side. The fibres for the arm and leg go to the medulla oblongata, where they form the anterior pyramids. Subsequently, the greater number cross at the decussation of the pyramids to form the crossed pyramidal tracts, or lateral columns of the opposite side ; whilst a lesser number continue on the same side as the direct pyramidal tracts.* The question as to whether there is ultimate crossing of the latter set of fibres need not detain us here. Accordina: to Melius t and Sherrington,:}: some fibres pass to the crossed pyramidal tract of same side. The pyramidal fibres are con- nected with multipolar nerve-cells of the grey matter of the spinal cord at successively lower levels, and it is from these multipolar nerve-cells that the anterior roots of the spinal nerves arise. A somewhat similar course is known to exist for some of the motor cranial nerves. After leaving the internal capsule and the crusta they pass across the middle line to their respective nuclei, from which fibres proceed to the muscles supplied by these nuclei. The excitable part of the cortex is, in the monkey, around the fissure of Rolando, and includes the ascending frontal and parietal convolutions with the parietal lobule, and the posterior parts of the three frontal convolutions, as well as the corres- ponding part of the marginal convolution on the median surface of the hemisphere. The exact localisation of the excitable areas of the cortex is of importance not only in determining the seat of discharging lesions, causing local epileptiform fits, but also in determining the possible rela- tions which exist between various psj^chic functions and their expression in motion. In brief, stimulation of certain parts of the excitable cortex is supposed to give rise to movements in their corresponding muscular areas. These relations may be tabulated as follows : — * Muratoff, " Xeurologisches Centralblatt," March, 1892 ; also " Archiv. fur Anatomie und Physiologie," 1893, Heft iii. t "Proc. Roy. Soc," 1894. t "Lancet," 1894. 104 SCHEME OF THE CENTRAL NERVOUS SYSTEM. In Monkey. Area stimulated. Part of marginal gyrus opposite to the ascending frontal convolution. Next to the preceding area, on the outer surface, the upper ends of the ascending frontal and parietal con- volutions as far out and down as tlie horizontal level of the superior frontal sulcus, and as far forwards as the ver- tical limit of the prfe-central sulcus. JResults of stimulation. Movements in limbs and trunk- muscles of the opposide side of the body (Horsley and Schafer). Movements in lower limb opposite side (Ferrier). Below this latter area, the ascending frontal and parietal convolutions down to the genu or bend in the fissure of Rolando ; bounded below by a line drawn from the upper end of the prte-central sulcus backwards through the genu of the Rolandic fissure to the anterior end of the intra-parietal sulcus, and in front by a line drawn from the prse-central sulcus upwards to the middle line. Below this latter area, a narrow strip of cortex. Below this area, and between the Rolandic fissure and tiie prfe-central sulcus. Round the lower end of the Rolandic fissure. Movements in upper limb. Between the inferior end of the Rolandic fissure and the fissure of Sylvius. In front of the latter area, and bounded below by the fissure of Sylvius, three small areas from behind forwards. Posterior part of third frontal convolu- tion (left side). Posterior part of three frontal convolu- tions in front of vertical limb of prte- central sulcus, and a line drawn between this and the middle line, {a) in the angle formed by the two limbs of this sulcus ; (J)) between the horizontal limb of this sulcus and the middle line ; (c) below the latter area. Closure of opposite eye-lids, and if the current is stronger, closure of eye-lids on same side (Horsley and Beevor). Elevation of the opposite angle of the mouth. Retraction of the angle of the op- posite side of the mouth. Bilateral movements of opening the mouth. Rhythmical movements of mastica- tion, swallowing, and adduction of vocal cords. Aphasia. (a) Synchronous movements of turning head and eyes to op- posite side ; (A) head tends to move without or before the eyes ; (c) synchronous movements of the eyes occur before or without the head. MOTOR NERVES. 105 Reference to Fig. 11 will show, that as we pass from the marginal gyrus along the fissure of Rolando, we meet with areas which represent a gradual increase in complexity of function. No sharp line of demarcation is possible, however, between these areas of representation. Horsley and Beevor have given the name of "border centres" to those places, stimulation of which causes combinations of movements. The same authors have found that the different segments of the limb have areas of representation ; those for the lower limb being (in the monkey) in the following order from before backwards — viz., hip, knee, ankle, and hallux ; whilst in the upper limb area they occur in the order from above doAvnwards Fig. 11. Diagram of Motor Akeas. {After Hornle!/ and Beevor.) — viz., shoulder, elbow, wrist, lingers, index finger, and thumb, the three first being most represented in front of the fissure of Rolando, while the three last are behind it (Beevor). We have, therefore, in the cortex cerebri some fairly definite areas which are apparently directly concerned with the reception of incoming stimuli, aiad others which are apparently concerned with outgoing impulses or motor stimuli. In addition to these areas, however, there are others, which, so far as we know at present, are non-excitable. Ferrier, Horsley, and Schilfer have removed that part of the cortex of the frontal lobe situated anterior to the areas which we have seen to be excitable, with 106 SCHEME OF THE CENTRAL NERVOUS SYSTEM. the result, that there were no observable sensory or motor symptoms ; moreover, there was little or no change observable in the mental condition. Ferrier noted a marked mental change when the cortex was stripped from this area on both sides of the brain, but Horsley and Schafer found no mental change whatsoever. We shall have occasion later to return to the question of the functions of this part of the brain, and of the possible relations it may hold to the rest of the cortex, so we now pass to the consideration of the arrangement of fibres, in the so-called '' projection systems." Projection Systems. — Meynert has described three such systems. The first projection system consists of fibres which lead to and from the cortex cerebri ; they pass in a radiate direction through the corona radiata, some traversing the basal ganglia, others forming connections with the cells of the central gi'ey matter. In addition, there are commissural fibres of the corpus callosum and the anterior commissure, which are supposed to connect the two hemispheres ; and connecting or associatiiKj fibres, which connect difterent areas of the same side with one another. Meynert regards the corona radiata as containing fibres from the corpus striatum, lenticular nucleus, optic thalamus, and corpora quadrigemina. The seconds iwojection system consists of fibres of great variation in length, which run in a longitudinal direction downwards to the central grey tube. Some of the fibres end in this central grey matter, while others pass to the level of the lowest spinal nerves. The fibres which descend from the caudate and lenticular nuclei pass through the crusta of the cerebral peduncle, and enter the medulla or pons (Flechsig). Those from the thalamus and corpora quadrigemina pass through the tegmentum to join others from the crusta in the spinal cord. Wernicke believes that the caudate and lenticular nuclei are independent, and that the radiate fibres from the corona radiata do not enter them. Fibres, however, may proceed from them to the crusta, to join those fibres coming from the thalamus and corpora quadrigemina. Meynert regards the latter set of fibres as lieing reflex channels, and he looks upon these regions of the brain as centres for certain extensive co-ordinated reflexes. PROJECTION SYSTEMS. 107 The third iwojection system consists of the sensory, and motor, peripheral nerves. In the medullary centre we have, there- fore, three systems of fibres — -viz., Projection-fibre, Commis- sural-fibre, and Association-fibre systems. The projection fibres are regarded as being direct pro- longations of the axis-cylinder processes of cells of the cortex. The commissural fibres, which connect the hemispheres, include, as before mentioned, the transverse fibres of the corpus callosum, and the fibres of the anterior commissure. The fibres of the corpus callosum come from the cells of the cortex direct, or they are collaterals derived from the projection system. Sherrington has demonstrated that not only does the anterior portion of the corpus callosum contain fibres from the frontal lobes, the middle from the middle lobes, and the pos- terior from the occipital lobes, but that there is also a tendency to scattering of fibres, so that not only similar but also dissimilar parts of the two hemispheres are connected through this commissure.* Hamilton states that some projection fibres also cross the callosum, and then turn downwards in the internal capsule. The anterior commissure is made up of fibres, which chiefly connect the temporal lobes of the two hemispheres. These fibres spread out into a fan-like arrangement in the temporal lobes. There are also some fibres which are thought to connect the olfactory tract of one side with the opposite hippocampal gyrus.! The association fibres vary considerably in length. The fihrice propruv (Meynert) are short fibres which pass below the grey matter at the bottom of the fissures, and serve to connect adjacent convolutions ; while the long fibres run free or are grouped into bundles in one of the following directions : — (1) a superior bundle runs below the grey matter of the cortex, serving to connect the frontal and occipital lobes, and the frontal and external part of the temporal lobe : (2) an inferior bundle runs a course near the outer wall of the posterior and inferior cornua of the lateral ventricle, and serves to con- nect the temporal and occipital lobes : (3) an anterior bundle * "Journal of Physiology," 1890. t " Archiv. fiir Psychatrie," 1878, vol. ix. 108 SCHEME OF THE CENTRAL NEEVOUS SYSTEM. passes across the bottom of the fissure of Sylvius, and connects the frontal, especially the third, Avith the temporal lobe and the anterior part of the limbic lobe : (4) the cingtilum forms the chief bundle of the gyrus fornicatus, its fibres pass from the anterior perforated space in front, above the transverse fibres of the corpus callosum, to curve round the splenium of the callosum behind, and to reach as far as the anterior extremity of the gyrus hippocampi. Some of the fibres diverge into the white matter of the hemispheres, and, according to Beevor,* they probably connect the hippocampal and callosal gyri with the cortex of the outer surface of the ^f'wpcfi/ii. Lose Fig. 12. s, Sbort association fibres connecting adjacent gyri ; J'.l.s. , fasciculus longitudinalis superior ; ci., cingiilum ; c.c, corpus callosum; f.p., fasciculus perpenrticularis ; /.L/., fasciculus longitiKlinalis inferior; fo., fornix ; f.i., fimbria; v.d'A., bundle of Vicq d'Azyr. (After Meynert.) hemispheres : (5) a perjoendiculdr bundle runs in front of the occipital lobe, and connects the inferior parietal lobule with the fusiform lobule : f (C) the fibres of the fimbria of the fornix connect the hippocampal region of the limbic lobe with the corpus albicans ; and, through the bundle of Vicq d'Azyr, with the thalamus opticus. • " Phil. Trans.," 1891. t Wernicke, " Lehrbucli der Gehirnkrankheiten," 1881, vol. i. CEREBRAL LOCALISATION. 10& Value of our knowledge of Cerebral Localisation. — Hitherto, the attempt to proceed beyond the objective evi- dences of the localisation of the motor and sensory functions, to the localisation of the parts of the brain subserving the sub- jective side of mental phenomena has been attended with verv great difficulty, and these subjective conditions still remain upon a most unsatisfactory basis — e.ij., in various morbid mental conditions, where the state of consciousness is more or less altered, it is difficult to explain or localise the seat of the lesion when there is no evidence of paralysis of the motor or sensor}^ functions, and vice versa. The nearest approach to the connecting link between the seat of intellect and the sensory and motor functions has been made by the minute study of such conditions as aphasia, and of this relationship Bastian has formulated (provisionally) a general law as a working hj-po- thesis — viz., " The tendency to mental impairment with aphasia, and the degree of such impairment will, other things being equal, increase as the lesions of the left hemi- sphere, \^'hich produce aphasia, recede in site from the third frontal convolution, and approach the occipital lobe." The exact localisation of the excitable coi'tex is of the highest value in determining accurately the seat of discharging lesions, causing epileptiform fits, etc., but no matter how exact the study, or how accurate the inferences drawn therefrom may be, such data still leave us far from the localisation of mental phenomena. Let us now look more carefully at some of the facts before us, and let us endeavour to arrive at some conclusion as to how far we are really able to localise even the simplest mental state. (1) Phrenolo(jical ma/pjmuj out has proved of no value- hitherto, and we are forced to acknowledge that phrenologists have not shown us anything that is vei'ifiable. (2) Experimental research has done much to determine certain physical relationships between cortical areas and afferent and efferent impulses. (3) Comparative anatomy has also done much by demonstrat- ing that differences of brain structure coexist with differences of mental faculty in races and species of animals. Meynert gives three anatomical facts which render a functional differentiation of the various cortical regions highly probable : (a) the develop- no SCHEME OF THE CENTRAL NERVOUS SYSTEM. ment of the olfactory lobe in different animals associated with the amount of use of the olfactory sense ; (h) the difference in the relation between the median and the convex surfaces of the cortex in animals with strongly-developed olfactory lobes, and in man ; (c) in the human brain the walls of the Sylvian fissure, are most highly developed. Man excels in the develop- ment of the regions associated with speech, and in the number of convolutions belonging to these regions, as animals with highly-developed olfactory lobes excel in regard to the size of these lobes. Therefore, he believes that the evolution of certain psychical functions goes hand in hand with a proportionate development of certain regions of the cortex. Other morpho- logical points would apparently lead to the same view — e.g., the quantitative differences in the brain trunks both in man and in animals dependent upon quantitative variations in the different parts of the forebrain, giving the idea of a harmonious dependence between the form of the brain-trunk structure and the quantitative development of the forebrain. (4) Morhid anatomy, or the noting of the effects of lesions in different parts of the brain. Kirchhoff * asks the question, ■' To what extent have focal diseases aided in our knowledge of the location of mental disturbances ? " If we take into account only the lesions which interrupt the various conduction systems, we do not gain much knowledge as to the centres which are probably affected. Of the basal ganglia, the optic thalamus would appear to be more closely connected with the mental functions than the corpus striatum ; inasmuch as the former alone undergoes atrophy in congenital absence of the cerebral hemispheres. Kirchhoff believes that the disturbance in the intellectual development of individuals, in whom the corpus callosum is absent, or only very small, indicates that the higher mental processes are not dependent upon the frontal brain alone, for in these cases the occipital lobes are mainly atrophied. In some idiots, also, who have imperfect development of the brain as a whole, it is impossible to localise satisfactorily. Nor does he admit of any further conclusion being drawn from the study of irregular development in the cortical layers, unless the area so affected is circumscribed. " For example," he says, " in a * " Handbook of Insanity," p. 9. LOCALISATION OF THE MENTAL FACULTIES. Ill few idiots the frontal lobes contained onl}^ very few pyramidal cells, which were distributed irregularly, so that it was almost impossible to distinguish the layers." In these cases the im- perfect mental development may be attributed to the imperfect development of the frontal cortex. Localisation of the Mental Faculties. — In the attempt to localise activities of the mind, some assert, that each of the ultimate microscopic elements of the grey substance (ganglion-cell) represents a distinct psychical element (sensa- tion) ; others regard the brain as acting in its entirety, or at least through large areas. Before granting that the mind has its seat in the brain at all, let us look at some of the reasons which have led to this conclusion. (1) The brain («) is an indispensable medium between certain changes in the peripheral parts of the body and corresponding changes in the states of consciousness ; {b) it serves as a basis for the execution of the ideas and volitions of the mind. If nothing takes place here, nothing at the periphery of the body will come from the volitions ; if anything wrong takes place here, all that goes on at the periphery will be wrong, and the mind will not get its volition executed, (c) The brain seems to serve as the special physical basis of the ideas and volitions of motion themselves. After experience in moving a particular member of the body has once been gained, that member may be lost ; and yet, if the proper areas of the brain remain unimpaired, the ideas, feelings, and volitions connected with the movement of the lost member will still arise in the mind. The man whose leg or arm has been amputated can still feel it, can form the image of how it should be moved to be in this position or in that, and even will to have it moved. The leg is not, then, the organ of these ideas, feelings, and volitions (Ladd). (2) If the cerebral hemispheres of animals ai'e removed various effects are produced. Ferrier says there is little difference from the normal mental condition. Vulpian* found, that not only may a fish be urged to move by bringing an object before its eyes, but it would also avoid obstacles as if still possessed of a sense of vision. Steinerf said that the only difference was a greater tendency to impulsiveness, and less caution in those which had been operated upon ; further, not only do they see their food, but discriminate between the different kinds of food. * " Systeme Nerveux," p. 669. t " Die Functionen des Centralnervensystems, Zweite Abtheilung," Die l^'ische, 1888. 112 SCHEME OF THE CENTRAL NERVOUS SYSTEM. It is often difficult, so far as their movements and response to peri- pheral stimuli are concerned, to distinguish between a normal and a brainless frog. Terrier believes that, if the observations of Goltz and Steiner are correct, the principal points of distinction between the brainless and the normal frog— namely, the absence of spontaneity and the power to feed itself, which are said especially to characterise the former — are no longer capable of being upheld, and that the brainless frog behaves precisely like the brainless fish. Longet believed that the removal of the cerebral hemispheres anni- hilated only perception proper, as distinct from crude or brute sensation, which had its centre in the mesencephalic ganglia.* Ferrier says that, if the results obtained by Schrader are correct, we must class" birds with fishes and frogs, which retain their sense of sight and guide their movements accordingly, even when the cerebral hemispheres are removed. In animals generally, there are great variations, according to their lowness in the scale. Adaptive reactions appear to be better organised in the mesencephalic and spinal centres in fishes, frogs, and pigeons than in the lower mammals, and least of all in monkeys and man. Can we infer, from the adaptive actions of the lower centimes, that there is intelligence at the root of those actions ? Ferrier believes that facts lead to the conclusion that between the simplest reflex action and the highest act of intelligence there is no essential difference, the one passes by insensible gradations into the other. He says we can infer only ; we can prove nothing. We can say that the activity of the lower centres does not affect the consciousness — as in lesion of the internal capsule, when the sensory tracts are cut off from their cortical connec- tions. The individual has absolutely no consciousness of impressions made upon his organs of sense, so that we may conclude that, in man at least, states of consciousness are indissolubly connected with the activity of the cerebral hemispheres. Further, says Ferrier, " one may remove, anteriorly or posteriorly, from above, or from the side, a considerable portion of the cereln-al lobes without destroying their functions. Even a small portion of these lobes, therefore, suffices for the exercise of their functions. In proportion to the extent of the removal, all the functions ^-.ecorae impaired and gradually fail ; and beyond certain limits they are altogether annihilated. The cerebral lobes, therefore, co-operate as a whole in the full and complete exercise of their functions. Finally, when one form of perception is lost, all are lost; when one faculty disappears, all disappear. There are, therefore, no special seats, either of special faculties or special perceptions. The faculty of perceiving, judging, and willing one thing resides in the same region as that of perceiving, judging, and willing another; consequently, this faculty, essentially one, resides essentially in one organ." * Flourens, " Systeme Nerveux," 1842. LOCALISATION OF THE MENTAL FACULTIES. 113 Certain areas of the cerebral cortex do appear to be con- cerned with the execution of certain functions of the mind. AVe cannot regard the mind, in its special relation to the brain, as limited to any point or small area of the cerebral cortex. Nearly all observers are agreed that considerable pai-ts of the cortex can be destroyed without impairment of any of the special functions or faculties of mind. In fact, there is nothing to indicate that the mind depends upon cerebral activities concentrated in any one minute circumscribed spot. Goltz,* jMunk, and Flourens agree in thinking that the most important cerebral functions, from which we conclude mental functions, cannot depend on definite sections of the cerebrum. If we accept the doctrines of the more recent English school — that individual sensations or ideas exist only as mem- bers of a connected, conscious series, and that consciousness, therefore, can never be conceived as a mere sum or mere product ; f and if we believe with Hume that consciousness is a mere succession of ideas without inner bond or connection, or that it is the series of our actual sensations (John Stuart Mill), it may be thought possible that there are individual nervous elements which possess isolated and distinct forms of con- sciousness. From pathological conditions we do not appear to obtain evidences which may be termed conclusive ; nor do such evidences prove to us that consciousness is confined to any supreme part of the cerebral cortex. Gowersj: says. "• With the much disputed question of the relation of mind to brain, the physician has nothing to do. It is enough for him to recognise that mental manifestations and cerebral activity invariably coincide, and that the character of cerebral pro- cesses in some way determines mental states. In the study of diseases of the brain we are concerned only with cerebral processes. Unfortunately, however, the chief terms available are those of psychology, and Ave are obliged, therefore, to speak of mental processes when all that we need speak of, and are. indeed, justified in speaking of, are cerebral processes. How- * •• Pfiiiger's Archiv.," xxvi. p. 35. t Hoffding, "Den engelske Filosofi i vor Tid,"' Copenhagen, 1874. J " Diseases of the Nervous System," p. 98. 114 SCHEME OF THE CENTRAL NERVOUS SYSTEM. ever undesirable such a contusion may be, it is practically unavoidable.* What are the cerebral processes which in- variably coincide with mental manifestations? Can we imagine any one cerebral process, or set of processes, which coincide with any one mental state or group of mental states ? Until we are in a position to answer these questions, it is obvious that we are, in reality, not in a position to speak of mental processes solely as cerebral processes. Nor do we know where to look for the junction of these cerebral processes with their "■ coinci- dental " mental processes. The pathological data with which we are furnished, ai'e, however, by no means to be ignored. Cases in which there has been complete destruction of one cerebral hemisphere, without mental disturbance, have suggested the possibility of vicarious activity of the other half of the brain, provided that both halves possess originally the capacity for exercis- ing the same function. Kirchhoif regards this question of the co-ordinate value of the liemisphere as of the highest importance in the examination of the site of individual func- tions. Similarly, in aphasic conditions, the consideration of the physiological variations in the course of speech conception, is of manifest importance. Further, although (as we shall see presentlj^) we are iiot in a position to say that conscious movements originate in the motor centres ; these centres, nevertheless, constitute stations, or connecting- links, for the transmission of such processes ; hence, witli disease or destruction of these areas, there is a tendency to restriction of the objective manifestations of consciousness. In the same way, affections of the so-called sensorj^ areas may restrict or modify the amount or quality of sensory representa- tions in consciousness. In fact, although we cannot bring ])athological processes into direct apposition to morbid mental processes, we can conceive, on a k^wer platform, various con- ditions of disease which lead, in an unknown way, to restric- tions and variations in the phenomena contained in that highest of all platforms — the seat of hiiman consciousness. Speaking of the difficulties of nerve-conduction through the * The facts with which the alienist has to deal are in the main psychic facts. LOCALISATION OF THE MENTAL FACULTIES. 115 network of fibres in tlie grej^ substances, Meynert points out, that we may infer that this enlarged surface will be able to per- form a number of totally independent functions ; that a sensory perception, for instance, need not give rise immediately to a motor act. Every spinal cord segment embraces the whole of the grey substance, Avhereas sections through the cortex contain but a small portion of the cortical grey. This distribution of grey substance will naturally prevent the entire cortex from acting to one single end, while it favours the isolated action of various cortical regions. Irradiation of functions is facilitated in the grey substance of the spinal cord, and rendered difficult in that of the cortex. Further, pui-ely morphological data and a single pathological anatomical fact will enable us to determine which regions of the cortex, in the probable division of labour, take upon themselves centrifugal functions in the •sense applied in Bell's law. The expression " irradiation of fiindioiis''' at once suggests a clue to our actual pathological posi- tion, and we are forced to confess, that pathology, so far, has truh- served to demonstrate the implication by disease of the sites concerned Avith the irradiation of functions, and not of the .actual ultimate site of consciousness. Our position, therefore, is only a step higher in the confirmation of Bell's law. of the conduction of nerve-force in a centripetal direction through the posterior, and in a centrifugal direction through the anterior spinal roots. In our attempt to find the site which is concerned directly with consciousness, we have explored various sensory and motor regions from an objective and physiological point of view. Before leaving these regions, however, let us really make sure that we are justified in concluding that conscious- ness is not ultimately determined in this sensory or motor platform — i.e., can we find any reason which would justify the belief that any subjective condition or state of conscious- ness may arise directly from the objective functioning of the iso-called areas of sensation and motion without the aid or •collaboration of other still higher centres? First of all, let us try to answer the question. Are the so-called " motor centres " and '' sensory centres " really the centres for pure motor and sensory events ? or, as put by. Waller, •' Have we reached 116 SCHEME OE THE CENTRAL NERVOUS SYSTEM. any true dead end to knowledge in the conclusion that the cerebral cortex contains ' sensory centres ' and ' motor centres,' and, if so, what signification do Ave attach to these final terms?"* On the question as to whether excitation-effects are caused by direct action upon particiilar centres in which the voluntary motor impulse arises, or whether they are attributable to an excitation of subjacent fibres, or Avhether any third possibility exists? Hitzigt says, "Even if we assume as proved that the movements in (juestion are liberated by the ganglionic substance — and it is not proved — this would not be enough to prove that with these movements which are liberated by the internal event, that precise portion of the cortex furnishes the substratum of the first outward step in the series beginning with the origination of a sense-impression, and finding a temporary end in the expression of Avill evidenced as muscular movement. " It is, on the otlier hand, far from inconceivable — and the notion is favoured by our knowledge of the anastomotic structure of these parts — that that portion of the brain which includes tlie birthplace of a will to move is of another, or perhaps of a more complex nature, and that the parts which we have called centres only constitute agencies, ex- changes, in which an arrangement of muscular movements occurs, similar to that effected through the grey matter of the spinal cord and basal ganglia, but more purposeful." From experiments made upon two dogs, from which por- tions of the motor areas -vA'ere removed, Hitzig concluded that the animals in question, after the operation, had only an im- perfect knowledge of the state of the affected limb, and that they had lost the power of forming complete representations of it. " Still," he says, " it is clear that very exact representations of the state of muscle must be produced — as we learn from these very images of movement — and it is equally clear that these images are attributable chiefly to the perception of the muscular stage and only in minor degree to joints, skin, etc., this Ave learn from the Avell-knoAvn illusions of raoA'eraents occurring in the pai'alysis of the ocular muscles. " If, nevertheless, our representations of the muscular state of our own body do not overstep the threshold of distinct consciousness, and thus enable us to see into the true nature of the process, Ave must attribute this failure to a very general laAv. AVe are able to distinguish * "Brain," 1892, p. 330. t "IJrain," 1892, p. 135. LOCALISATION OF THE MENTAL FACULTIES. 117 the state of particular organs only in so far as is necessary and sufficient for their use in the uninterrupted maintenance of their functions. " But within such limits the apprehension of these mainly uncon- scious representations of each particular phase of movement, constitutes one of the necessary conditions of a normal progress of its succeeding phase ; subsequently (considering apparent muscular repose as a phase of movement), one must recognise that muscular states in general are among the various causes that guide the organism in its voluntary movements, and that regulate these movements. Let us assume an entire absence of all other sensory stimuli and perceptions, so that we have to do with a simple motor machine of such a kind, set in motion by the muscular impulse, we may then very well imagine it as sufficient for the execution of purposive movements. " We have recognised in the above-described portions of the cortex an organ, the function of which coincides with that aspect of the psychical phenomenon that we have been considering, and I do not see the necessity for admitting that will, as such, involves a specific and motor organ." Munk * says, *'Just as the cortex of the occipital lobes stands in relation to vision, and that of the temporal lobes to hearing, so the cortex of the parietal area stands in relation to common sensation (Gef iihlsinn) : in this, as in the other cases, we have the locus where perception is consummated, and where rei^resentations — the memory images of perceptions — have their seat. Let it be clearly understood, however, that it is not sensation of the skin only that is here in (juestion, but sensation in its broadest sense — the sensation of the whole body." Further, he asks, " What are the organs, of whicli the modifications can reach consciousness as neural sensations ? These organs are : the subcortical ganglia or centres in brain and cord, that invoke movements. As in the infancy of the animal, the representations of movement are developed from its first purely reflex movements ; as in the adult animal, the representations of movements of a part of the body can still arise in its sensory area, even if {e.g., in locomotion) this sensory area is not actually participating in the accomplishment of such move- ments ; as, finally, the representations of movement lost in consequence of cortical extirpation in a given part of the sensory area, may be formed out of the reflex and automatic movements of the affected part, it cannot but be that fibres ascend to the cerebral cortex from sub- cortical motor centres or ganglia, as well as from tlie skin and from the muscles — the fibres that subserve cortical perception of these sub- cortical centres. " Our neural sensations are indeed, for the present, to be distinguished from what has hitherto very generally received the name of neural sensation (Innervationsgefuhl) — from the 'perception of the intensity of voluntary effort in connection Avith voluntary movement,' 'will,' * Du Bois-Eeymond, " Arcliiv.,"' 1878, p. 162. 118 SCHEME OF THE CENTRAL NERVOUS SYSTEM. ' voluntary movement,' with seat and origin in the cerebral cortex. ai*e indeed very convenient, and may, therefore, also be, valid expres- sions, but they are destitute of a phenomenal physiological substratum. All we know of the cerebral cortex is, that it is the place of perceptions and the seat of representations. Beyond this, it is merely admissible to assume, as has been assumed by Meynert on somewhat different data, and by Wernicke, that representations of movement are the causes of so-called voluntary movements ; that with the production of such a representation to a given degree (and, indeed, with a production via sensation, not via its ordinary constituent sensations) eo ipso the corresponding movement is elicited ; and that the greater its forma- tive representation the greater the resultant movement. The ' percep- tion of voluntary effort, in connection with voluntary movement,' might, indeed, be the attribute of a representation of movement ; a true perception might still obtain only indirectly, (juite independently of the ' will,' and the percept would then be nothing but the neural sensation in the sense just set forth." Waller adopts the view that every centre must be sensori- motor, and in the two different components of the double term he does not recognise any phenomenal division of the central process into sensory and motor. He says. '^Between centripetal and centrifugal impulses I see a single psychical process, one and indivisible ; to call it sensory or to call it motor, or even to call it sensori-motor, are, to my thinking, imperfectly and improperly to designate it by more or less subjective terms, with more or less obstructive connotations. All that I can recognise in the notion of a centre is an organ of elaboration receiving and giving out impulses. By the term motor I denote that it emits but fail to denote that it receives ; by the term sensory I denote that it receives (and imply that it feels) and fail to denote that it emits impulses ; by the term sensori-motor I denote reception, 'feeling,' and emission. All these meanings when closely analysed are illegitimate, and convey too little or too much. Experimentally I may not predicate ' feeling ' of any centre, but only of the hypothetical ego, I may only infer from visible movements that other animals ' feel,' and that sensations similar to my own are associated with the activity of certain centres. " I picture a wave of change passing tlu'ough a cell, but do not know at what transverse section of the wave to label it 'motor' or 'sensory.' The property of cortical grey matter is senso-motivity ; the most typica so-called motor cortex is sen.so-motor ; the most typical so-called sensory cortex is senso-motor. " A central process is not sensory or motor, but senso-motor (in a guarded sense), and a centre is an ' organ of return of action.' " By those who make a distinction and contrast between a motor and sensory process, the motor idea is a mental picture of viovements about COXCLUSIONS. 119 to be made, the kinsesthetic idea is a mental picture of movements just made. The motor idea is considered as an antecedent to motion, the sensory idea as its consequent. " It is not possible to distinguish a ' kinsesthetic ' image of past movements from a ' motor ' image of impending movements. The tvro words denote one thing. Nevertheless, "we can and do recognise in the use of the M'ord senso-motor, which connotes the notion that the centripetal generates the centrifugal phenomenon, the principle that phenomena have generators and consequent antecedents : we are reminded by the word that a centre is an organ of return of action and that the type of all motor action is a reflex act. This principle is recognised by all leading workers and thinkers — by Hitzig, in his con- ception that the motor area of the cortex is a ' muscular sense ' area : by Munk, in his conception that it is the motor ' Fiihlsphare ' ; by Bastian, in his conception that it is the centre of ' kinsesthetic' impres- sions. These three conceptions are but one and the same concei^tion^ which I most explicitly and unreservedly accept as a fundamental article of thought.'' Waller points out that his remarks c]o not directly involve any question of actual localisation. Its main arguments are equally applicable, whether senso-motility be the property of the entire cortex or of only its Rolandic area, whether we admit motor and sensory centres as taught by Hitzig and by Ferrier, or the cortical map of Munk, or indiiference of function in the unrestricted sense of Flourens, or in the restricted sense of Goltz. In whatever light Waller looks upon this question, his remarks — '•' Thought of movement is memory of movement, or, more generally, the thought is the remembered. An impulse, an intention, a resolu- tion ; a prayer is a more and more concentrated act of attention, of memory, of thought. An identical neural process is the essential phenomenon wrapped up and presented in these very different words : will, attention, memory, belief, thought '' — would appear to infer such functional attributes to the Rolandic area of the cerebral cortex— i.e., to a region essentially sensori-motor in function. He also disagrees with the exclusion of the motor zone from the sphere of consciousness, as enunciated by James, Bastian, Ferrier, Gotch, and Horsley. To James's comparison of the motor area to the mouth of a funnel (through wliich pour outgoing impulses, caused by incoming impulses) he also takes exception, at least, in so far as the theory holds that the functions of the structures at the mouth of this funnel may be only those of consciousness of the kinaesthetic ideas and sensations, and that this consciousness accompanies the rise in activity of them rather than its discharge. To James's hypothesis that these paths all run one way — that is, from "sensory" cells into "motor" cells, and from 120 SCHEME OF THE CENTRAL NERVOUS SYSTEM. motor cells into muscles, without ever taking the reverse direction — he agrees ; -whilst with the statement, '• All cells are ' motor : ' we simph' call those of the Rolandic region — those nearest the mouth of the funnel — the motor cells par excellence,'' he agrees, "most unre- servedly." Further, he says, " Any motor or discharging centre must also be a ' sensory ' or receiving centre ; it must be excited as well as excite. Any 'sensory' centre must also be motor, directly or indirectly ; else we could have no objective tokens of sensation ; every centre, whether called motor or sensory, is terminus ad quern as well as terminus a quo.' Let us add to these views those of Meynert — viz., " Actual sensation is developed by the evolution of equally unknown external forces, which we must suppose differ very materially from one another. Nerves and nerve-cells possess no motor power. Indeed, there is nothing more certain about the functions of the cerebral organism, than that the centripetal sensory nerves are the keys which wind up the mechanism connected with the muscles, and excite the latter to action. "A varying functional energ}^ of brain-cells, according to the special organ of sense with which they may be connected, is quite indemon- strable, since we are acquainted with the physiological conditions favourable to the action of external forces, and can prove easily enough that it devolves upon the terminal organs of the nerves to meet these conditions. " Specific energies, therefore, depend altogether upon the peculiari- ties of the end organs, and setisitiveness is the only specific property of brain-cells." Conclusions. — AVhat are ^\■e to iearn from these con- troversies ? Are we. after all, any the bettei' able to come to any conclusion as to whether consciousness; exists, as such, in- the areas we have considered? or is some higher area essential to the psychical events ? If \\e look upon the so-called sensory and motor areas as containing the structiires which have sensitive- ness (by this we do not imply any psychical correlate or state of consciousness) and the power of furthering, or even adapting, forces in a determinate direction ; and, if Ave regard this physical apparatus more as a further advancement in com- plexity of the fundamental reflex power, it is obvious that the areas of such activities are only in a degree more closely approximated to the actual site of consciousness than other centres on a lower level in the cerebro-spinal SAStem. Yrom experimental investigations upon animals, it may be gathered that extirjiation of a certain region, or regions, is followed by total loss of sensori-motor functions, as viewed objectively, but CONCLUSIONS. 121 this is no guarantee that subjective psychical conditions are not still present. On the other hand, just as we may have couipli- cated adaptive movements of exceeding fitness performed by the animal M'hose cerebrum has been destroyed, so we ma}- have complicated mechanical, and even, apparently, intellectual per- formances brought about on a higher level without the slight- est evidence of any conscious psychical correlate. By this is meant, that fitness of reaction is no sure evidence of immediate conscious guidance. The functions of the so-called sensori-motor areas, therefore, can furnish us with no more proofs of their being ultimately concerned with consciousness, than can the activities of lower centres which possess the same fundamental properties, although developed in a lesser degree. The theory of reflex action, as first applied to explain cere- bral processes b}^ Laycock, has been very generally accepted. He did not, however, attempt to explain why some of the most complicated cortical processes were attended by consciousness and others not. He viewed the objective and subjective phenomena as correlated in some, but he did not seek to establish a direct or local correlation of the phenomena in a definite area, nor did he seek to explain either phenomenon in the terms of the other. The well-known views of Hughlings- Jackson, that the sensori-motor apparatus of the cortex is re-represented in other centres higher in the scale than the physiological sensory and motor areas in the cortex, find the most favour with those who have obtained an intelligent grasp of this subject ; and, if we accept his view, that mental opera- tions are simply the subjective accompaniments of sensori-motor processes, we do not, at the same time, in any way bind our- selves to the possibly erroneous conception that such subjective accompaniments are in immediate local juxtaposition to the physical sensori-motor processes. We have an abundance of examples of complex reactions with ^hich no psychical correlate is apparent; and it is readily conceivable, that jvist as the nervous apparatus of lower centres is characterised by its sensitiveness and tendency to propagate its functions in a fit and appropriate direction, so the mechanism of the sensori-motor regions is characterised by its still more highly- developed sensitiveness and tendency to react to special stimiTli 122 SCHEME OF THE CENTRAL NERVOUS SYSTEM. conveyed throngh the medium of the special senses. On this assumption, and on this only, can we seek an explanation of many morbid objective manifestations as seen in the insane. In the early stages of the general paralj'tic, the occurrence of paralysis of his sensori-motor apparatus, as viewed by us objectiveh^, without implication of the consciousness or totality of his mental being, as viewed by him subjectively ; or in the acTite maniac, \\'hose sensori-motor apparatus furnishes us with objective manifestations of its abnormal activity ; or, again, in the active ph^^sical phenomena of sleep, epilepsy, and hj^pnotism : all these may be explained from a sensory-motor point of view, and without any obvious psychical concomitance. It is characteristic of the human consciousness, that it exists as such over and above all physical processes ; and, as yet, we are far from the possession of one fact, nay even one valid argument, in support of the conception, that the mind has its ultimate dwelling place in any one definite structure contained within the so-called sensori-motor regions of the cerebral cortex. When we discuss the questions as to whether revived images are gathered together into a special ideational centre, or whether they are merely taken cognizance of by the intelligence while remaining in their own situations, we shall see that the evidence stands in favour of the latter view. Some observers advocate that the intelligence is more especially con- nected with the superficial layers of the cortex ; but even this supposition is not supported b}^ evidence which can be regarded as conclusive. CHAPTEE lY. Localisation of the Mental Faculties — {continued). Sensory and Motor Areas subserve Mental Events — Localisation — Diffuse Localisation — Indifferentism — The Frontal Lobe — Intelligence not limited to Local Areas— Ilatiocinative Theories : Neural Inference Scheme of Ilughlings-Jackson ; Meynert's View of the Forebrain ; Wallers View, based upon Psychological Inference — Value of the Logical Mode of symbolising ^^eural Inference — Prsefrontal Lobes : Experimental Researches ; Patho- logical Evidences — Consciousness pertaining to Lower Centres — Local Memories — Subjectivity of the Mind — Objective Contents of Consciousness — Specific Functions of Xerve-Cells — Wallerian Scheme of the Four li's — Specific Quantifications of Motion — Negative Value of Physical Formulae — The Doctrine of "Invari- able Concomitance." At the close of the preceding chapter we stated that the per- ception of different sensations was not proved to be consummated within definite parts of the so-called sensori-motor areas. We mentioned, for the purposes of the student, the hypothesis of Hughlings-Jackson, and others, that in addition to the regions which have been defined as sensory and motor, there may be other and higher motor as well as sensory centres, within M'hicli all the motor and sensory functions are again repre- sented, and which form the substrata of the higher mental functions. This hypothesis, according to Ferrier, receives no confirmation from the facts of experiment ; nor does he regard it as at all necessary to explain the facts of normal or abnormal mentation. " AVe have in the sensory and motor centres of the cortex the substrata of the respective forms of sensory per- ception and ideation, and of the individual acts of volition, simple and compound, as well as of the feelings associated with 124 LOCALISATION OF THE MENTAL FACULTIES. their activity. It seems more reasonable to suppose that there may be higher and lower degrees of complexity or evolution in the same centres, than to assume the separate existence of more highly evolved centres, for which no evidence is obtained by the results of experimental research.''* Of this latter view no criticism is necessar}^ for it has not yet been proved that a centre for sensation and another for motion exists in the cortex ; and even though such centres did exist, we are very far from forming any conception as to tJie actual substrata of the resj^ective forms of sensory perception and ideation, arid of the individual acts of volition. We are, to a limited extent, cognisant of the physical conformation of the brain structures ; we know that there are paths of conduction for stimuli of various kinds, and We know that stimuli do pass along those paths and may be reflected in their course by structural realities, but beyond this we can conceive no inti- mate or ultimate substratum which directly serves conscious- ness. In fact, when we speak of the substrata of perception, ideation, and volition, as applied to the cerebral cortex, we can only realise, that we have advanced one step onward in our search for the structures which are immediately concerned with modes of consciousness, and that we are still on a level which offers little or no clue to the whereabouts of what we seek. The words of Herbert Spencerf — viz., "Whoever calmly considers the question cannot long resist the conviction that different parts of the cerebrum must, in some n-ay or other, subserve different kinds of mental action " — contain the pith of our knowledge of the whole question. The different parts of the cerebrum, as well as the whole physical organism, do subserve different kinds of mental action, but the}^ only sidj- serve, and we cannot as yet determine where or how the different kinds of mental action are ultimately served. Our position, in regard to the areas we have already investigated, therefore, is this, thei/, in some ira.ij or other, subserve the different hinds of mental a,ction. Further, Herbert Spencer says, " Local- isation of function is the law of all organisation whatever ; and it would be marvellous were there here an exception. * I'errier, "Cerebral Localisation," 2nd edit. p. 460. t "Principles of Psychology," 1870. CONSCIOUSNESS SUBSERVED. 125 Either there is some arrangement, some organisation in the cerebrum, or there is none. If there is no organisation the cerebrum is a chaotic mass of fibres, incapable of performing any orderly action. If there is some organisation it must con- sist in that same ' physiological division of labour,' in which all organisation consists ; and there is no division of labour, physiological or other, but what involves the concenti'ation of special kinds of activity in special places." An analysis of this statement in no way invalidates, or tends to check, the course of our thoughts. It involves both phj'sical and mental activities. Of the attempts to localise physiological activities we have onl}- to mention those of Ferrier, Schiifer, Horsley, Beevor, Charcot, Dejerine, Goltz, Wundt, Munk, Hitzig, SchifF, Bastian, Hubnoff*, Heidenheim, and others ; and from the results of their labours \ve cannot but recognise the law of the tendency to local differentiation of physical activities. When, however, we pass from the objective manifestations of these activities, and en- deavour to superimpose upon them various psychical states, we almost immediately get beyond oiir depth, and flounder amidst all sorts of conjectures and hypotheses. These hypotheses may be ranged under two classes — viz., (1) those which favour the view of localisation ; and (2) those which support the idea of diffusion of function ("diffuse localisation," or " indifFerentism"). But, the student will ask. Are we not still upon too low a plat- form of our organisation to entertain, for the present, such questions ? We are on the platform of the so-called sensory and motor centres; we are dealing with the physical substratum (so far as we know it) of the special senses ; and we are sur- veying the site which we have already granted, " in some way or other, subserves " consciousness. What we have now to decide is, do the elements of these physical siibstrata directly and within their own domain serve conscioiisness with the phenomena of sensation ? or do the}^ sub- serve it b}' a furtherance or propagation of their physical con- ditions to other regions where their activities are ultimately correlated with consciousness '? Herbert Spencer advocates, that a perception can have, in a nerve-centre, no definite local- isation, but only a diffuse localisation. No one excited fibre or cell produces consciousness of an external object: the conscious- 126 LOCALISATION OF THE MENTAL FACULTIES. ness of such external object implies excitement of a plexns of fibres and cells.* Wimdt objects to the view that sensations take place in the separate areas which are now regarded as sensory centres, inasmuch as such a belief would countenance the old phrenological faculty scheme. His doctrine of a frontal organ of apperception might appear to receive ample confirma- tion from the experiments of Ferrier, and from the reasonings of Hughlings-Jackson. Let us, therefore, go elsewhere in our search for some more highlj^ evolved substratum, than that of the chaotic mass of tracts and junctions contained within, what we term, the sensory and motor areas. The exclusion of the motor zone from the sphere of con- sciousness — enunciated b}^ James, and approved of b}^ Bastian. Ferrier, Gotch, and Horsley — has been objected to by Waller. The supposition that consciousness accompanies the rise rather than the discharge of activity in these regions in no way implies that the sphere of consciousness exists actually in them. The consciousness accompanying their activities is to be regarded as a collateral manifestation of the activities pro- pagated in some unknown way from these regions to other regions which are more directly concerned with the phenomena of consciousness. That is to say, we have not, as yet, arrived at the conclusion that there exists a more highly evolved centre, Avith the activities of which the respective forms of sensory perception and ideation, the individual acts of volition, simple and compound, and the feelings, are more directly associated. It does, indeed, seem reasonable to assume that there may })e higher and lower degrees of complexity of evohition in the nervous structures ; but we have, as yet, no conclusive proofs, eitlier that the various degrees of evolution occur in the same centres, or that there exist separate or more highlj^-evolved centres for the physical correlates of mentation. The frontal lobe contains a non-excitable area of cortex, which is situated in front of the area for the representation of the head and ej^es, and. in the monke}', is bounded posteriorly by a vertical line drawn through the anterior end of the huri/.ontal limb of the pra3central sulcus, from the median line down to a point a few millimetres in front of the anterior end * "Principles of Psych.," 2nd edit. 1870, p. 562. THE FRONTAL LOBE. 127 of the fissure of Sylvius.* This part of the brain is considered by most investigators to be the seat of the highest mental pro- cesses. Meynert believes that within the forehrain sensitiveness is converted into actual sensation. "The relation of the forebrain to the other parts of cerebral mechanism is easily understood. To this end we may recall the structure of the retina, which constitutes a hollow into which the visual rays from the external world are, as it were, entrapped. And, in the same way, we may look upon each half of the cortex of the forebrain as a concave organ, duplicated in parts, enveloping all the nerve-tracts, which conduct to it the impressions from the outer world. In this organ these impressions are converted into the phenomena of sensation. In assimilating totally unknown physical impulses, the cerebral cortex — a complicated protoplasmic structui*e — resembles the protoplasm of the primitive amoeba, which can transform itself into a hollow mass, and can thus encircle any body which it wishes to assimilate. Just as the mollusca possess tentacles, which they pro- trude toward the outer world, and claws, by means of which they take possession of their booty, so this complicated protoplasmic organism — the prosencephalic cortex — possesses centripetally-conducting processes — the sensory iibres of the nervous system — which we may consider its tentacles, and motor fibres, which are its claws. The remainder of the body, with its sensitive surfaces, its muscles, and the skeleton to which these muscles are attached, serves to sustain these tentacles and claws, which enable the forebrain to receive the images of the external world, and to react upon the latter." Munk regards the entire frontal lobe as a sensory sphere ; and others have pronounced the frontal region to be the exclusive seat of intelligence. Meynert corroborates the view of Munk, and adds, that consciousness, and intelligence also, which are evolved in the forebrain, depend upon a mechanism, the minute details of which, if understood, would enable us to restrict intelligence to the forebrain. From the experimental investigations of physiologists, we are led to believe that Avhen the forebrain is extirpated, there is serious impairment of the intelligence of the animal. Goltz. in particular, has demonstrated that the loss of only a few grammes of substance of the frontal lobes of dogs was suffi- cient to produce what he regarded as a state of idiocy. Meynert holds, that the conclusions of experimental physiology strengthen the opinion that intelligence is not limited to defi- * Beevor, "Tuke's Diet.," p. 156. 128 LOCALISATION OF THE MENTAL FACULTIES. iiite cortical areas, but that, being based upon perceptions, including the sensations of innervation, it results from the activiti/ of the entire forehrain. The belief that the exercise of intellectual activity b}^ every part of the cortex depends upon the uniform structxire of all parts of the forebrain, which makes of each part a centre for inductive processes, and supplies to each part nerve-elements capable of perceiving and receiving images, is unsupported by experimentation and pathology. All parts of the forebrain are joined to each other by anatomical association tracts, and the connections of these tracts with other functionally-perfect association tracts in other regions of the cortex, furnished some investigators with the idea of the presence in the brain of an induction apparatus ; and, according to Meynert, the so-called logical sequence in the evolution of association, which yields the factors of intelligence, is effected in various wa3's, and to a varying degree of perfection, in different brains. Let us here, however, briefl}" consider the arguments of those who have attempted to give a rational view of psycho- physiology.* To Hughlings- Jackson t we are indebted for the neural- inference scheme, as given in his well-known '' three level."' " (1) Evolution is a passage from the most to the least organised — that is to say, from the lowest well-organised centres up to the highest least-organised centres. Putting this otherwise, the process is from centres comparatively well organised at birth up to those, the highest centres, which are continually organising through life. {-2) Evolution is a passage from the most simple to the most complex ; again, from the lowest to the highest centres. There is no inconsistency whatever in speaking of centres being at the same time most complex and least organised. Suppose a centre to consist of but two sensory and two motor elements ; if the sensory and motor elements be well joined, so that ' currents flow ' easily from the sensory into the motor elements, * The ratiocinationists (wlio deduce consecjuences or form inferences from the com])arison of premises) follow more or less in the lines of Herbert Spencer, who says, " Every ratiocinative act is the indirect estab- lishment of a definite relation between two things, by the process of estab- lishing a definite relation between two definite relations." — " Psychology," vol. ii. p. 16. t " Evolution and DissoUition." — " Lancet," 1884. HIERARCHY OF NERVOUS CENTRES. 129 then that centre, although a very simple one, is highly organised. On the other hand, we can conceive a centre consisting of four sensory and four motor elements, in which, however, the junctions between the sensory and the motor elements are so imperfect that the nerve-currents meet with much resistance. Here is a centre twice as complex as the one previously spoken of, but of which we may say that it is only half so well organised. (3) Evolution is a passage from the most automatic to the most voluntary. Tlie triple conclusion come to is, that the highest centres, which are the climax of nervous evolution, and which make up the ' organ of mind,' or physical basis of consciousness, are the least organised, the most complex, and the most voluntary. So much for the positive process, by which the nervous system is ' put together ' — evolution." His scheme of the hierarchy of nervous centres is arranged on an anatomico-physiological basis — that is, especially as to degree of indirectness with which each represents the body, or part of it. " (1) The lowest motor centres are the anterior horns of the spinal cord, and also the homologous nuclei for motor cranial nerves higher up. They extend from the lowest spinal anterior horns up to the nuclei for the ocular muscles. They are at once lowest cerebral and lowest cerebellar centres ; hence lesion of them cuts off the parts they repre- sent from the whole central nervous system. "The lowest centres are the most simple and most organised centres : each represents some limited region of the body indirectly, but yet most nearly directly they are representative. The middle motor centres are the convolutions making up Ferrier's motor region and the ganglia of the corpus striatum. These are more complex and less organised, and represent wider regions of the body doubly indirectly; they are representative. The highest motor centres are convolutions in front of the so-called motor region. I say so-called, as I believe, and have urged for many years, that the whole anterior part of the brain is motor, or chiefly motor.* The highest motor centres are the most complex and least organised centres : and represent widest regions (movements of all parts of the body), triply indirectly; they are re-re-representative. That the middle motor centres represent over again what all the lowest motor centres have represented will be disputed by few. I go further, and say that the highest motor centres (frontal lobes) represent over again, in more complex combinations, what the middle motor centres represent. In recapitulation there is increasing complexity, or greater intricacy of representation, so that ultimately the highest motor centres represent, or, in other word?, co-ordinate, movements of all parts of the body in the most special and complex combinations." In regard to the scheme of the sensory centres his conclusions are^ * "Brit. Med. Journ.," March 6, 1869. 9 130 LOCALISATION OF THE MENTAL FACULTIES. (1) That the highest (chiefly) sensory centres, parts behind Ferrier's sensory region, and also the highest (chiefly) motor centres, parts in front of the so-called motor region, make up the physical basis of con- sciousness : and (2) that just as consciousness represents, or is, the whole person psychical, so its anatomical basis (highest centres) repre- sents the whole person physical, represents impressions and movements of all parts of his body ; in old-fashioned language, the highest centres are potentially the whole organism. States of consciousness attend survivals of the fittest states of centres representing the whole organism Meynert has endeavoured to prove a logical sequence in the evolution of association. He follows most authors in regarding the intensity of established associations, as dependent upon their conscious and frequent re-excitation. An accidental suc- cession of impressions is seldom repeated, and relations thus established vanish quickl}^ from the brain. As soon, however, as the '"subjective bond of causality " represents an actual union of things, the re-occurrence of external stimuli will estab- lish a permanent association within the brain. The relation of one mind to another, and the effects of the transmission of approved impressions, is of great interest. Individual intelligence may grow from copying the psychical associations in the minds of others, but any real development of intelligence is only to be gained by the individual's own association of ideas. According to Meynert, projection and association are the two forebrain principles of concei'ted action, and such action constitutes an induction. In this way he seeks to demonstrate, that the widespread activity of the fore- brain serves not only as the recipient, but also as the creator of sensations. Wimdt* called an indiiction the fundamental logical func- tion; but ^leynertf first tried to demonstrate the association and induction mechanism of the forebrain. He believed that l)oth ends of the association fibres were connected centrally with cortical cells. The projection bundles, consisting chiefly (if fibres of the corona-radiata. spreading into the medullary substance of the forel)rain, conduct to the cortex the excita- tions from the external world, and distribute them over its different sensory spheres. All objects which, as soon as per- * " Ueber Menschen und Thierseele." t " Leidesdorf s Manual," 1865. PSYCHOLOGICAL IXFEREXCE SCHEME. 181 ceived. engage tA\'0 different sensory spheres, may appear to prove the existence of an induction mechanism, present every- where in the brain, and anatomically dependent upon the asso- ciation and projection-sj^stems ; but, as we shall see later, the physical compounding of sensations is an unwarrantable assump- tion. Psj'chologically, the mind may receive an impression and then refer to the attributes of that impression, thus draw- ing upon the resources of different sensory spheres ; it does not dra^\' from t^\•o sources at once. Waller* has endeavoured to demonstrate the essential similarity of neural processes concomitant A\'ith the whole range of subjective phenomena from the simplest sensation to the most complex judgment ; but. as his starting point is with the iTltimate fact " sensation,"' we do not in reality gain any further insight from his conception of the physiological mechanism of ratio cinaiion. In analysing the factors of the simplest sensation, as well as of the most complicated judgment, he adopts the logical expressions, major premise, minor premise, and coibchmcju.] In this scheme it is essential to avoid confusion, by distin-- guishing between subjective sensation and activity within the objective substratum of sensitivity. Viewing the subject from the centripetal aspect of neural processes, he appropriates to the three-level scheme the three terms, impjression, sensation, per- ception, using •• impression " as the lowest level term, and taking " impression '' to denote an effect that does not reach consciousness ; '• sensation '"' to denote a felt impression : " pei' ception " to denote a sensation in its felt consequence. The scheme is based on the type of the psychological process of inference, and is as follows : — The simplest present sensation a- is not the concomitant of any isolate present state of organ S, but the resultant of a comparison based S upon state now and state before now — i.e., of a ratio ^j- The organic state now is the sum of many previous alterations of state ; many sensations o- the concomitants of many previous ratios a -, may be conceived as summed up in the state of sensibility 2. * " Brain," 1892, p. 35.^. t Waller does not imply tliat the syllogistic terms of logicians corresi)Oud to any physiological factors in a neural i)rocess. The mental and physiologi- cal states are symbolised by Greek and Roman letters respectively. 132 LOCALISATION OF THE MENTAL FACULTIES. This state of sensibility 2 has as its organic basis a material state, which (liaving regard to the total 2 by many elementary a, each con- S S comitant with a ratio ,) is properly represented as the ideal symbol - . Thus 2 the specific sensibility, the subjective resultant of past experience, is the concomitant of ' ,j, the imaginary organic sum of the antecedent series of organic ratios ^^. To this resultant state (subjectively 2, ol)jectively '- ) he applies the term " personal ratio," meaning to connote in this expression, that the personal state noAv is composed of compared objective phenomena and not of absolute objective phenomena. This personal ratio he takes to be the subjective attribute of the organic major premise, each new sensiflcatory change of state he regards as a minor premise, and considers that a co7icIusion is formed by the com- pounding of these two premises : this compounding or neural inference may, he thinks, properly lie represented symbolically in the form of a multiplication, in which the product represents the conclusion, and at the same time the new major premise in relation to subsequent minor premises. "^ X — = - !t or subjectively a-. But here it is necessary to justify the transition from the use of the word " ratio " to that of the word " premise," and the use of a fractional symbol for both words. The terms of any premise or proposition are the subject and the predicate (joined by the copula) : in a major premise the subject enumerates and the predicate denominates. The major premise *' all men are mortal" maybe written -,,— , , in which we enumerate •^ all mortals " all men " as forming part of " all beings denominated mortals." The minor premise " Socrates is a man " may be written similarly , by which we enumerate Socrates as belonging to the denomi- men nation men just enumerated in the subject of the major premise. And the syllogism may be written : — men Socrates Socrates mortals men mortals major minor conclusion. It would be absurd to say that this or any other mode of symbolisa- tion " explains " judgment, attention, sensation; but it is not too much to say that it clearly exhibits the possible factors of neural inference ; each act of observation, each determination of conduct, is the resultant of two factors : (1) the major premise or central state, more or less attended to ; {2) a particular minor premise or group of sensiflcatory VALUE OF THE RATIOCINATIVE METHOD. 133 stimuli, a]so more or less attended to (within the remaining sensifica- tory field, less or more attended to). Value of the Ratiocinative Method. — The logical mode of symbolising neural processes may serve a purpose ; but, inasmuch as the particular premises — major and minor — are manifestly mental, and only (at least so far as we can imagine them to be) correlates of Mltimate physiological factors, the whole scheme resolves itself into a disquisition upon the ordinary rules of the syllogism, with, in addition, the concep- tion that the physical organism in some way or other subserves the phenomenon of sensation. We shall have occasion to dis- cuss at some leng-th the various theories given to explain the correlation, or, as materialists would say, the "evolution" of a major or minor premise as a sensation in consciousness, and we shall see that the objects of consciousness, as viewed objectively by the subject, are the data, or premises, upon which our conclusions are formed. Here we anticipate by assuming, that the various presentations and representations in consciousness are correlative states to phj^siological activities. Every presentation and representation is an objective content of consciousness, and each content in itself forms a major or minor premise. For an explanation of the formation of that major or minor premise, we must have recourse to metaphysics or philosophy. On the psychical side we have the contents of consciousness, which furnish us with data from which we infer our conclusions. On the physiological side we have various activities "\\'hich resolve themselves into reflex acts, the resiilts of transmitted excitations. It must suffice for the present to recognise that the sum total of the complex phj'siological activities becomes manifested as an objective content of con- sciousness, and that the etjo does not view the activities them- selves; it merely views their mental correlates as objective states. The study of the nervous mechanism has disclosed to us that just as oiir bodies are associated with the activities of the cosmical system, so our organic nervous structures are asso- ciated with the objective phenomena of consciousness. Further, the details of physiology and anatomy ^\■ould appear to point to the fact that some \iltimate and intra-bodily activity is essential to, and possibly conditions every diversification of, the sensory 134 LOCALISATION OF THE MENTAL FACULTIES. and other kinds of experience. Bej^ond this we cannot go. The mere experience of sensory consciousness in itself affords ns no scope for ratiocination. In other words, we believe that our cerebro-spinal system is capable of receiving and of pro- pagating specific agitations, and also of exerting, in some way or other, a determinate modification of activity in its substance ; but A\'e do not in the least degree understand the modus ojjerandi ^'hereby we experience the current vicissitudes of consciousness. Experimental Researches. — We may now return to the consideration of the imcfrontid lohes which have been regarded as especially the seat of intellectual operations. At the International Congress of Experimental Psychology, held in London in 1892. Schiifer challenged the I'esults of the earlier experiments made upon monkeys by Ferrier. In conjunction with Horsley. Schafer found, after bilateral removal of the prse- frontal lubes, that at first the animals appeared apathetic, but that this condition passed off after two or three days. He also regarded the experiments of Hitzig and Goltz upon dogs as doubtful, inasuTuch as antiseptics were not used, and from the small size of the prasfrontal lobes in these animals and their juxtaposition to the psycho-motor or kiuiissthetic area, the symptoms might possiblj^ have been due to an extension of the injury to that region. In order to avoid the shock, consequent upon a bilateral removal of an extensive part of the hemispheres, M'hich is apt to be temporarily followed by a condition of a])athy and apparent idiocy, whether the operations be in the frontal or other regions, tSchafer adopted a modification of the mode of operating, wliereby he did not actiially remove the portions of the brain but severed their connections with the rest of the mantle and the 1)rain-stem. In several instances in which he thus severed the pricfrontal lobes in monkeys there were no appreciable symptoms. From these experiments he could not support the view that tlie ])r;efV()ntal lobes were especiall}'' the seat of intelligent action. Henschen has given an account of a young man A\'ho shot himself. The ball entered the riglit temple ; after perforating the right frontal lobe, it passed back again to the frontal l)one PATHOLOGICAL EVIDENCES. 135 through the left frontal lobe. The man was able to get up and open the door for the police. He also walked downstairs and to the hospital. The Avhole da}^ he seemed to be conscious. and he also spoke a little. At the post-mortem examination a large part of the nerve-fibres from the frontal cortex A^^as severed, and haemorrhage had taken place in the course of the bullet wound. An even more interesting case was admitted to Bethlem Hospital three years ago. A man who had suffered from melancholia, with suicidal tendency, shot himself through the roof of the mouth. The ball passed through the frontal region of the brain and emerged at the top of the frontal bone. After the shock of the injurjr had subsided, the mental condition continued precisely as before, and there was no obvious impairment of consciousness. Nor did the patient at any time manifest any confusion of ideas or subjective change within himself. Ultimately he recovered completely, and still possesses the right use of all his mental faculties. These cases would appear in accordance with the conclusion drawn by Schafer, to demonstrate that the frontal lobe is not necessary for the higher psychical life. Gowers* says, " It is presumed that mental processes are subserved by those parts of the cortex that have no known motor or sensory function, and especially by the prefrontal lobes. Many cases are on record in which considerable mental change was produced by exten- sive disease of this part, especially great when the disease was bilateral. Small lesions, however, may cause no symptoms, perhaps because there is considerable capacity for functional compensation. It A^-ould probabh^, however, be wrong to regard mental processes, as exclusively related to the parts which are not known to have other functions, since the motor and sensory regions must also subserve mental operations." Pathological Evidences. — From the numerous records of injury and disease, implicating the preefrontal region, we are almost bound to conclude that, inasmuch as such injury or disease is not attended by any definite impairment of sensi- bility or motility, the functions of this region are not essential to the phenomena of sensibility and motility, so far as they are evidenced in consciousness. That is to say, the functions of *■ "Diseases of the Nervous System," p. 25. 136 LOCALISATION OF THE MENTAL FACULTIES. the structures which suhserre consciousness may remain unim- paired, and consciousness may be subserved, even though the structures which we imagine to directly serve consciousness be in great part destroyed. Referring to many of the recorded cases of injury, involving the prtefrontal region of the brain, Ferrier* says, " I might multiply instances all demonstrating the fact, that sudden and extensive lacerations may be made in the prsefrontal region, and large portions of the brain-substance may be lost, without causing impairment either of sensation or of motion ; and, indeed, without very evident disturbance of any kind, bodily or mental, especially if the lesion be uni- lateral." Again, refen-ing to a number of cases of softening and abscess in this region, he says, " In all these cases there was an entire absence of sensory or motor paralysis ; and in many there was nothing recorded or nothing calling for special attention as regards the mental condition. In some of them, however, and in one or two others to be referred to. the psychological condition seems to have attracted notice." As we have before observed, the removal of the pra?frontal lobes in monkej^s, followed by alteration in the animals' character and behaviour, furnishes us with no definite proof that the subjective conditions of consciousness were interfered with ; and it is quite possible that their consciousness was intact although their objective expressions were at variance. Bastianf says, " In regard to alterations in the mental condition, these may be either non-appreciable or slight in cases of injury of, or disease in, this brain region. Any such symptoms hare been very frequently absent Avhere there has been damage to the prsefrontal region of the brain only on one side ; whilst, on the other hand, alterations in the mental condition have been not infrequently noted when these regions have been sinuTlta- neously affected in both hemispheres. It has often been difficult precisely to define the nature of the change which has been brought about ; but a dull apathetic condition seems to have been most frequently noticed, together with irrita- bility, vacillation, a diminished power of attention, and a lowering of the moral nature." * "Localisation of Cerebral Disease," 1878, p. 33. t " Paralyses Cerebral, Bulbar, and Spinal," p. 250. PATHOJ.OGICAL EVIDENCES. 137 The following facts about a patient, who was an inmate of the Hospice de Menage (qnoted by Ferrier), are of interest. The lesion in this case was purely cortical, atrophic, and dependent upon partial obliteration of the arterial suppl)^ It occupied the first, second, and third frontal convolutions, and also the internal aspect of both frontal lobes. The ascending frontal, ascending parietal, and paracentral convolutions were intact. The rest of the brain was normal except in the i-egion of the inferior parietal lobule of the right hemisphere. During life his muscular powers and sensation were unimpaired. He was, however, in a state of complete dementia, marching about restlessly the whole day, picking up what came in his way, mute, and oblivious of all wants of nature, and requiring to be tended like a child. Unfortunately, in this case, only the macroscopic changes were described, and, as pointed out by Bastian, there might have been microscopic changes in other parts of the brain similar to those met with in dementia. This conclusion is Cjuite justifiable, and the mental symptoms may have been those of an ordinary demented patient, who presented, over and above what is usual, a definite gross lesion of the frontal lobes. If we ask ourselves the question. Are there any definite signs by which we can, M'ith any degree of certainty, come to a positive diagnosis that disease exists in either prajfrontal region of the brain ? we are forced to answer in the negative. In cases of external injury, disease in the nasal fossfB, or tumours of the orbit, we may be led to infer that the frontal region of the brain has become involved ; bat lesions originat- ing in the frontal lobes themselves are unattended by any symptoms -which have any localising vahie. Instances in which the brain has been extensively diseased without the phenomena of mind being impaired in any sensible degree are exceedingly common. In such instances there may have been destruction of particiilar parts of the brain, or the cerebral mass may have been diseased or destroyed to a con- siderable extent. Ferrier mentioned the case of a man who died of an affection of the brain, and retained all his faculties entire till the very moment of his death, which was sudden. 138 LOCALISATIOX OF THE MEXTAL FACULTIES. On examining his head, tlie whole of the right hemisphere was found destroyed by snppnration. Diemerbrock records a similar case, in Avhicli half a pound of pus \^'as found in the brain, without an}' obvious mental symptoms during life. Marshall has related the remarkable instance in which a man died with a pound of water in his brain, after ha^'ing been long in a state of dementia, but who, a yery short time before death, became perfectly rational. In the cases of idiocy recorded as haying arrest of deyelopment, or atrophy of the frontal lobes, the condition has usually co-existed with similar defects in other regions of the brain. In general paralysis there is no evidence that the mental symptoms can be referred to lesions in the frontal lobe more than to lesions in other parts of the brain. In fact, none of the pathological changes hitherto described enable us to understand the nature and mode of development of mental disorders. In other words, our knowledge of the functions of the human brain, and of the localisation of cerebral disease, is not yet sufficiently advanced to enable us to deter- mine, with any degree of accuracy, the locality and nature o± disease affecting the cerebral hemispheres, and still less are we enabled to localise the cerebral disease, which has morbid mental symj)toms as its accompaniments. The attempts to follow up the clue suggested by the localisa- tion of the speech-centre in the left hemisphere have resulted in the belief, that the entire cortex is the site of language con- ceptions. Similarly with insanity, we have to resort to the belief that the lesions are diffused over the cortex. In speech- affections the mental disturbance is usually much more marked with diffuse disease than with focal lesions. In insanity gene- rally, speech affections are more commonly due to diffuse lesions of the cortex. AYith our advance in knowledge, and improved methods of examining the brain tissues, we shall probably find that, in the main, mental disturbances are associated with . diffuse lesions. Hitherto, the clinical facts of irritative and destructive lesions of some areas of the brain are in accord- ance with the data of experimental research ; but, as yet, such data are not sufficient to furnish precise regional indications. It must suffice for the present to saj^ that we cannot diagnose PATHOLOGICAL EVIDENCES. 139 lesions of the pra?froiital region with an}- degree of certainty from the symptoms. The mental symptoms which may be observed in connection with snch lesions are such that they cannot be distinguished from the general effects of other cerebral diseases, such as embolism, thrombosis, abscess, or tumour. It is obvious, therefoi'e, that in order to come to some decision upon the question of localisation of mental events, it is essential that (1) the contentions of Ferrier. Charcot, Nothnagel— that there is no necessary connection between cortical lesions of the motor zone and affections of sensibility — should harmonise with those of Exner, Luciani, and others, who believe that sensory and motor centres coincide, and that cortical motor lesions affect common sensibility as well as motion; (2) the relations of the sense of movement to the cortical motor zone should be decided ; (3) the functions of the other parts of the cortex should be more definitely known ; (4) the conditions known as word-blindness, word-deafness, etc., should be more closely investigated. When we have gained an adecjuate knowledge of these physiological data we shall be better able to cope with the cpiestions of mental physiology ; but, in the meantime, we must not assign causes where causes cannot be shown to exist, or deduce extempore doctrines from a very partial view of the influence of cerebral disease upon the phenomena of the mind. And so the examples afforded us b}- cerebral pathology do not warrant those partial deductions which form the basis of an irrational materialism. The mind holds intercourse with the external world through the medium of the nervous mechanism, and any disease of that mechanism may impair or suspend this intercourse. We have already mentioned instances in which the brain has been injured or diseased to an extraordinary extent, Avithout any obvious impairment of the mental func- tions. Asylum A\'orkers almost daily Avitness the revival of mental manifestations which have been obscured for a time. In such instances the mind may revive with all its old vigour almost at the moment of dissolution. From the above considerations it will be readily under- stood that some hallucinations and mental changes cannot be explained by physiological perversion. In subsequent chapters. 140 LOCALISATION OF THE MENTAL FACULTIES. therefore, we shall simply assume that disease of the cerebrum impairs or suspends the intercourse of the substantially un- knowable mind with the external ^^'orld. Some writers maintain, that the prsefrontal lobes are all- important in regard to the manifestation of wdiat is known as " attention," and also that they are intimately concerned with emotional states. These views are unverified, and, as Bastian pointed out, it does not require much reflection to show us that an animal from which the prsefrontal lobes have been removed may be dull and apparently careless of what is passing around it, when the incitements and first conditions essential for an alert observant attitude are wanting. Such an animal may easily seem to have undergone a very distinct mental alteration. Meynert's, and Jackson's view, that the highest centres do pro- bably contain nothing but arrangements for representing im- pressions and movements and other arrangements for coupling the activity ofthese arrangements together, is, on the whole, the most satisfactory. James's somewhat broad and vague concep- tion — that currents pouring in from the sense-organs first excite some arrangements, which in turn excite others, until at last a motor discharge downwards of some sort occurs, and that such streams of innervation are accompanied by consciousness, mainly of things seen if the stream is strongest occipitallj^, of things heard if it is strongest temporally, of things felt, etc., if the stream occupies most intensely the "motor zone" — seems in the right direction, but is not sufficient as yet to solve the mystery of the stability and depth of the mind, as evidenced in its mnemonic and subjective powers of recall. Thus far ^\■e have seen that it is impossible to localise mental events within any definite areas in the brain. We know that the brain is the organ or instrument through which stimuli acting on the end organs of sense ultimately reach the mind. Sensations are states of consciousness ; and we are as far off as ever from the conception of any brain activities which could give rise to them. The question as to whether individual parts of mental opera- tions are associated with definite parts of the cortex has, in the case of aphasia and allied conditions, assumed fairly definite proportions ; but, at the best, we must remember, that the CONSCIOUSNESS IN LOWER CENTRES. 141 clinical manifestations in these cases maj^ furnish ns simply and solely with evidences that the physical paths of conduction, or the organic substrata, which in some ^^'ay or other subserve conscious- ness, are not performing their physical functions satisfactorily. We have, on the one hand, to deal with mental activities of ex- treme complexity, to account for which we can imagine no specific functions in the nervous elements which would serve as a physical counterpart; whilst, on the other hand, we have a chaotic mass of tracts, cells, and other nervous elements, which, when viewed either singly or in combination, do not suggest to our minds anj explanation of the very simplest psychical process. Kirchhoff' believes that all internal processes constitute consciousness, and that there are no individual modes of con- sciousness. The processes of consciousness are dependent on the entire nervous system, not on the cerebral cortex alone. Whilst recognising that mental phenomena are entirely dependent upon the physical organisation of the nervous system, we are at present entitled only to say, that the cerebral cortex appears to have a more direct and more intimate relation with the phenomena of consciousness than is manifested by other regions of the cerebro-spinal system. But of that cerebral cortex, we cannot point to any one part as containing the absolutely essential elements to thought in its subjective aspects. James asks, " Is the consciousness which accompanies the activity of the cortex the only consciousness that man has ? or are his lower centres conscious as well ? " In attempting to reply to this cpiestion he fully recognises the difficulties, biit states, " The lower centres themselves may conceivabl}^ all the while have a split-off conscioiisness of their own, similarly ejective to the cortex consciovisness ; but whether they have it or not can never be known from merely introspective evidence. For practical purposes, nevertheless, and limiting the meaning- of the word consciousness to the personal self of the individual, we can pretty confidently answer the question by saj^ng that the cortex is the sole or) By stud}' of the manifestations of mentality in the progress of manlvind from a condition of barljarism to present civilisation ; (e) By examining the development of the individual mind in the higher races of to-da}'. To enter upon a question so large as that of the theory of our mental life, together with reference to the ultimate grounds of knowledge, would be out of place here. We can onlj" take account of the various mental uianifestations, and endeavour to describe or explain them with a view to the demonstration that they are in some way correlated to nervous processes.* For the present, however, just as the physiologist is able to take up the study of his object matter in its one-sided physical aspect, so we propose briefly to glance at the study of mind in its psychical aspect, not indeed as being independent of a physical basis, but as possessing properties which cannot be classed or explained under physical laws. The subjective methods of study are open to this objection, that, no matter how much we study ourselves, the knowledge of our own individuality will be of little iise unless comloined with the knowledge of the individuality of others. Introspection is also necessarily retrospection, for the mind can only reflect, and cannot view its own states at the act;ial time of their occurrence ; or. as Comte puts it, " the thinking- individual cannot di-\dde himself in t^^'0, of which one reflects, while the other sees it reflect." In order, therefore, to obtain facts of any importance, sources of personal error must be * Although the terms "physical process," "nervous process," etc., are employed throughout, they are not to be regarded as e.xplanatory in themselves, or as indicating a known quantity or quality; they merely imply tlie existence of functional activity within the physical executive mechanism . SUBJECTIVE METHODS OF STUDY. 151 corrected by a comparison of the results of self-observation in a number of individuals.'^ Of late years the terms ^^ suhject-consciousness" and " ohjed- consciousness "' have crept into text-books upon insanity, and thej^ are accepted as being self-explanatory. They serve a purpose, inasmuch as they denote, respectively, introspection, the taking- cognisance of the mind's own states subjectively; and, the mental state which takes account of objects external to the individual. In accepting these terms, however, we must not o\erlook the fact, that our physical organism is just as much objective to consciousness as other external facts; and, further, that all the contents of consciousness are in reality objects viewed subjectively, so that the contents of consciousness itself are objective to the self or eijo. Another objection to the introspective method of study, to A\hich allusion was omitted, is the circumstance that recent psychical states ma}^ furnish us with fairly-accurate data, but that when we attempt to deal with remote events, we are exposed to all the errors incident to memory. This, however, need not form a hopeless barrier to our gaining a fairly- accurate knowledge ; and, as before mentioned, ^^■e can render this kno\^'ledg•e more accurate by a comparison of the results obtained by different individuals in order to eliminate the personal error. The objective method, whereby we study the mind ))y means of its external effects, is indispensable to us, especially when we are dealing with its morbid manifesta- tions in the insane. In pathological mental conditions, the "■■ The mind, apart from its physical correlations, may be said to supply a liasis for many sciences.f {a) Psychology, as a whole, supplies the basis of education, or the practical science which aims at cultivating the mind on the side of knowing, feeling, and willing alike. (/;) In its special branches, psychology supplies a basis to the following practical sciences : — Psi/c/iolo(/i/ of Knowimj. — Logic, or the regulation of reasoning processes, together with the allied arts, rhetoric, or the art of persuasion, and that of forming opinion. PsycJwlof/y of Fpcling. — ^Esthetics, or the regulation of feeling according to certain rules or principles — to wit, the admirable, or beautiful. Psychology of Willing. — Ethics, or the determination of the ends of action and the regulation of conduct by principles of right and wrong, together with the allied arts or sciences of politics and legislation. t Sully, "Outlines of Psychology", p. 15. 152 3nNI>. psychologist has an opportunity of observing the phenomena of mind in varying and unusual combinations, and, as we shall see later, this helps us to confirm the theory of evohition by exliil)it- i)ig the reverse order of mental dissolution. The logical methods of studying psychology are also of manifest importance. If we are to argue correctly, and place this science on its right basis, ^^'e cannot afford to dispense with logic. We must have a science based upon proof and evidence, and not a science of belief. '' Logic," sa^^s Mill, •' is. to use the words of Bacon, the ars artium — the science of science itself. All science consists of data, and conclusions from these data ; of proofs, and what they prove. Now. logic points out -what relations must subsist between data and whatever can l)e con- cluded from them ; between proof and anything which it can prove."' No doubt there are many gifted men in our profession who are able to dispense with the recognised formula' of logical and inductive science. They may possess a natural aptitude or intuitive perception of the principles of logic, and furnish us with recondite principles, or ready generalisations. witht)ut a knowledge of the elements of the s^dlogism. Unfortmiately. however, in the stud}^ of psychology, perhaps more than in that of any other science, having to unravel the mysterious i)heno- mena of mind, and investigate the deviations from its normal state, we are peculiarly exposed to many sources of fallacy unless guided by the principles of the inductive process of reasoning. A knowledge of principles and conclusions can iisually only be reached by a succession of steps, after the result of much labour and long-continued reasoning ; and we cannot hope to arrive jjer )on some entity other than ourselves.'' ••In other words, no possible number of entities (call them as you like, >vliether forces, material particles, or mental elements) can sum tltpuiselres together ; each remains, in the sum, what it always A\as ; and the sum itself exists owXy for a ht/stiuoder who happens to overlook the units, and to apprehend the sum as such ; or else * See Royce, " Mind," vi. p. 376; Lotze, " Microcosmus,'" Bk. ii.. Ch. I., § .5 ; Mivart, " Nature and Thought," p. 98 ; Fechner, " Psychophysik,' Bd. ii., Cap. XLA'. ; Brentano, " Psychologie," p. 209 ; Tyndall, " Fragments of .Science," p. 420; Hughlings-Jackson, " Croonian Lectures," 1884, 164 MIND. it exists in tlie shape of some other effect on an entity external to the snni itself." The contention of the spii'itnalists holds good, says James, against any talk aboiTt self-compounding amongst feelings, against any " blending." or " complication." or " mental chemistry." or " psychic synthesis," which supposes a resultant consciousness to float off" from the constituents jje?* se, in the absence of a supernumerary principle of consciousness which the}- iiiay effect. " The mind-stuff theor}^, in short, is unintelligible." The contentions of Ward* and James agree in their main points, and they rightly take objection to the views of •• mind-stuffists," and associationists, that the "series of states" is the awareness of "itself"; that if the states be posited severally, their collective consciousness is eo ii'so given; and that we need no further explanation or "evidence of the fact." If we try to imagine the ideas of the varioiTS. con- stituents of a haggis positing themselves in owy mind, side by side, so as to form a combination or resiiltant idea of the haggis in its entirety, that resultant idea would really consist of a reference to a haggis previously compounded and presented to us in its entirety, while the ideas of the constituents would remain more or less intact and separate. The super-position of mau}^ photographs upon one another gives us a composite product more or less blurred or in- distinct, and the mind loecomes a^^'are of the proj^erties ot that ])roduct as presented to it; biit the mind cannot look at a series of pictiires, and by placing their mental images side by side form a composite mental representation of them. The mind can only review the component parts of the series, and it can only view an external resultant com- bination. f Thus, it deals with the haggis. The taste of * " Eucyclopirdia 15ritaiinica."' t "I tiiul in my students," says .lames, "an almost invincible tendency to think that we can immediately perceive that feelings do combine. ' Wiiat!' they say, 'is not tlie taste of lemonade com])osed of that of lemon plus t\mi oi sugar?' This is taking the combining of objects for that of feelings. The physical lemonade contains both the lemon and the sugar, but its taste does not contain their tastes, for if there are any two things Avhich are certainly ')iot present in the taste of lemonade, those are the lemon-sour on the one hand and tlie sugar-sweet on the other. These tastes are absent utterly. The entiidy new taste Avhich is present resemfiles, it is true, both those tastes." UXCONSCIOUS CEREBRATIOX, 165 the compound may be recognised in its combination, or the ijourmet may even succeed in the detection of elements which would baffle the majority. Let the uninitiated, however, separately imagine the taste of finely-chopped sheep's heart, liver, etc. etc., suet, and oatmeal ; then let him conjure up a high seasoning of onions and pepper, and then let him sum lip the sensation that would correspond to such a compound after it has been '• boiled i the maw." Even a Scot would confess to failure, and refer to the taste of the compound as formerly presented to him-. Of the views of the associationists we shall have much to say in subsecpient chapters, so that we now proceed to consider a question implied by tlie mind- stuff theory — viz., that states of mind may be unconscious. Unconscious Cerebration. The arguments for and against the theory are as follows* : — A(/ainst. Because three men are just able to lift a ton weight one foot, it does not follow that two men are able to lift it 8 inches. For. 1. Below the point of liminal in- tensity of stimulation there must be a certain degree of cerebration, because only a small addition is necessary to produce an appreci- able sensation. 2. The intelligence displayed in so- called automatic acts. 3. Thinking of A, we presently tind ourselves thinking of C. Now B is the natural logical link between A and C, but we have no conscious- ness of having thought of B. It must have been in our mind " un- consciously," and in that state affected the sequence of our ideas. 4. Solving problems during sleep, somnambulism, awakening at a predetermined hour, unconscious thinking, volition, time registra- tion, etc. Consciousness must have presided over these acts. There may have been conscious- ness,but the memory of it absent. Either memory at fault, or B's brain tract alone was adequate to do the whole coupling of A with C, without arousing B. There may have been conscious- ness, but it is forgotten, as in the hypnotic trance. * James, " Principles of Psychology " ; Carpenter, " Mental Physiology," Chap. XIII.; Laycoek, " Edin. Med. Journ.," July, 1838 ; Baldwin, " Handbook of Psychology," Chap. IV. ; Wundt, " Ueber den Einfluss der Philosophie," Antrittsrede (1876), p. 10 ; Hack Tuke, " Unconscious Cerebration "' — " Dictionary," p. 1336. 16G MIND. For. . The complicated processes per- formed in epileptiform uncon- sciousness (larvated epilepsy). , Our conclusions often arrive ([uite unexpectedly without any attempt to analyse their premises. This pre-supposes a mass of ideas in an unconscious state. . The general fitness of instinctive actions indicates unconscious in- telligence, as the ends are not foreseen. . Rapid judgments of size, distance, shape, and the like, are ready-made conscious percepts derived by un- conscious inference. . We constantly discover new ele- ments in accustomed sensations. These elements must have existed in an unconscious state, otherwise we could not single out the sensa- tions containing them from others nearly allied. Affainst. Kapid oblivescence, as in dreams, occurs. Xo such mass of ideas is suppos- able. The predisposition to bring forth a conscious idea is no evidence that the idea existed unconsciously. Brain processes form the predisposi- tion to call forth the idea, just as external physical processes form the predisposition to call forth the brain processes. The actions may be exj)lained physiologically as occurring along the lines of least resist- ance. Results like those of reasoning may accrue without any actual reasoning process unconsciously taking place. We may have an idea and subse- quently know all sorts of things about it. That we 7iotv become aware of the attributes of an object formerly presented is no proof that the awareness of these attributes must have existed unconsciously. That unconscious cereljration can g"0 on, and does go on, without any obvious mental accompaniment is readilj^ con- ceivable ; but \vlien it refers, not to cerebral activities, biit more particularly to mental modifications, without the consciousness of the subject, we find ourselves in difficulties. Undoubtedly, many of the phenomena described as evidences of unconscious cerebration may be compared to the automatic unconscious movements of the liuibs from halu't, as. for instance, in playing the piano. Griesinger has teruied it psychical reflex action. According to the associationists, the development of a single thought is effected l)y the functional activity of association bundles, which unite in a very complicated wa}' the component elemcuts of a so-called residual iuiage of the cortex. These groups UNCONSCIOUS CEREBRATION. 167 of associated cells, which harbour residual images, are the starting- point for the excitation of more comprehensive associations, con- stituting simple processes of induction. In this way every process of thought originating from residual images would be connected with a large mimber of distinct cerebral elements, and it would have, as its physical counterpart j many separate and \\ell-defined areas of excitation, which areas are united for common action b}^ the process of association. Each area is regarded as a separate and fairh^-well-defined group of ganglion- cells, standing in relation to one another through the compli- cated system of association fibres, and every cortical image or inference depends upon the union of these groups of cells. This view, as ^\•e have already seen, precludes the possibility of localising the excitation in the forebrain, and, according to Meynert, the projection system alone stands under the influence of the centres of excitation. For illustration, let us compare the centres of excitation and the projection system to numerous stations on a complicated branching railway. Some associationists hold that the ideas gain their component parts from the separate stations. They imagine that the physical equivalents of these component parts travel either directly or indirectly from their several localities to the central terminus (consciousness) and emerge, not as separate events, but as one event — i.e., the results of the separate events compounded en route. Consciousness, viewed as the central terminus, is not supposed to witness the arrival of individuals, it only witnesses a conglomerate mass of fused passengers. Such is the line of thought advocated by the mind-stuffists, associationists, and unconscious cerebrationists. They postulate that psychological data self-compound into con- clusions. Let us continue the analogy a little further. The official recorder of arrivals (ticket collector) at the terminus, on entering upon his duties, notes the individual arrivals with more or less interest. With the daily repetition of the numerous arrivals, however, his acts of checking become more and more auto- matic, and the individuality of each passenger less distinct, until finally he comes to view, not the individuality of any passenger, but the sum total or mass of individuals, with, 168 MIND. perhaps, some faint qiialifying attribute, such as '• pushiui^-," etc. In the coiirse of his duties he one day experiences the feeling, that a certain face is familiar to him, but he cannot recall where or when he has seen it before. Or a particularly vigorous push by a passenger may make him become aware of the fact, that that same passenger had done the same thing on a former occasion. We might continue the simile, but we should find that ever}^ contingency would fit in with the possi- bility of the occurrences n-ithm the realms of diffitse conscious- ness, and iritliout tJte direct concentratiou of attention. In other words, the realms of diffuse consciousness are so \vide, that they include most of the phenomena regarded as evidences of un- conscious cerebration. The mere fact, that there is inal)ility to recall former conscious events, is insufficient proof that those former events never existed, or that they existed unconsciously. The theor}^ of unconscious cerebration we, therefore, hold to be superfluous and unproved. In his lectures on metaphysics* Sir William Hamilton states, that the greater the number of objects among A\'hich the attention of the mind is distril)uted the feebler and less distinct will be its cognisance of each — plurihiis intentas, minor est ad shufida sensus. As "we shall have occasion to speak more fully of these things when con- sidering the phenomena of trance, somnambulism, hypno- tism, and epilepsy, we will now sum up in general terms our present position with regard to the evolution of mental states. From the affirmation of a universal law of evolution more information is derived than from the affirmation of particulars ; it logically follows, that more information can be derived from the denial of particulars than from the denial of universals — i.e., there are cases left dotditful. That there are cases left doubtfiil requiring the proof or denial of jDarticulars is manifest in current literature upon mental evolution. By the employment of terms such as '■ unconscious inference," " cortical trace," '• subsidiary image," " nascent consciousness," as terms of propositions, we beg questions, and imply the existence of knowledge which Ave reall}^ have not got ; and in * Vol. i., p. 254. UNCONSCIOUS CEEEBEATIOX. 169 the attempt to define that of which we know nothing Ave enter upon the fallacy of a circuliis in definiendo. Thus, if the student Avill sift the terms emploj^ed in the various propositions put forward by the mind-stuffists and cerebralists he will readily detect the abuse and equivocation, brought about, no doubt, by their attempts to substitute terms, the definitions of which they neither restrict nor explain. 170 CHAPTER YI. Sensation. Sensation — Analysis of Sensations and Sense Pei'cepts — Relation of Sensations to Perception — Molar Motions — Atomic and Molecular Motions — Motions of Ether — The Theory of Electricity — Latent Chemical Energy — Power of Selection possessed by Sense Organs — Characters of Sensation — Intensity or Degree — Liminal In- tensity — Forms of Excitation — Weber's Law — Discriminative Sensibility — Maximum Intensity — Fechner's Psycho-Physical Interpretation of Weber's Law — Wundt's Psychological Interpre- tation — The Physiological Interpretation — Validity of Weber's Law — The Estimation of Magnitudes by Comparison — Measure- ment of Absolute Mental Magnitudes Impossible — Quality of Sensations — fleneric and Specific Quality — Duration — Local Characters of Sensations — Taste — Smell — Touch — Specific Func- tions of Tactile Corpuscles or End Bulbs — Pressure Spots — Temperature Sense — Common Sensation — Peripheral Reference of Sensations — Muscular Sense — Hearing — Sight — Pressure Phos- phenes — Quality of Sensations of Sight — Simple and Mixed Colours — Colour - Blindness — Young — Ilelmholtz — Ilering — Wundt — Von Kries — Franklin. In the analysis of sensation and sense-percepts it is necessary (1) to distinguish simple sensations from those derivative and more complex psychic manifestations, to ^\'hich our ediicated consciousness becomes so familiar, that it loses sight of their origin and integration ; (2) to demonstrate the quantitative and qualitative variations of sensations and their relations to the \arious stimuli ; (3) to investigate the psychical metliods whereby our perceptions of time-form and space-form are arrived at ; (4) to estimate the part plav'ed by the various senses, and to see how far the higher mental activities are involved in the processes of perception. The term " sensation " is used to express the most elementary form of conscious experience. It is a mental state resulting ANALYSIS OF SENSATIONS. 171 from the stimulation of the peripheral extremity of a sensory nerve, through which the excitation reaches the sensorium. The senses provide our minds with supply. They fill up oxir con- sciousness with data from which ^\•e gain our ideas. All sensations appear to have some physical occasion. They do not necessarily involve the action of an external stimulus. When a sensory '• incarr3ang" nerve is divided there is no sensation arising from external stimuli, but subjective sensa- tions may still arise through the activity of a central process, the nature of which is unknown to us. In mental diseases such modes of activity Avithin the sensorium are remarkably frecpient. Coupland* regards the term sensation as connoting a sub- jective condition which has no mental but only a physical occa- sion. He claims that a truly original mental phenomenon passes the limits of imagination, because it passes the boundaries of our knowledge. The phenomenon of sensibility may pertain to the organism, but the phenomenon of sensation pertains to the mind. All sensations are modes of behaviour of the mind. Sensations only exist in so far as they form contents of con- sciousness. They are not copies of outside molecular activities ; the}' are modes of conscious activity of the mind. If we take an ordinar}^ psychical activity, and seek to appose it to its material basis, we have to consider (1) the external stimulus, which is physical ; (2) the excitation and transmission of the stimulus ; and (3) the psychical process itself. All our knowledge is obtained from objects presented in con- sciousness, and we cannot propei'ly speak of knowledge where no object is presented. Sensations are the mental objects pre- sented to the subject ; they only exist when presented. This presentation of objects is the first clear act of consciousness. Sensations do not exist except in so far as they are perceived by the subject. Sensations are particularised Avlien perceived, and this perception is the first mental fact. The first psychical element perceived by the mind is sensation ; the first act of A'iewing that sensation is perception. Thus sensation is the first presentation to the consciousness ; perception is the first recognition of that presentation. Sensa- tion is the stimulus within consciousness ; perception is the * " Tuke's Diet, of Psych. Med.," p. 32. 172 SENSATION. appreciation of that stimulus by the mind. What happens within the cerebral hemispheres immediat el}' antecedent to what happens within consciousness is beyond our powers to determine. Ward* thinks a presentation (as presented to a siTliject) might, with advantage, be called an object, or perhaps a psychical object, to dis- tinguish it from ^\'hat are called objects apart from presentation. In the meantime we shall treat of presentations in their literal sense, as presentations to the subject or eijo. Each presentation has a twofold relation : (1) Its relation to the subject ; and (2) its relation to other presentations. Ward states, that the mental facts which we speak of as sensations, perceptions, images, intentions, concepts, notions, etc., have two characteristics in common : (1) Thej' admit of being more or less attended to ; and (2) the}^ can be reproduced and associated together. Thus the term sensihiliti/ would possess a psychical significance, and would denote the mind's capability of having sensations. General sensihiliti/ is that sensibility which represents all the sensitive parts of the organism other than the special sensory organs. Sensations of this character, involving no characteristic nervous structures, are vague and ill-defined. Special sensihiliti/ is the term employed to indicate the mind's sensibility to special sensations, brought about in most cases by external agents through the special senses, and from which we gain a know- ledge of our environment. One simple sensation rarely acts alone. All our senses are open to impressions from \\-ithout. and oiu* minds are constanth' open to impressions from within the body ; so that, just as the external environuient is constantly taking effect upon our physical organism, so the physical organism is constantly taking- effect upon our consciousness. The various kinds of motion which can act upon the peripheral organs of sense are as follows : — (1) Molar motions : the projection or impact of elastic or inelastic bodies. Definite motion is executed in a definite direction by a material body. To this class belong all the stimuli of touch and pressure. (2) Atomic and molecular motions : ^lotions resulting in chemical changes Avitliin and among the molecules. Besides * Jincyclopjedia Britannica, " Psycliology." ATOMIC AND MOLECULAR MOTIONS. 173 the stimuli of taste and smell, many visceral stimuli also pro- bably belong to this class. (3) The '^notions of ether : The vibrations of ether, pervading the space bet\\'een the molecules of matter, according to their velocity, produce the phenomena designated as " light " and " radiant heat," and probably, also, those of " magnetism " and " electricity."* The forms of energy may exist as energies of motion or of position, and the actual constitution of the universe is due, in a great measure, to the alternation of these two energies. The various forms of active energy show themselves as (1) the energy of visible motion, which may be transformed into an ecpiivalent amount of energy of position ; (2) molecular energy, which causes the cohesive attraction, repulsion, and other proper motions of the minute and invisil^le particles of matter ; (3) energy of heat and light, which are transmitted by waves of the assumed imponderable medium called ether ; (4) energy of chemical action, by ^^'hich the small ultimate particles of ponderable matter, called atoms, separate and combine into the various combinations of molecules constituting visible matter, in obedience to cei-tain affinities or inherent attractions and repul- sions ; (5) electrical energy, which includes magnetism as a special instance. We cannot enter into an account of the mutual attractions and repulsions of atoms or molecules ; nor can we discuss the nature of the laws by which these energies manifest themselves. The most subtle and the least understandable of all these indesti'uctible energies is that of electricity. The theory of electricity assumes the existence of two opposite electric fluids, which, in the ordinary or unexcited body, are combined and neutralise one another, but are separated by friction, and flow in opposite directions, accumulating at opposite poles; or, it may be, that one is accumulated at one pole, whilst the other is diffused through some conducting medium and lost sight of. The active electricity, be it positive or negative, thus accumu- lated at one pole, and retained there by the substance in contact with it being a non-conductor, distiirbs by its influence the electrical equilibrium of any body brought near to it, separates * Ziehen, " Physiolog. Psychol." p. 37. 174 SENSATION. its two fluids, and attracts the one opposite to itself. This attraction draws the light body towards it until contact ensues, when the electric fluid of the excited body flows into the smaller one, so that its opposite electricity is expelled, and it is in the same condition as its exciter, and, therefore, liable to be repelled by a similar exciter, or attracted hy the opposite one. which formerly repelled it. The ultimate elements of the material universe are generally taken to be ether, energy, and matter. Of ether, the universal all-pervading medium whose tremors or vibrations, propagated as waves, transport the different forms of eiiergj^, light, heat, and electricity, across space, we know nothing. Neither can we here discuss the dynamical and statical aspects of energy as it manifests itself in gravity, mechanical work, molecular or atomic force, light, heat, electricity, or magnetism. We are unable even to speculate as to the actual nature of energy itself. Some would hold that energy is the one realit}'" of nature, while others would regard the seventy elementary atoms as ultimate facts. In any case, both matter and energy are indestructible, and their present co-existence is not to be explained by evolution. We must, however, at an}^ rate, take some account of the activities of the ultimate elements of which the human organism is built. Tt is impossible to conceive how the human organism can manufacture molecules of living protoplasm like its own out of foreign molecules — i.e., how life manufactures life out of non- living materials. A similar problem awaits us' in the analysis of sensation. The molecular motion external to the body becomes transformed into another form -of energy — the energy of living matter — whilst that, in turn. be(3omes the physical counterpart of consciousness. Dr. Gowers* lias recently drawn attention to the source of energy manifested in the animal body and in the processes of human life, and he believes that everjr form of energy " from a sigh to 9, convulsion," is derived from " latent chemical energy." He discai-ds the old term •' transformation of energy." and sub- stitutes that of the. '"transition of motion." ""We can, I think, perceiv'e all stimuli to be forms of motion. In the case of many physiological stimuli the fact is too obvious to need * ■• Tlu' DvKamics of Life."' NERVE EXER(4Y. 175 consideration, and I believe that, where it is not obvious, the conception will be found to be one from which there is no escape. If tliat which is added is motion, it is probable that the energy which this increases is also motion." It is commonly assumed that nerve-force is of the natiire of molecular or atomic motion ; it remains, however, for us to ask the question. What is the form of that motion ? Dr. Gowers advances the hvpothesis that its source is latent chemical energy, conceived as minute motion, liberated and released by added motion. The nerve-endings receive the different vibra- tions, by which vibrations outward energy presents itself, and which propagate a current or sticcession of vibrations of nerve- energy along the nerve-fibre. The mechanism by which corre- spondence is kept up between the living individual and the surrounding universe may appear to be simple ; but the notion of its simplicity vanishes when we attempt to comprehend the transformation of the vibrations of outward energy into vibra- tions of nerve energy, and more especially do we realise oiir difficulties A\hen Ave attempt to give an account of a specific motion, of which sensation would be the mental counterpart. The two chief groups of stimuli are chemical and mechanical. Hermann * believes that magnetism does not act as a nerve-ii-ritant. Ziehen advocates, that the non- nervous elements of the sense-organ, which first receives the external stimulus, act like a sieve, arresting certain qualities of the irritating motions, and permitting certain other qualities to pass on and irritate the nerve-ends. In this way the orgai\s of sense are regarded as possessing the power of selection. In the new-born brain only can pure sensations be experienced. AVith every subsequent act of mental stimulation the resultant action is made wp in part of antecedent effects. In adults the immense niimber of acquisitions and brain modifications render it almost impossible to realise simple sensations. From an analytic point of view, sensations are thought to differ from perceptions only in the extreme simplicity of the object or content of the former. Sensation's function is that of mere acquaintance with a fact. Perception's function, on the other hand, is knoAvledge about a fact (James). Sensations involve * "Pfliiger Arcliiv.," Bd. 43. 176 SENSATION. nerve-currents coming in from the periphery. In perception it is thought that these nerve-currents arouse associative or reproductive processes in the cortex. Perception would implv the existence of an erjo ; but, inasmucli as the e'/o itself cannot furnish its own material, it also would imply the objective existence of sensations which must be posited as phvsicalh"- occasioned factors. The mind is, therefore, essentially receptive, and depends upon the material which it is able to absorb and hold within itself. Every subjective state is primarily the result of some mental material construed into an objective external reality. Coupland regards the mind as having no creative power. "Along with laws of an object- world there are laws of the subject- world, and we can only realise, imagine, and interpret in accordance with the fixed subjective conditions." Modern psychologists challenge the assumptions that the relation of knowledge logically implies two terms, a knower and a known, and that the knoA\'er must needs be distinct from the known. The opponents of Mr. Ward conceive conscious- ness as analogous to light, which in illuminating other objects illuminates itself also.* The greatest objection urged against the theory that conceives consciousness after the analogy of the eye, which sees other objects but cannot see itself, is found in the difficulty with regard to the knowledge of the subject. Professor James attempts to get rid of the difficult}' by identi- fying the knower as the passing state ; and he finds that this state, just because it knows, cannot, also, be an object of knowledge. Though the subject cannot know itself at the moment when it knows, it is assumed that it can turn and know itself the moment after. The main line of argument adopted by those M'ho uphold the analogy to light is. that, if the subject be not directly experienced or felt, it is impossible to understand how we ever learn of its existence. Were we to say that the theorj^ of life is to be found in the conception that an organism in vitalising other objects vitalises itself also, we should be quite within bounds ; but can we deny the existence of life itself in the abstract merely because its manifestations are the only indications of its existence ? We are unable to form any conception as to the nature of life itself in the * Wundt, "Logik.," ii. 502 ff. CHARACTERS OF SENSATIONS. 177 abstract, but merely because we are unable to do so we do not urge a false theory, that because of that inability there is no such thing as life itself. Similarly with consciousness, the mind in illuminating other objects may illuminate itself also. But, we ask, For whom, or to what, does the illumination occur ? So long as we deal solely and simply with mental manifestations we can appreciate the analogy ; but directly we leave the manifestations and negative the idea of anything beyond, we deny the rights of philosophy to assume that mind itself exists in the abstract, and that we only deal with its manifestations. Later, we shall see that neither the present phenomena nor the representative phenomena of consciousness furnish us Avith a true explanation of conscious experience. For the present we say of mind indestructible, as we said of life indestructible, that merely becaiise the modes of its be- haviour are the only factors with which we are competent to deal, is no argument that there is nothing beyond. Characters of Sensations. — Intensity or degree varies, within certain limits, with the degree or force of a stimulus. The differences in intensity or degree of a sensation instruct our minds as to the natxire and structure of bodies, the forces exerted by them, their distance from us, etc. By the applica- tion of a graduated series of stimuli to a sense-organ, and b}' noting the relation of successive increments to the resulting sensation, it has been possible to establish several laws. When a stimulus reaches a certain intensity* it results in an appreciable sensation. This point of intensity represents the liminal intensity, and the point at which the liminal intensity occurs determines primordially the absolute sensibility of an organ or part of an organ. Whether the method of conduction be mechanical or chemical we are not in a position to say. It is sufficient for us to know, for the present, that the nervous system is in some way or other essential to the conduction of ingoing impulses, and that in some way or other that constitution determines the quality of the sensations. In the attempt to determine the intensity of a sensation many difficulties are met with: (1) We can only estimate the intensity subjectively, and by comparison of sensations ; ]2 178 SENSATION. (2) we can estimate to a certain extent various external physical motions ; but (3) we cannot test the modifications which occur at the peripheral end-organs of sense ; nor (4) can we estimate the intensity or nature of an impulse transmitted or propagated through the sensory nerves to the cerebrum ; and (5) finally, we cannot estimate the nature of the activities which are immediately concerned with the actual production of consciousness. In order, therefore, to determine the exact relationship between an external stimulus and a sensation we must first establish the proportional relations between the external impulse and its phj^siological modifications during the transmission from the end-organs of sense to the sensorium. When we speak of the " magnitude of a stimulus " we speak of a force which is capable of external measurement only, and we are totalh^ ignorant of ^^'hat becomes of that force ^\■ithill the nervous system until it is experienced as a sensation. This is a gap which physiologists will have to fill up before we can bring a brain fact into apposition with a mental fact for the purpose of measurement. From all this the student will readily grasp the fact that, in measuring stimuli, we measure external or phj^sical forces, and not ]3li3^siological forces. Physiological psychology has sought to bring the psychical fact within measurable distance of the physiological fact, but in reality it has only established a numerical or time relationship between the ps3^chic event and an external physical event, there being an unknown physiological process as an intermediary essential to their effective combination. We have already seen that an excitation must reach a certain degree of intensity before it can give rise to a sensation. and that this point determines the lower limit of the absolute sensibility of an organ. This absolute sensibilit}- varies consi- derably — e.r/., that of the sense of smell in the dog is greater than that in man. After the point of liminal intensity is passed there is not always a corresponding increase in the intensity of the sensation when the stimulus is increased. No appreciable change need be effected when there is a ver}- slight increase. The additional amount necessary to produce an appreciable difference in the sensation depends on the absolute intensity of the stimulus. A very slight increment to a small stimulus. WEBER'S LAW. 179 such as would be sufficient to produce an increase of intensity in the case of a feeble sensation, would, in the case of a power- ful one, produce no effect. The law of "Weber or Fechner is : —In order that the interisitii of a sensation maij increase in arithmetical prot/ression, the stimulus must increase in cieometrical progression. The amount of the fraction representing the additional amount of stimulus necessar3r to produce an increase of sensation deter- mines the discriminative sensihility. When we reach a point where sensation is no longer capable of increase — i.e., when no further augmentation is perceived — that point is termed the " maximum of intensity." We shall better comprehend this law with the aid of a simple diagram.* E represents the Fig. 13. first of a series of intensities of excitations. Up to the point 10 the intensity of stimulus is insufficient to cause sensation. At point 14 sensation is first experienced (the liminal intensity). From this point the intensity of the sensation increases with the intensity of the excitation. At a later point, S, although the excitation may continue to be augmented the sensation does not gain in intensit}^ (maximum) but remains constant. Ziehen shows that the sensation does not increase in pro- portion to the stimulus when it has just passed the point of liminal intensity. The crescendo of sensation will present a curve that rises at first swiftly and abruptlj^, then more and more sloA\dy, until it finally vanishes at the point corresponding to the maximum of stimulus, and becomes a straight line parallel to the axis. These three essential features of the sentient hfe — the presence of a minimum and maximum of excitation, and iinally the increase * Ziehen, op. cit., p. 47. 180 SENSATION. of the intensity of the sensation that takes place between the minimum and maximum of stimulation, at first rapidly, and then gradually more slowly — are, according to Ziehen, " exceedingly fitting." " These peculiarities have been developed simply because they are fitting in the struggle for existence. Natural selection is just as efficient in the development of psycho-physiological characteristics as in the development of the purely physiological. The existence of a minimum of excitation protects us from an inundation of small stimuli, that would flood the consciousness by their very superabundance, and prevent the employment of the greater, more important stimuli. The existence of a maximum limit of excitation prevents a super- abundance of too powerful stimuli, and secures the medium stimuli and their concomitant sensations from being overshadowed and over- looked. Both the distracting preponderance of many insignificant stimuli, and the partiality and tyranny of one or a few too potent stimuli, are avoided by this restriction of the sentient life to a range lying between a maximum and minimum of stimulation." The first abrupt ascent in the curve of sensation is also regarded as an indication that the sensation is generally fitting. In consequence of this peculiarity, the same author observes — (1) we are very sensitive to those small stimuli that are just sufficient to produce sensation, in fact, we are very liable to overestimate them ; (2) we estimate tlie medium stimuli very accurately, since here the curve approaches a straight line : and (3) we begin to lose the ability to distinguish the difference in the intensity of only those stimuli that approach the maximum limit. Fecliner tried to give a pst/cho-physical interpretation of the ]a^^' of Weber. Many others have tried to give a phiisiological' interpretation, but the modifications which the excitation must undergo in its propagation render an exact knowledge' im- possible. Wundt gives a third interpretation, the psyclioloriical. He believes that every mental condition is measured in relation to some other by " apperception " — i.e., we become aware of a definite diffei'ence only when the increase of one sensation has reached a certain constant fractional part of another sensation that either preceded or accompanied it. This " apperception " faculty has met with severe criticism and is negatived by most observers. We have seen that Weber's law only holds good in so far as stimuli of medium strength are concerned. As we approach the points of liminal or maximum intensity considerable devia- tions from it occur. It is now more commonl}^ held, that the sensation increases much more slowl}^ than the stimulus, and WEBER'S LAW. 181 that an increase of stimulus sufficient to impart a barely pei- ceptible increment of sensation generally stands in an approxi- mately constant relation to the original magnitude of the stimulus. * The relation between the sensation and the stimulus is of importance, inasmuch as it allows us to apply something of exact measurement to mental magnitudes. The phj^siological interpretation involved in the law of Weber will, however, remain as a useful criterion, because the relation of external to internal stimulus, such as that expressed by the la\\', is as yet only a matter of hypothesis based on the principle of psycho-physical parallelism, and can b}' no means be proven, f The estimate of magnitude is, therefore, made b}' comparison ; but, it must be remembered that, our sensations only furnish us with measures of relative magnitudes — i.e., we are unable to measure absolute mental magnitudes. This statement holds good in every case ; we can only measure relatively by the comparison of magnitudes. VVundt regards the law of the logarithmic relation of sensation to stimulus as a mathe- matical expression for a psychological process of universal validity. This application of the relativity of sensations to the law of Weber has led Wundt to conclude that, in order that a more intensive sensation-magnitude may increase b}' as much as a lesser sensation, the sensation-increase must be corre- spondingly greater ; and two sensation-increases which lie at different parts of the sensation-scale A^-ill be equal I}'' noticeable when they stand in ecjual relations to the stimulation-intensities to which they are added. ij: The student A\'ill now comprehend that, whether a mathe- matical formula can be successfully applied or not, we cannot eliminate from our calculations the relation of one sensation to other sensations. Psychologically, there is no series of abso- lutely independent sensations, but every sensation is determined by its relation to the one experienced immediately before it or * The law of Weber only holds good when attention is given to one sensation of a similar series, to the exclusion of all other sensations. t Wundt, " Hiunan and Animal Psychology," p. 61. X It is assumed that the " attention " remains a constant ([uantity. The magnitude of a sensation also depends upon the amount of attention bestowed upon it. 182 SENSATION. at the same time.* The laiv of relativity is that, from the moment of its first cominp' into beine;, the existence and properties of a sensation are determined by its relation to other sensations.! Quality of Sensations. — When we speak of the ''(jeneric" quality of a sensation, we nse the term in its broad sense to indicate a wide difference of origin (in an orchestra a com- bination of wood-winds, brass, or strings would indicate a generic quality) ; when we wish to signify special qualities or finer differences {e.g., modulations of tone in orchestra), we use the term specific Cjuality. In the study of the quality of sensa- tions we have to ask ourselves, (1) where does the specific excitation give rise to sensation, and what is the nature of the internal physiological stimulus '? We have already said that we are quite unable to answer this question. (2) What kinds of sensations result from the various excitations ? The theory of qualitative selection of stimuli by the end- organs of sense has received favour at the hands of most observers. The various sensory nerves are assumed to possess a specific energy that responds only to specific modes of stimu- lation — e.g., the optic nerves are only sensitive to chemical stimuli produced by the vibration of ether, and the auditory nerves only to acoustic stimuli. We are not in a position to support or to negative this theorj^ We know that mechanical stimulation of the retina in the dark will produce sparks of light, but no amount of difference in the form of stimulation will pro- diice anything else than the sensation of light. Ziehen believes that the adaptation of nervous elements to inadecjuate stimuli is accomplished chiefly in the nervous centre. He also believes that to deny the validity of the theory, as thus understood, would be to contradict all the fundamental principles of evolu- tion, which assert that every function determines the character of its organ, or, in a certain sense, trains its organ for its own use. He therefore rejects W^undt's assumption that, all paths * Hciffding, " Outlines of rsychology," p. 112. t See Wundt, " Animal Psychology '" ; and for its several applications, " Psychology'," Ency. Brit. ; Weber, "Tastsinn und Gemeingefiihl"; Wagners " Physiol. Handwurterbuch," iii. 2, p. 544; Fechner '• Elemente der Psycho- pliysik," i., p. 174 ; .Sclineider, " Vierteljahrsschr. fiir Wissensch. Pliilos., ii., p. 411. QUALITY OF SENSATIONS. 183 and centres are functionally indifferent, and that the processes generated in the central cells are only different because the stimuli are different, and because the irritation is transmitted to the nerve-paths in all its native individuality. That the constitution of the nervous sj^stem is an essential factor in determining the cjuality of sensation we can readily believe ; but we do not in the least know where or how that qualitj" is determined. The duration of all sensations bears some relation to the process of nervous stimulation. The correspondence is not always exact. There may be a lingering effect which is termed " after-sensatio'/i." In sensations of sight we witness such effects as occasional phenomena kno^A'n as positive after-images. In addition to the intensity, quality, and duration of sensations we must take account of the tone of feeling that accompanies every sensation. This, however, will occupy our attention later. A review of the facts in connection with the measurement of sensations leads us to conclude, that (1) statements in proof of the principle of Weber's law are only approximately correct ; (2) from the fact that numerous other factors almost constantly mix^ ^^'ith or intervene between the quantitative amounts of stimuli and their sensations, stimuli and sensations are not connected quantitativel}' in such a simple manner that ^^^e can measure one off in terms of the other ; (3) the psycho-phj'sical explanation of Weber's law, as given by IVchner, is so obscure and speculative that it scarcely merits attention ; (4) the psychological explanation alone can account for the facts within consciousness ; (5) the various laws about the quantitative and qualitative relations between stimuli and sensations must of necessity be Avith reference to external physical and internal psychical facts, the intermediary physiological problem being as yet unsolved. Local Characters of Sensation. — We may arrange the senses in the following ascending order according to their degree of refinement, viz., taste, smell, touch, hearing, sight. The senses of taste and smell are (1) somewhat similar to the organic sensations, inasmuch as there is in them a want of refinement and definiteness. (2) They are of little use as know- 184 SENSATIOX, ledge-giving senses. (3) They do not aid us in localisation in space. (4) Only under special circumstances do they give exact knowledge about objects (e.f/., in wine tasters, etc.). (5) The two senses are easily confused together. (6) Owing to the persistence of these sensations we cannot discriminate two odours and two tastes in rapid succession. (7) Their function is to discriminate what is A\holesome or unwholesome to the organism. (8) Their sensations are caused by chemical stimuli- (9) There is with them a predominance of feeling of pleasure or pain. Sensations of Taste. — The terminations of the gustatory nerves are thought to be only sensitive to chemical stimulation, and it is believed that the sour taste produced by an electric current is caused by the products of electrolysis. The experi- ments of Bois-Reymond and Eosenthal, however, seem to demonstrate that sensations of taste may be due to electrical stimulation. Usually, four classes of tastes are distinguished — sour, sweet, salt, and bitter. To these Wundt* adds alkaline and metallic. The sensations of taste depend upon several other factors, such as smell, touch, common feeling, and muscular sense. The intetisity of taste depends upon (1) the extent of surface excited; (2) the amount of mechanical influence exerted by movements in the mouth ; (3) the temperature also exerts an important influence. Substances too hot or too cold have diminished intensities of tastes. Weber demonstrated that if the tongue is held for half to one minute in very cold water, or in water of about 125° Fahr., the sweet taste of sugar can no longer be perceived. Whether sjiecijic sensations of taste can be excited by mechanical or other means is doubtful. Hitherto the attempt to apply Weber's law to the sense of taste has proved a failure, because so manj- other elements enter into the calculations. Kiesowf found that, besides the whole surface of the tongue, together with its base and the under surface of its tip — the hard and soft palate, the arcus glosso-palatinus, the tonsils, the uvula, the isthmus faucium, the inside of the epiglottis, and the mucous membrane of the cheeks participate in the sense of * " Physiol. Psych ologie," i., p. 382. t " Pliilosopliische Studien,'" Bd. x., Heft. 3, pp. 329 ff. ; Heft. 4, pp. 523 ff. SMELL AND TOUCH. 185 taste. Michelsoii and Langendorff * tested the sensitiveness of the inner epiglottis ; whilst Urbantschitsch tested the mucous membrane of the cheeks in childhood. Iviesow found that all the parts before mentioned are sensitive in childhood; in adults, however, the mucous membrane of the cheeks, the middle of the tongue, and, M'ith a i'ew exceptions, the hard palate lose their sensitiveness. In some cases the under surface of the tip of the tongue on both sides of the frenulum remains receptive also in adults, f Sensations of Smell. — These sensations are supposed to be caused by minute particles contained in odorous gases or vapours. Whether mechanical, electrical, thermic, or other conditions also excite the sensation of smell is doubtful. If the membrane of the regio olfactoria is soaked with fluid, the sense of smell is lost for a time. A scientific classification of the kinds of smells is almost impossible. Just as with the sense of taste, other factors co-operate with the simple qualities and render a differentiation extremely difficult. The validity of Weber's law has not Ijeen tested by the sensations of smell. Sensations of Touch. — The sensations of touch provide us with much more knowledge of space than those of taste or smell, and it is through this sense that we ascertain, to a large extent, the properties of bodies. The sense of touch is finer in the mobile parts of the body than in the fixed. The discriminative ability of the various parts of the body varies considerably ; and, according to W^unclt, J the variations in dis- criminative sensibility at different parts of the same sense- organ do not run parallel to variations in absolute sensibility. Krohn and Bolton§ performed a series of experiaients to delermine * " Ceiitralblatt fiir Physiol.," 1892, p. 204. f The great influence in the region of taste Kiesow ascribes to associa- tion and the effects of contrast. The total results of his investigations upon the conditions of contrast were that — (1) contrasting stimuli must be recog- nised in the sense of taste ; (2) salt contrasts with sweet, salt with sour, sweet with sour ; (3) salt and sweet, and salt and sour, contrast both on simultaneous stimulation of corresponding parts of the tongue, and on successive stimulation of the same taste-surface. The contrasts of sweet and sour could only be observed in the latter case. (4) Bitter forms an exception, but yet perhaps gives rise to contrasts restricted to individuals. X " Physiol. Psychologie," i., cap. 8, § 2, p. M2. § " Joui-. Nerv. and Ment. Disease," March, lb93. 186 SENSATION. the relative sensitiveness of different portions of the skin, to find the nature and direction of the errors of localisation, and to study the influence of attention upon the localisation and interpretation of the simultaneous touch stimulations. It was shown — (1) that the skin over the joints is more sensitive than elsewhere, permitting greater accuracy of localisation ; (2) that touches on the back are more distinctly felt, more clearly remembered, and thei'efore better localised than touches on the front of the body ; (3) that on the left side touches are not so well localised as on the right side ; (4) that localisations are more correct when the touches occur at points removed from the median line — touches on the median line being very poorly located; (5) that exposed surfaces localise better than portions usually covered with clothing ; (6) that piliferous parts are more sensitive ; (7) that errors in localisation follow certain fixed rules ; (8) that the influence of atten- tion is very marked : (9) that the effect of practice is plainly shown ; (10) that two pressure-stimulations are often fused into one single sensation, localised at a point removed from either of those at which the stimulations were received ; (11) that there is a strong tendency to perceive dermal sensations of purely subjective origin ; (12) that bilateral asymmetry of function is plainly evident in dermal sensations. Sensations of touch involve, to a certain extent, the presence of mnsciilar sensations, and this additional factor renders the resuhs of experiment some\\hat nntriist worth)'. That tactual sensations and sensations of muscular innervation do not agree with the law of Weber, near the lower limits of perceptible intensity, is generally admitted. Weber found that a present sensation could be compared with the mnemonic image of one recently experienced, with greater facility than two present sensations could be compared. A stronger sensation of pressure is experienced when the weight is laid on the left than when it is laid on the corresponding part of the right side. The sensations of touch are held to include not only sensations of contact or pressure, but also those of temperature. Cold and heat are sometimes regarded not as direct caloric stimuli, but only as indirect stimuli b}^ warming and cooling the skin beyond its '• phj'siological zero-point."* Weber's law seems to have little or no application to temperature-sensations. The only qualitative law for sensations of temperatiire is, that the skin is most sensitive to changes which lie near its own zero- point. Goldschneiderf investigated the temperature-sense of * Zero-point is supposed to be IS-Jl" C. or 65-66° Falir. t " Arcliiv. f. Anat. u. Physiol., Physiolog. Abth.," 1885. Supplement Band., pp. 60 ff. TOUCH. 187 the body, and found that the sense of cold is little appreciated by the skin of the head, and the sense of heat only in a few places. The sensitiveness of the forehead to cold is intense, but to heat only moderate ; that of the breast to cold moderate along the sternum, and elsewhere very intense, while to heat it is only moderate, except near the nipples ; that of the back, everywhere very intense to cold, and only moderate to heat; «-hile in parts of the hand the intensity of sensitiveness to both cold and heat is alike. In general, the skin in the median line of the body seems much less sensitive to changes in tem- perature than at its sides ; and the number of thermic elements, the thickness of the skin, etc., are determining- factors.* Let us now inquire what histology has taught us as to the specific functions of the so-called tactile corpuscles or end-bulljs. Merkelf has given an account of the different kinds of ter- minal corpuscles. To enter into a description of these varieties, however, is beyond our scope; so we will ask the question briefly, Can the corpuscles of Pacini or Yater, the end-bulbs of Krause, the corpuscles of Wagner or Meissner, or the intricate plexus of non-medullated nerve-fibres of modern his- tology, be proved to possess specific functions for sensations of pressure or temperature ? Ladd answers this cpiestion with the statement, that nothing is kno'\\'n on this point beyond the fact that the skin, within ^^'hich the sensor}' iHbres terminate externall}^ either in free ends or in special tactile corpuscles, is the organ for all the varieties of sensation brought under the most e'eneral meanino- of the word touch. Whether the sensory impression is received by the end- Ijulb, or by the peripheral process between the elements of the integumental and other structures, or not, must be decided by physiologists. Schiifer believes, that the sensory impression is not received by the body of the sensory cell, but by a peripheral process, which, passing either to a special end-organ, such as a tactile corpuscle or end-bulb, or insinuating itself between the elements of the integumental and other structures, receives the * Ladd, "Phys. Psych.," p. 370. t " Ueber die Endigungen der Sensiblen Nerven in der Haut der AVirbel- thiere." Kostok, 1880. 188 SENSATION. impressions whicli caiTse nerve-inipnlses, and transmits those impulses upwards towards the nerve-centres. It is not only the case with those sensations which are received through the surface of the skin or hj the action of the muscles, that sensory- impressions are in the first instance communicated to processes of nerve-cells ; but the same is true for the auditorj^ and for the gustatory organ, the nerve terminations in which do not, as was at one time supposed, emerge from the receptive hair- cells, but really originate from bi-polar or uni-polar cells which are placed somewhere in the course of the sensory nerve, and which resemble the cells found upon the spinal ganglia in sending a peripheral process to penetrate between the (some^\'hat modified) cells of the epithelium, and a central process to penetrate the grey matter of the nerve- centres. In the sensory nerve-trunks a distinction has been made between fibres ^^•hich have to do with painful impressions, and fibres A\'hich have to do with ordinary tactile impressions, the latter, or tactile group, only having to do with the sensations of pressure and temperature. It has also been thought probable that the sensor}^ and tactile nerves have special perceptive centres in the brain. In support of this view we have the following facts : — (1) Sensory and tactile impressions cannot be discharged at the same time from all the parts which are endowed with special sensibility. Tactile sensations, including pressure and temperature, are only discharged from the cover- ings of the skin, the mouth, the entrance to and the floor of the nose, the pharynx, the lower end of the rectum and genito- urinary orifices ; feeble and indistinct sensations of tempera- ture are felt in the oesophagus. Tactile sensations are absent from all internal viscera, as has been proved in man in cases of gastric, intestinal, and urinary fistulas. Pain alone can be dis- charged from these organs. (2) The conduction channels of the tactile and sensory nerves lie in different parts of the spinal cord, which renders probable the assumption that their central and peripheral ends also are different. (3) Very probably the reflex acts discharged by both kinds of nerve-fibres — the tactile and the pathic — are controlled, or even inhibited, by special central nerve-organs. (4) Under pathological conditions, and PRESSURE SPOTS. 189 tinder the action of narcotics, the one sensation may be sup- pressed while the other is retained.* It has been found impossible to classify the various sensations of 'pressure. The pressure sense is supposed to be connected with a specific end-apparatus, arranged in a punctated manner. These points are known as ''pressure spots," and possess varying degrees of sensibility. There are supposed to be separate spots for heat, cold, and touch, and it is thought that each nerve-fibre transmits but one sensation. In the back and thigh these spots are marked by a distinct after-sensation. The pressure-sjDots are, as a rule, denser than the hot and cold spots, and usually have another direction. They vary considerably according to the locality. Kammler and Aubert found the greatest acuteness of sensibility on the forehead, temples, and back of the hand. Eulenburg gave the following order of acuteness : forehead, lips, dorsum of cheeks, temples, etc. The pressure-spots are arranged in chains which radiate from a central point, and run in such directions as to form either circular, longitudinal, or pyramidal figures, f These pressure-spots themselves vary in sensitiveness. The sensation of after-pressure is sometimes very marked, and is liable to cause illusory phenomena. The temperat'ure sense also possesses a similar arrangement of spots, known .as temperature-spots. These spots are insensi- tive to pressure and pain. They are arranged in a linear series, usually slightly curved, and radiate from certain points of the skin, generally the hair-i'oots. The chain of cold-spots does not coincide with the hot-spots. Sometimes spots for other qualities of sensation are mixed with them at scattered points. Tem- perature-spots are ah^'ays more abundant near the hairs, and sometimes only near them. Cold-spots are more abundant than hot. Sensibility for cold is more responsive and more intense than for warmth ; that of the left hand greater than the right. Cominon Sensation. — Sensations of pain, hunger, thirst, fatigue, vertigo, well-being, illness, and the innumerable variety of sensations we experience may occur wherever sensory nerves receive an unusual amount of stimulation. No matter in what part * Landois and Stirling, " Physiology," p. 831. t Ladd, " Phys. Psych.," p. 346. 190 SENSATION. of the nerve's course the stimulation is effected, the pain is referred to its peripheral termination. This is the law of the peripheral reference of sensations. I^ain is seldom strictly uniform or con- tinuous; it is liable to irradiation, or exacerbations in intensity. With increase of nerve-excitabilit}^ there is apt to be increased intensity of pain, and some nerves are more excitable than others. Our knowledge of the ingoing channels of conduction of pain to the brain is deficient. It is generallj^ supposed that toiich, pressure, and temperature impressions travel liy the posterior columns, or perhaps in the lateral sensor}^ tracts, or elsewhere. Pain impressions are thought b}^ Bechterew to pass upwards through the lateral sensorjr tracts. After passing through portions of the posterior columns, they are supposed principall}' to traverse the grey matter of the cord. All that we do know is, that disease or damage of the posterior columns, as well as of the grey matter, often causes delay in the trans- mission of such impressions. Muscular Sense. — The much-vexed question of the relation of the muscular sense to mental states has occupied the attention of nearly every neurologist and psychologist for many vears. The muscular sense is defined as "• the sum of simple mental states or sensations which immediately accom- pany the action of the muscles ;" and, inasmuch as the muscular sensations are due, not to the action of external objects like sense- impressions, but to our own actions, they are regarded as essen- tially active states, and so stand in antithesis to the sensations of the five senses which are passive. They have been described as feelino's of " effort," " exertion," " energv," " innervation," etc. Some say the sensations arise in connection with the process of •' innervation" — i.e., that they are due to the feeling of energy imparted through the efferent nerves. Others say, that the condition is due entirelj^ to sensations arising in the ordinary wav and conveyed through the afferent sensory channels. Others, again, maintain, that probabl}' there is a process both of motor innervation and of sensory stimulation involved, and that the degree of innervation determines the intensity of the sensation of effort. The muscular sense is supposed to stand midway between special and common sensations, and b}' it we obtain a kno^vledge of the condition of our muscles, and to MUSCULAR SENSE. 191 what extent they are contracted ; also the position of the various parts of our bodies and the resistance offered by ex- ternal objects. On the sensations which are conveyed to the sensorium by the muscular sense we form judgments as to the spatial qualities of objects, and in this respect our muscular sense is intimately related to, and often combined with, the exercise of the senses of touch and sight. Muscular sensibility is apparently absent in the heart and all non-striped muscle : whilst many muscles — e.r/., those of respiration — only possess it in a slight degree. The sensibility of the joints, bones, fasciae, serves to inform us about our "position," and this is further aided by sensations of touch. Sensations of motion have been distinguished as active and passive, according to whether we move ourselves or are moved by others. Goldschneider's investigations have made it probable, that the sensation of passive motion depends less upon the successive sensations impai'ted by different positions of the limb at rest, than upon sensations of pressure or friction in the joints directly imparted by the motion itself. Some authors conclude that the sensi- bility of the joints is almost the only essential factor in the production of sensations of motion. The combination of sensations of motion with sensations of touch received from the same object is of special importance. The succession of combined sensations of touch and motion is designated as sensation of active touch. A distinction has also been made between active and passive touch, by the precedence of motor ideas in the former. In the following chapter we shall discuss the " perceptions of space," and later still we shall take account of the view of Bastian that " kinsesthetic impressions, and especially those of which we are least conscious, are the last to be reviewed in the cerebral cortex, anterior to, and as actual last links in, the chain of cerebral processes concerned with and previous to the excitation of the motor-centres themselves." Sensations of Hearing. — The sense of hearing possesses little localising power, and gives us little knowledge of the position of bodies in space, or of their figure and magnitude. Possibly the concha sharpens our hearing very slightly by reflecting vibrations. The external ear in man may be of 192 SENSATION. slight service in localising the direction of sound. Acoustic molecular motions are modified and transmitted by means of the tympanum to the elements of the inner ear. In the laby- rinth the acoustic M'aves become transformed into nerve- commotion by the special end-apparatus of hearing. How the auditory hairs and stones and cells of the vestibule and ampulla3, the rods of Corti, the fibres of the basilar membrane, and the conical hair-cells of Deiters, in the cochlea perform their required functions of analysis of acoustic oscillations, is beyond our scope to inquire. The sensory impressions are supposed to be communicated in the first instance to the processes of the auditory nerve-cells, and not directly to the cells themselves as in the case of the olfactory- cells and the rod-and-cone cells of the retina. In this respect the peripheral reception of their impressions is supposed to resemble those of the tactile and gustator}" organs. From the differences in the mode of reception of impressions in the various sense organs — viz., that the sensations received through the skin and from the auditory and gustatory organs are taken up by the terminal branchings of neurons^ and that the sensa- tions of light and of smell are taken up by the bodies of nerve-cells themselves — one is tempted, gays Schiifer, to generalise from this to the effect that there is some essential difference between the two kinds of receptive organ correlated \\'ith differences of function or of excitation. From the obser- vations of Lenhossek* and Retzius,t upon the sensory cells of the earth-worm, such a generalisation is proved to be invalid. :j: When we enter upon the question of the psycho-physics of the auditory sense we find a great wealth of material at our dis- posal. We are obliged, however, here, as elsewhere, to confine ourselves in the main to the consideration of the relation between the vibratory energy of the air and certain states of consciousness, without attempting to explain the many inter- mediary links. The external vibratory stinivili which determine the subjec- tive mental state, " sound," have been more or less accurately * "Arch, fiir Mikr. Anatomie," 1892, Bd. xxxix. t " Biologische Untersuchungen,"' Neue Folge, 1892, Bd. iii. + See Sciiafer, " Brain," 1893, p. 162. HEAEING. 193 investigated. From a psychical point of view the various sounds have been divided into two classes — viz., tortes, or musical sounds, due to periodic or rhythmical motions of sonorous bodies ; and noises, due to non-periodic motions. Objectively considered, tones and noises invariably accompany one another in some degree ; subjectively considered, the pre- ponderance of the one over the other gives the feeling of pleasure or the reverse. Since all sounds are for us the subjective result of various combinations of tones, both musical sounds and noises may be reduced to a general form of vibration termed in physics a " sinusoid." Sounds of a musical character — that is, sounds which present an appreciable consistency in their rapidity of vibra- tion — depend for their pitch upon the number of vibrations, and for their intensity upon the amplitude of those vibrations. When the rate of vibration is doubled, the octave of the fundamental note is produced. Sounds whose relativity of vibration can be expressed by the simple numerical ratios are perceived, when blended, to be harmonious. Other combina- tions are more or less discordant. The quality of a musical sound, the timhre of a musical instrument, depend upon the number of over-tones or partial tones involved. Thus, there are more partial tones in a violin tone than in the corre- sponding flute tone, etc. Musical sounds may var}^ in loudness, pitch, and quality. These three conditions determine the sound. The pitch of a sound is determined by the number of aerial vibrations exe- cuted in a given time. The lowest vibration-niTmber which can be termed musical is about 16 per second. The musical character continues imperfect until aboiit 40 vibrations per second are reached. The powers of sensory discrimination vaiy considerabh" in different individuals. Some fail in the upper registers, others in the lower. The highest note of the piccolo (4,752 vibrations per second) is practicalh" the superior limit to the scale of pitch in music. If above this degree of acuteness the sound becomes painful. Some individuals possess a fine discrimination for the detection of over-tones ; others acquire the power by training. Habit or experience does much, but not all. A good piccolo player would experience greater diffi- 13 194 SENSATION. culty in tuning a "double-bass" than in tuning his own instrument, and vice versa. The ear is capable of analysing complex aerial waves, thus enabling us to perceive the elements of which they are com- pounded. The aerial wave which reaches the ear at any moment is the summation of the individual systems of waves which are in course of propagation in the vicinity at the time. For instance, the sounds produced in an orchestra are ex- tremely varied, but the aerial waves arising from each instru- ment, as a centre, are superposed, and arrive at the ear as a wave of great complexity. The ear, however, differentiates this intricate combination into simpler elements, and we are enabled to distinguish the sound of the violin from that of the clarionet, etc. In addition to adequate stimuli affecting the end organ of sense, various sensations of sound may arise in connection with electric stimulation of the auditory nerve, or disease of the cerebrum. These subjective effects are, however, simple and often indistinct, until, by repetition, and by a mental pre- paredness or expectancy, the attention evolves them into definite tones or noises having a subjective equivalence to sounds determined by external vibrator}^ causes. The psj^- chological aspects of auditory sensations do not differ in the main from those of other sensations. We must assume a power of sensory discrimination within the mind itself. We shall see later that muscular sensations do not entirely account for all the power of the mind in this direction ; nor can we say that the mind is, in some cases, dependent at all upon the addition of visual spatial relations. The psycho-physical aspects of feeling associated with musical soiTuds and noises, as investigated hy Helmholtz,* give a negative reason for the feeling of dissonance — i.e., the feeling of consonance is due to absence of the successive shocks or " beats," which occur less freqiiently, but more decidedly and unpleasantly as the pitch of the notes becomes more nearl}-' the same.f * " Sensations of Tone," p. 255 f. t " Beats " in music are due to tlie alternate coincidence and interferenct' of two systems of sonorous waves. Wlien two sonorous bodies, wliose IIEAlilXG. 195 111 all marked dissonances such beats occur at the rate of from 20 to 40 per second. The most perfect consonance of two tones results from a note and its octave. Here the coin- cidence or interference of the vibrations is very frequent, for whilst the one note performs one vibration, the octave performs two, and thus there are no beats perceptible. On the other hand, a most unpleasant discord is produced by two notes differing by a semitone — in this case there is great infrequency in the coincidence or interference of the vibrations — and the beats become very marked. Helmholtz found that, as long as no more than four to six beats occur in a second, the ear readily distinguishes the alternate reinforcements of the tone. If the beats be more rapid, the tones grate on the ear. or they become cutting. Roughness of tone is the essential character of dissonance. He also found, that even when the fundamental tones have such widely different pitches that they cannot produce audible beats, the iipper partial tones (over-tones) may beat and make the tone rough. Pettingen gives a positive reason — i.e., that the consonance •or pleasantness of harmony is due to tonicity and ijlionicitii of certain intervals and combined notes. Tonicity is the property'' of being recognised as a constituent of a single fundamental tone, which is designated by the name " tonic." Phonicity is that property of a chord or interval which consists in the possession of certain partial tones that are common to all tones. The first of these qualities of harmony seems to ally the pleasure it jdelds to that which follows even the obscure and only half-conscious perception, as it were, of all relations, as such, between our sensations. The law of Weber, as applied to sensations of sound, has periods of vibration slightly differ, emit sound together, at first the conden- sations and rarefactions which they separately produce in the air coincide, causing an increase in the sound. After a short time, however, the conden- sation produced by the one body encounters the rarefaction produced by the other, and there results a mutual interference, Avhich causes a partial destruction of the sound. Coincidence sets in a second time, to be followed by another interference, and so on. Thus, whilst the bodies continue sound- ing, there will be an alternate increase and diminution of the sound, caused by the coalescence and interference of the vibrations respectively; it is these alternations of loudness and faintness tliat get tlie name of " lieats." 196 SENSATION. given rise to much misconception. By this law we can only compare the intensity of a stimulus with the intensity of a sensation, and we must not include qualitative effects amongst the sensations. The sensation of pitch has nothing to do with the intensity of the sensation, nor has the number of vibrations anything to do with the intensity of the acoustic stimulus. Weber's law is held to be comparatively exact for the intensity of acoustic sensations. The intensity of sound depends upon (1) the distance of the individual from the sounding body. The law of inverse squares is, that in free homogeneous air the intensity varies inversely as the square of the distance. Thus, the distance being as, 1, 2 3, 4, j, ^, the intensities are as, 1. ^, I, ^, 4, 9. (2) The density of the air in which the sound is generated, not upon that in which it is heard ; (3) the amplitude of the vibration — i.e., the intensity is in proportion to the square of the amplitude. Thus, the ampli- tude being as 1, 2, 3, 4, ^, ^. the intensities are as 1, 4, 9 16 i J- To the c^uestion as to whether the same acoustic stimulus can act on several nerve-terminations, or M'hether there is qualitative adaptation of the auditory fibres, so that no two fibres can partake of the same kind of excitation, we shall return when we discuss the power of discrimination of spatial relations. Sensations of Sight. — The transverse vibrations of ether, which are supposed to diffuse light through space, impart sensa- tions of light to the eye. By the periodic vibrations of these particles of ether our mental vision is thought to be governed in a somewhat similar manner to the mode in which our mental ear is governed by the vibrations of soiind. This idea has given rise to the theory, that consciousness is analogous to light, which, in illuminating other objects, illuminates itself also.* Of this theory, and of the other, which regards consciousness as the analogue of the eye itself, which sees other objects, but cannot see itself, we shall have more to say later. Let us now see what data we have for the construction of an intelligible account of the phenomena of vision. The cornea, aqueoiis humour, ci-ystalline lens, and vitreous * Cf. Wmidt, '• Logik.," ii. 502 ff. SIGHT. 197 humour, form the four translucent refracting media of the eye ; their function is to transmit and apply the external stimulus to the retina in the form of an image, and in an order correspond- ing to the external object. To trace the course of the raj^s of light through these media, and to give an account of their indices of refraction, and of the geometrical form and position of their limiting surfaces, is beyond the scope of this work. It mu.st suffice for us to recognise that each refracting surface is separate, and that each one of these refractive media plays its part in projecting an inverted diminished image of the objects of the external A\'orld upon the retina. The construction of the inverted image upon the retina is comparatively simple ; but, as the retinal image is inverted, we have to explain how it is that objects appear upright to us. The impulses from any point of the retina are referred by the mind, to the exterior, in the direc- tion through the nodal point. The image appears to be exter- nal, because all points appear to lie in a surface floating in front of the eye (the "field of vision"). The field of vision is the inverted surface of the retina projected external!}^ ; hence the field of vision appears erect again, as the inverted retinal image is again projected externall3^ With the formation of an image upon the retina we have to give an account of a corresponding physiological process which would serve to conduct the external impression to the sensorium. The retina has to solve the unknown photo-chemical process. Some^^dlere within the nervous and other elements of the retina must be found the specific end apparatus which receives the external stimuli and modifies them into physiological processes. Anato- mists and physiologists refer to the layer of rods and cones as the elements which appear to be directly affected by the action of light. A chemical process is regarded, by most observers, as insufficient. A photo-chemical process is, however, considered as furnishing the best hypothesis. In an ordinary act of vision the external vibratory stimuli determine various photo-chemical retinal effects. The nerve- ends in some way become affected, and transmit or set up excitations, which are conducted to the cerebrum. At present there is considerable doubt as to what visual substances are decomposed in the photo-chemical process. 198 SENSATION. The pupneiitum nirirum is supposed to be of importance in the formation of visual sensations, and the so-called visited jmrjyle is thought to lie related in some way to the susceptdjility of the e^^e for different colours. When the ej-e-ball is pressed we get the so-called " pJios- phenes," or " pressure-pictures." The impression is always referred externally, and is always perceived on the side of the field of vision opposite to where the pressure affects the retina — e.g., pressure upon the outer surface of the eyeball causes the flash of light to appear on the inner side. If the retina is not well lighted, the phosphene appears luminous ; if it is well lighted the phosphene appears as a dark speck, within which the visual perception is momentarily abolished. Purkinje pointed out that if a uniform pressure be applied to the eyeball continuously^, from before backwards, after some time there appear sparkling variable figures, somewhat kaleidoscopic in effect. By applying stead}' and continuous pressure, Steinbach and Purkinje observed a network with moving contents of a bluish-silvery colour, which seemed to correspond to the retinal veins. Vierordt and Laiblin observed the branching of the blood-vessels of the choroid as a red net-work upon a black ground. Houdin believes we ma}'- detect the position of the yelloA\' spot by pressure upon the eyeball. Mechanical and electrical stimuli, when applied to any part of the course of the visual tracts, are liable to cause visual phenomena, although the resulting phenomenon has not the same intensit}^ or clearness as when the cause is due to activity of the ethereal vibrations. Qualitt/ of sensations of svjht. — Under this heading we shall liave to consider chiefly the sensations of colour and light. These impressions fall into a series of gradual changes, ^'arying. for the most part, with the changes in rapidity of the vibrators- stimulus. This is not an invariable rule, however, for consider- able variations may occur in the rate of vibration without an appreciable corresponding effect on the sensation. Hence, the quality of the sensation cannot be said to correspond so exactly with changes in the stimulus as was the case with tone sensations. The degree of colour is dependent upon the pro- portion of white light to the special kind of light. Thus, differ- ences in degrees of saturation of the spectral colours cause SIGHT. 199 considerable variations in the quality of the sensations. Simi- larty, the size of the coloured object and the resulting breadth of the sensation, as well as the intensity of the stimulus, and the time during which it acts, also affect the quality of the sensation. Further, the same stimulus produces different sensa- tions as it falls upon different portions of a normal retina (Ladd). The fineness of discrimination varies with different parts of the retina. From a quantitative point of view the central area, or the area of perfect vision, is more discriminative than the side parts of the retina. The discrimination of degree is much less fine when coloured light is employed.* Light is the chief stimulus which acts upon the retinal elements. Some observers hold, that the retina has a light of its own, which is dvie to the ever-active tonic excitation of its nervous elements by the chemical constituents of the blood. Spectral colours may be arranged in the following order : red, orange, yellow, green, blue, violet. If a beam of white light be transmitted through a prism, the light rays are refracted and dispersed. The dark heat-rays are refracted least ; they are invisible to the retina. The oscillations of the light -ether excite the retina in the following order (of billions per second) : red. 481; orange, 532; yellow, 563; green, 607; blue, 653; indigo, 676 ; violet, 764. The sensations of colour would thus depend upon the number of vibrations of the light ether. The series of colours obtained by the aid of a prism do not, however, include the innumerable shades and varieties of colour A\'ith which our sensations are furnished ; nor can we account for all the variations in the equality of our sensations from the point of view of intensity or rapidity of vibration of the stimulus. Siiuple and mixed colours. — The simple colours are those of the spectrum ; and to the vibrations of which the retina has a corresponding excitation. Mixed, colours are those ^\■hose sensa- tions are produced when the retina is excited by two or more simple colours. The colour u:]bite is a mixtiire of all the colours of the spectrum. When two spectral colours act together and give the colour white, the}' are said to be complementary to each other, or " co')nplemental colours." Any two colours which, * VVundt, "Physiolog. Psychologie,"' i. cap. 8, § 2, p. 335. 200 SENSATION. when mixed, supplement the prevailing tone of the light are termed contrast colours. When a colour is simple and free from mixture with other colours, its colour-tone is said to be ])ure or saturated. The colour-tones of the spectrum pass imperceptibly into one another ; and the fact that the idtra-vQci and ultra-Yio\&t rays do not excite visual sensations is thought to be due to the structure of the retina. Mixed colour-im- pressions vary with the intensity of the various components. Taking into account the number of colour-tones distinguishable by the human eye, together with their variations due to differences in brightness and intensity, Yon Kries estimates that there are about 500,000 to 600,000 colour sensations. At the minimum of intensity of light every colour-tone, except the pure red of spectral saturation, appears colourless when seen alone on a perfectly black ground. The different colours appear and disappear at different degrees of intensity of the stimulus ; green remains visible in the weakest light. Before the maximum of intensit}^ is reached, red and green pass over into yellow ; whilst at the maximum all sensations of colour-tone cease, and even homogeneous rays appear white. Colo'ur-hlindness appears to be due to a defective structure of the retina. The most common form is where the si^ectrum is shortened at the red end. Fick states, that the farther out- ward this imperfect condition of the retina extends, the nearer does the defect approach to total colour-blindness. Kries esti- mates that colour-blind persons are reduced to colours which are either red and blue-green, or greenish-j^ellow and blue- violet. In total colour-blindness only shades of grey from white to black ma}' be visible.* Violet co/o«r-blindness is comparatively infrequent. It has been observed after the administration of santonin. Those who have red-l)linduess see only blue and yellow ; red. orange, and green appear like yellow, and violet like blue. Those who are colour-blind to fifreen see all coloiirs as blue and red. * When the image of an object remains active upon the retina and corresponds to the primary image, this image is termed a 2}ositifr affer- ima(/p: a ne(/ative after-imcu/e is due to the exhaustion of the retinal elements, and is made up of the complementary colours of the objects. COLOUR-SENSATION. 201 Theories of Colour-Sensation. — 1. The Young-Helm- holtz* theory assumes the presence of three different kinds of nerve-elements corresponding to the three primaiy colours — red, green, and violet — in the retina. This theory also assumes that, ever}' colour of the spectrum excites all the kinds of fibres, some of them feebly, others strongly. The elements sensitive to red are most strongly excited by light with the longest wave length, the red rays ; those for green by green rays of medium wave length; those for violet by the rays of shortest wave length, violet rays. The rods of the retina are said to be con- cerned only with the capacity to distinguish quantitative sensa- tions of light. This hypothesis, that there are three special kinds of fibre in the optic-nerve, is quite uncertain, and it does not aid us in the least, from a psychological point of view. Ziehen believes, that all terminations of the nerve-fibres in the central parts of the retina must be very sensitive to many, if not to all, colour stimuli. The theory would explain many of the sensations of light and colour, especially those relating to mixed and complementary colours ; but it does not account sufficiently for the facts of contrast and colour-blindness. 2. The Herinr/ theory \ assumes, that there are six funda- mental colour-tones — viz., black and white, green and red, blue and j^ellow. These three pairs of colours are regarded as antagonistic, the one to the other. The changes which give rise to sensations of black, green, and blue, are assumed to be due to the process of " construction " of a so-called visual sub- stance ; those which give rise to white, red, and yellow are due to the " destruction " of such visual substance. 3. The theorif of Wundt.l — (1) In every retinal excitation there is a chromatic and an achromatic process set iip. (2) The achromatic excitation consists in a uniform photo-chemical process, which reaches its maximum at yellow, and falls off towards both ends of the spectrum. (3) The chromatic excita- tion is a polyform photo-chemical process, which changes con- tinuously with the wave-lengths of light. The extreme differences of this length are such as to produce effects that * Helmholtz, " Physiolog. Optik." t " Zur Lehre vom Lichtsinne, Sitzgsber. d. Wiener Acad.," 1872 — 1874. J " Physiolog. PsyGhologie," i. pp. 450 ff. 202 SENSATION. approximate to each other ; while the effects of certain different intervening wave-lengths are related in such a way, that opposed phases of one and the same movement equalise each other perfectly. (4) Every process of excitation of the retina outlasts the stimulation for a certain time, and exhausts the sensibilit}' of the nerve-substance for that particular form of stimulation. The positive after-images are due to the per- sistence of the retinal excitation — the negative to exhaustion. (5) The phenomena of contrast are to be explained b}" the law of relativity. 4. The theory of Von Kries.^ — (1) Three series of components are requisite — one for the bright and dark, but colourless, sensations ; and two colour-tone series, a red green-series, and a yellow blue-series. (2) White is not to be considered as belonging to the three, since it corresponds to all the colour- tones, whenever they reach a minimum of saturation. (3) The processes corresponding to these three series of com- ponents may be located at different places in the nervous apparatus of vision, either more aentrally or more peripherally. (1) The articulation and adjustment of these three processes are assigned to the central organs. 5. The Franliin tJieori/'f is (1) that in its earliest stage of development, vision consisted of nothing but a sensation of grey (the word grey covering the whole series l^lack-grej'- white). (2) This sensation of grey was brought about by the action upon the nerve-ends of a certain chemical substance set free in the retina under the influence of light. (3) In the course of development of the visual sense, the molecule to be chemically decomposed became so differentiated as to be capable of losing only a part of its exciting substance at once ; three chemical constituents of the excitant of the grey sensation can. therefore, now be present separately (under the infliience of three different parts of the spectrum respectivelv), and they severally cause the sensation of red, green, and blue. (1) But when all three of these substances are present at once, they re-com])ine to produce the excitant of the grey sensation, and thus it happens, that the objective mixing of three coloiirs, in * " .\rcluv. f. Anat. u. Physiol., Abtli.,"' 1882, Appendix, pp. 1-178. t " Iiitt'rnational Congress of J'l\])erimental Psychology," London, 1892. COLOUE-SENSATION. 203 proper proportions, gives a sensation of no colour at all, but only grey. Goller * has given a phj^sical theory, and Donders f a chemical one somewhat like that of Franklin. The distribution of the rods and cones corresponds exactly with the distribution of sensitiveness to just perceptible light and colour excitations,!: and this fact is what we might expect, if we assume, with Franklin, that the rods contain the undeveloped molecules which give us the sensation of grey only, while the cones contain the colour molecules, which cause sensations of grey and of colour both. All the theories hitherto advanced are, of necessity, based upon unverifiable hypotheses. The difficulty in all colour- sensation theories is to account for the fact, that any two com- plemental colours lose themselves in a totally different sensation, and that other sensation-pairs, indistinguishable from these objectively, do nothing of the sort. The physiological require- ments would appear to be better met by the theory of Franklin than by that either of Helmholtz or Hering. § The chief advantage of the theory is shared by that of Donders, which also assumes the partial decomposition of the photo-chemical substance. Sandford || raises the objections (1) that the theory does not account for black, especially for black in simultaneous contrast. (2) Granting that the retinal circulation is rapid enough for the use made of it in explaining simultaneous contrasts, how is the reversal of colours, which is found in the after image of the contrasting field, to be accounted for? Franklin, however, accounts for the sensation of black as the effect on the nerve-ends of the resting condition of the photo-chemical substance ; it is, therefore, the antithesis to every colour as well as to white, and it is the constant back- ground against A\hich all colours and white are seen. In reply to the objection to the explanation of simultaneous con- trast, the phenomena is attributed to a purposeful reflex action. * " Du Bois ReymoncVs Archiv.," 1889. t Grafe, " Archiv. fiir Oijhthalmologie," B.S. 30 (1), 1884. t Fick, "Pfliigers Archiv.," Bd. xliv. s. 441, 1888. § Biirdon-Sanderson, " Nature," vol. 48, p. 469. II " Pysch. Eev.," Jan. 1894, p. 99. 204 SENSATION. In concluding this chapter we may say that, before we can hope to establish a psycho-physiological formula which shall embrace the relationship of the physical activities to the actual sensation (1) we must determine more particularly how the different parts of the retina are arranged together spatiall}^ ; (2) we must endeavour to explain how the physical vibrations of ether, the modes of refraction of the eye, and the spectral characters of light, determine physiological nerve excitation ; (3) we must further test the validity of "Weber's law when applied to the intensity of visual sensations ; * (4) we must determine the anatomical relations of the visual path more accurately. We believe that the external geniculate body, the pulvinar, and the corpora cjuadrigemina anterior, all receive fibres from the optic tracts, but it is uncertain whether they all receive visual fibres. The occipital visual path, the exact centre for vision, and the functions of a great part of the occipital cortex and angular gyrus, are not yet well known. * The researches of Fechner, Merkel, Konig, and Broohun demonstrate that in the case of light stimuli of medium intensity the law of Weber is approxi- mately correct. Deviations occur at the " lower deviation," and owing to the retina's own light. 205 CHAPTEE VII. Pebception. Perception — External and Internal Perception — Apperception — Physio- logical Conditions of Perception — Space Form — Nativistic and Empiristic Theories of Perception — Perception of Spatial Order — Theory of Local Signs — Eccentric Proiection of Sensations — Spatial Discrimination — Special Channels of Perception : Per- ceptions of Smell and Taste ; Hearing ; Touch ; Muscular Sensa- tion; Sight (Retinal, Monocular, Binocular). When we refer sensations to objects in space — that is to say, when we localise or externalise them — we attribute some qualitv to a particular object in space as distinct from the mind which perceives it. Perception is this process of localising sensations and referring them to definite objects, and the result of this process is usually called a loercept. This acceptation of the term is, perhaps, more convenient than the one of some psychologists, which includes sensation and perception as part of the same process. This process of perceiving sensations and referring them to the outer world is sometimes called externcd or sense 'perception, to distinguish it from the cognition of the mind's own states which is termed internal perception. Per- ception is more an act of mind than sensation, which is passive. Early writers employed the term in a wide sense ; recent writers restrict the word to that act of the mind by which we discern an external object by way of the senses.* Perception is, therefore, a mental process which involves. the analysis of a number of sense-data. Wundt has divided perception into shnple perception and apperception; the former being the simple apprehension that we are somehow mentally affected, the latter * Sully, " Outlines of Psychology." 206 . PERCEPTION. being the mental state after discerning attention has been given by the observer to the sense data.* Perception is the invariable accompaniment of sensation, inasmnch as every sen- sation is, more or less, referred to some position in space. This perceptual or localising interpretation \nd,j be slight when the sensation is little attended to, but it occurs nevertheless even in the remote regions of diffuse consciousness. Thias, when we analyse the perceptual process we find that a sensation is first discriminated as a sensation ; then it is identified as pertaining to some particular kind of object, and this involves a germ of representation, or the recalling of other sense-impressions gained by past experience. A perception is, therefore, a complex mental act of which sensations form the component factors. Spencer t regards perception as a '' iwesentcdive representative process " because it contains a presentative element — the actual sensation — and also a number of recalled or representative elements. Wundt does not regard the representative element as essential to perception. Several others speak of percepts in their totality as pi'esentation. For our part, the only percept which we can consider as not involving a representative element, is that attending the first sensation of life ; ever}^ subseqnent percept or process of external reference to sensation is the sum total of previous accjuisitions •; and a representative element is more or less consciously combined with the presentative element in every psychical perceptual act. Perception, as defined b}^ Sully, is "a complex mental act or process, in- volving presentative and representative elements." " Percep- tion is that process by which the mind, after discriminating and identifying a sense-impression (simple or complex) siipple- ments it by an accompaniment or escort of revived sensations, the whole aggregate of actual and revived sensations being- solidified or integrated into the form of a percept — that is, an apparently immediate apprehension or cognition of an ol)ject now present in a particular locality or region of space." Physiological Conditions of Perception. — An act of perception involves the co-operation of different motor as well as sensory-centres. The element of attention is attended * '^Tuke's Diet, of Psych. Med.,"' p. 923. t " Principles of Psychology,'" vol. ii., part VIII., ch. II., p. 513. PHYSIOLOGICAL CONDITIONS. 207 by certain activities of the motor elements. The nervous accompaniments are, therefore, much more complex than in the case of simple sensation. Since sensations themselves are the elements of the so-called presentations of sense, we are forced to accept sensations as the data upon which mental products are formed. Thus sensations are the mental factors upon which the development of all psychical states depends. In regard to the ideas of "space."' "time" (and the "moral sense "). it may be well to say, at the outset, that no attempt will be made in this work to determine Avhether such per- ceptions, in their iiltimate essence, can be resolved into mere transcendental faculties and functional processes of mind. To the physiologist, above all other auen, it would appear to be clear that, whatever may be the ultimate foundations of their existence, as associated with other causes and effects of our physical and mental life than those we know, the mode of their appearance with us is distinctly empirical, and depends directly, in regard to each psychic manifestation, upon the quality and combinations of the stimuli both exoneural and esoneural. which give rise to that manifestation. And, therefore, following in the footsteps of those workers who have given their attention to the distinctly practical side of this subject, it will be sufficient, for our purpose, to inquire ho^^^ the appearance of these uiodes seems to become manifest through excitations of the special organs of sense, external and internal, and through the combination of the effects of siich excitations. Presentations of sense differ from simple sensations, in that they exhibit the psychical power of estimating space form. In order to explain on what combinations of physical processes of sense, the different resulting sensations are combined into pre- sentations of sense lender the new characteristic of space-form, the following truths are to be recognised : — '"' 1. A combination of two or more qualitatively different series of sensations is necessary. 2. There must be adaptability of special senses to form a graded series of the characteristic differences in c|uality of sensations (e.f/., spatial series of sight and touch), called the geometrical senses. * Ladd, " Phys. Psych.,"' p. 38.5 208 PERCEPTION. 3. There must be a mental representative in the sensations which stimulation of the different parts of the organ of sense calls forth (the theory of ''local signs"). 4. Various stages in the process of elaborating the presen- tations of sense, from the material of simple sensations, must be recognised. These stages are (a) localisation, or the trans- ference of the composite sensations from mere states of the mind, to processes or conditions associated with more or less definitely fixed points or areas of the body ; and (/?) eccentric jn-ojection, or the giving to these sensations an objective existence as qualities of objects situated within a field of space, and in contact with, or more or less remotely distinct from, the body. The law of eccentric projection is, " Objects are perceived in space as situated in a right line off the ends of the nerve-fibres which they irritate." 5. A constant activity of mind is presupposed, whereby presentations of sense are elaborated (by synthesis) by the mind itself. Theories as to the origin of presentations of sense. — Two theories have been given to account for the genesis of presentations, and these have been termed the ' nativistic,' and ' empiristic' The nativistic theory (Helmholtz) assumes the presence of an intuitive or underived activity of the mind, which enables the mind to appreciate the characters of the pi'esentations of sense by force of its own inherent funda- mental capabilities. It also assumes that a definite point in space is allotted to each of the retinal points from birth, which would account for some of the spatial relations of presenta- tions. The emjnristic or genetic theory objects to the mind's native intuition. It denies the native power of the mind to intuit space, and relies upon kina^sthetic. muscular, and tactual sensations to account for the spatial phenomena. The advo- cates of either of these theories must admit, that sensations are presentations to the mind, and that unless the mind perceives them they are not presentations. The perceptual power of the mind is dependent upon the presentations of sense for its development, but the individual presentations do not mass themselves into a " mind-stiiff" which corresponds to percep- tion : that is to say, the sensations do not present them- ORIGIN OF PRESENTATIONS. 209 selves to themselves, and by their combination evolve perception. No matter how much the empiristic school advocates the laws of development, it must still admit the so-called native power of the mind as that which perceives. Ziehen adopts the genetic standpoint to account for the spatial rela- tions of sight, but he admits that in the course of the phylo- genetic development of the animal series, that capacity to localise visual sensations was first developed, which made the eye a proper organ for the perception of space. He says, " We find the wonderful rapidity with which this arrangement of the sensations is accomplished inconceivable ; at once, without a moment's thoxTght, the image is before us, well arranged and unmarred by the slightest error. To be sure, a process of evolution, extending through almost endless ages, was necessary to produce and train a cortical apparatus that can react with such fitness. The new-born animal or child inherits this apparatus. Each single individual does not need to acquire it again laboriously, but only to learn to use it." This attempt to shift the native power to the ancestry must be the method of procedure of all empiristics. The nervous organism of every child probably does inherit an innate power of co-ordinating certain retinal sensations with sensations of ocular movement, and visual sensations with experiences of active touch ; by a slow process of acquisition, however, the muscular and tactual sensations become more or less absorbed in the visual elements, so that the comprehensive range of vision far exceeds, and becomes in a manner independent of, the muscular and touch elements. This hypothesis of inherited tendenc}^ accords more with the theory of an original intuitive knowledge, than with the opposite theor}^ of a derived space- intuition. Schopenhauer, Spencer, Hartmann, Wundt, Helmholtz, and Buret, have held the opinion, that perception is a sort of reasonhig operation, more or less vmconsciousl}^ and aiito- matically performed, which is equivalent to sajdng that the characters, qualitative and spatial, of external objects are treated, combined, and arranged, by the nervous apparatus, and handed to consciousness in their new form as fully developed percepts. 14 210 PERCEPTIOX. We have already mentioned that the localisation of organic visceral sensations is confused and indistinct. The exoneural reference by the special senses is much more acciirate and defined. The mind passes from the mental phenomenon, the sensation, to the contemplation of the object which it serves to qualify. The theory, that in sensations of hearino-. touch, sight, and pain, we are accustomed to distinguish from among the other elements the elements of rolmninousness, has much in its favour. Professor James holds, that this element of voluminousness is discernible in each and every sensation, though more developed in some than in others, and that it is the original sensation of space, out of which all the exact knowledge about space that we afterwards come to have is woven by processes of discrimination, association, and selection. The jierception of sjintlal order. — To account for the order in which space perceptions are arranged in our minds, two theories have been advocated. 1. By the one, the spatial order would appear to result from the massing together of a multitude of sense-space phenomena in consciousness, and this, through the inter- vention of physiological processes, equivalent to the pro- cesses of the " mind-stuflists." Thus the abstract pheno- menon of spatial order is supposed to be formed by the synthesis of concrete perceptions ; the physiological processes, which correspond to the estimation of figures, magnitudes, and distances, are held to combine in an orderl)-- '\\'ay. giving, as the result of their combination, an abstract apprehension of spatial order. 2. The other theor}^ assumes that, for the orderly arrange- ment of a multitude of sense-spaces in consciousness, something more than their mere separate existence is required. In order that a sensation may be discriminated spatially, it is essential that the various extents of the objects should be perceived as part of the total extent. This would imply, either that the various extents are perceived in a definite order, or that they are perceived by the mind synchronously, and at once. The difficulty, therefore, arises of having to account for the dis- crimination not only of co-existent spatial extents, but also of co-existent sounds and extents of other senses. LOCALISATIOX. 211 Some authors uphold the view that a new element comes into play when the mind estimates or perceives some spatial relation. The relation, when perceived, however, is nothing- more than a sensation which is perceived. That is to say, the relation of" two bodies in space, the line of demarcation betweeiil the two, or the particular forms of transition between two'/ sensations, are as definitely sensational, in their subjecti\'ei aspects, as the sensations of all related bodies themselves. Spatial knowledge, therefore, like every other form of know ledge, as we know it, depends upon sensations. The mind would appear to pass from its comprehensive view of the vaster extents to an analysis of spatial relations in detail. Localisation, or the theory of " local signs." — It is assumed, that every visual and tactual sensation derives its peculiar shade of feeling from the peculiarities of the end- organ of sense stimulated. These local contrasts of sensations have been termed "specific qualia,'^ '-local-colouriw/s," or "local spinsf In referring to a local sign, we refer to a thing having a position in space, and this is determined by its relations to other positions in space. When we refer to two separate points we become a's^'are of an interval, which is unexcited, between the two points. We can localise one point only in its relation to the whole body, and t\\o points in their relation to each other. In both cases, however, we refer the points to some part of a visual image of the bod}^ In an ordinary way we are apt to utilise the fittest part of our sensors- mechanism to discriminate sensory events. We employ the most sensitive parts of our limbs to investigate the nature of a local stimulus, and in a similar way the fovea and yellow spot of the retina are employed when we wish to focus our attention more particularly upon some visual object. The movement bringing the fovea into direct action involves a transition of action from the retinal elements first stimulated to the elements possessing greater discriminative sensibility. In this way ^ve get an " ideal streali, " (James) awakened first at the point of retinal stimulation and extended to the centre of focus. Professor James believes that the result of this incessant trac- ing of radii is, that whenever a local sign is a\\'akened by a sjoot of light falling upon it, it recalls forth^vith, even though the 212 PERCEPTION. e}' eball be unmoved, the local signs of all the other points which lie between the first spots stimulated and the fovea. In this wa}^ no ray of light can fall on any retinal spot ^^'ithout the local sign of that spot revealing to us, by recalling the line of its most habitual associates, its direction and distance from the centre of the field. The fovea is thus regarded as the origin of a system of " polar co-ordinates." in relation to which each and every retinal point has, through an incessantly repeated pro- cess of association, its distance and direction determined. The physical basis of this process of localising b}^ local signs is, therefore, supposed to depend upon the connection between sensory and motor nerves ; and, according to Lotze, the local character of every colour-impression is due to the excitations of the central endings of the motor nerves, and the sign determines the motor tendencies, or associated feelings of Inovement. The theor}- of local signs, as applied to tactual sensations, has received much attention, and it is regarded as comparativeh' certain that local signs facilitate the localisation of sensations of pressure, and that the same stimulus, acting upon different nerve-fibres separateh', also causes a slight]}^ perceptible difference in qualit}^ of the resulting sensation. From these considerations we are noA\- in a position to recognise, that the capability of localisation of sensations of sight and of pressure is due to the difference in the sensations produced when a stimulus acts upon different nerve-ends separatel3^ The localisation is brought about by the aid of association. The mere sensation in itself is insufficient ; it only aids us in localising by means of its local sign, and this again is further aided by its relativity as evidenced through the " ideal-streak." Eccentric Projection of Sensation. — How a sensation can be projected into space is quite inconceivable. We are not warranted in assuming that a sensation becomes manifested psychically in the region of the bodily processes from which it has its starting point. Sensations are the mental equivalents of cerebral processes, and these cerebral processes are the physio- logical effects of physically-determined processes elsewhere. The eccentric projection of sensations is thought to involve a somewhat different class of sensations, and the process of attention is regarded as often determining between the moiifs to ECCENTRIC PROJECTION. 213 localisation and those to eccentric projection. The two mntually opposing views are : (1) The system of miTSCular sensations of movement and the system of visual sensations are thought to combine to develop our perceptions of objective space in its three dimensions ; the sensations of touch being subsequently projected into a space thus originally constituted b}' combined muscular sensations and visual sensations. The eye and hand in motion are, therefore, thought to project their extended objects into a space which they develop themselves ; while the ear and the nose project their perceptions into a space which they are compelled to assume on the authority of the other senses (Ladd). (2) In opposition to this view, we are more inclined to believe, with James, that the objectivity with which each of our sensations originally comes to us is not, iu the first instance, relative to any other sensation. That is to say, our perception of space is primarilij one of vastness ; the' spatial relations themselves are secondarily determined by a process of analysis, and this by the activities of our mu^scular and visual senses. When we speak of hallucinations and the various perversions of the sense of movement, we shall see that we almost constantly regard the seat of stimiTlation as the seat of sensation also. This tendency is the natural out- come of our habitual reference to sensations as exoneural. In our ordinary waking moments ^^'e regard many of our sensa- tions as external realities ; others we regard as merely the mental counterparts or imaginings of physically-occasioned sensations. In reality, of course, the sensation is in both cases the ps5'chical equivalent of cerebral effects, either peri- pherally or centrally determined. In dream states, and in artificially induced hypnosis, however, the hallucinatory in- tensification of the exoneural reference of sensations is often morbidly exaggerated. Similarly, in the insane, passing ideas may accjviire hallucinatory strength, and there is failure to recognise their true objective import. We shall have occasion, however, to return to these considerations, so we now pass to the cjuestion as to how the various actual presentations of sense are elaborated by the mind itself. Spatial discrimination is dependent upon — 1. Certain conditions of the sense-spaces — i.e., each space 214 PERCEPTION. must contain its special local sign ; two spaces which have the same local sign cannot be discriminated from each other. Unless these local sense-spaces are excited by external stimuli, there is little or no local difference of feeling. 2. Partial stimulation must be possible, otherwise no power of differentiation would be afforded to the sensitive surface. In order that a sensation may be aroused, the local differences murERCEPTI0X. 227 the mental interpretation of the false sensory impression to be the abstract result of a fallacy of the senses. We have already discussed the law of the specific energy of nerves, and we have spoken of adequate (or homologous) stimuli. We have also briefly referred to stimuli (heterologoiTs) which act upon the nervous elements of the sensory apparatus along the entire course from the end-organ to the cortex cerebri. These latter stimuli, when of internal somatic origin, give rise to subjective mental phenomena of varj' ing degrees of quality and intensity. In the sane person there is a constant liability to errors of perception. Illusions are common to us all. Our discrimina- tive power is necessarily limited and defective. Thus the study of sensory perversions belongs both to the psychologist and to the mental pathologist. There is no sudden break between the illusions of the sane and those of the insane, and there is often great difficult}- in distinguishing between them. Our judgments are liable to be distorted at any time, and our sensory discriminations ma}- be at variance. Any emotional disturbance, any state of exhaustion, inattention, expectancy, or mental preparedness, may favour the development of some false sensor}- perception. The transition from sane to insane perceptions is often difficult to demonstrate. In the intermediate conditions, half-^^■ay conditions between sanity and insanity, we have man}- examples of sensor}- dis- turbances. Thus in some dream-states, nio-ht-mare. relifiious fanaticism, and many excessive emotional states. M'e have perversions which are suggestive of a neiirosis rather than true nerve health. In hysterical temperaments, especially, do we find illusor}- morbid conditions. In the sane, the illusory percepts may be due to defective knowledge ; or the illusory nature of the percepts may be recognised by the individuals in whom they occur as the results of defective energisation. In the intermediate states there is often failure to recognise the true natui-e of the illusory phenomena at the time of their occurrence, but this knowledge may be gained at some subsequent period. In the insane ihi'Ye is not only a failure to recognise the true nature of the phenomena, l^ut also a belief in their objective 228 SEXSORV PERVERSIONS. realit}^, and, as a consequence, there is a tendency on the part of the individual in whom they occur to act npon the false evidence presented to the mind by way of the senses. Definitions of Illusion. — In order that we may fully comprehend the meaning of an illusion, we must take account of its factors from several points of view To define it as a false sensoiy perception is insufficient. There is a standard of falseness, and one must remember that human experience is fairly consistent. Our perceptions and beliefs fall into a con- sensus. Some metaphysicians hold the idealistic view, that perception itself is an illusion, inasmuch as it involves the fiction of a real thing independent of the mind, j^et somehow present to it in the act of sense-perception. "With this question, however, we have nothing to do. An illusion is further defined as a " mistaken identity" — i.e., a partial displacement of an external fact hj a fiction of the imagination. Another definition is, that an illusion is a false percept which arises in the mind of an individual under circumstances which would not give rise to similar percepts in the case of other people. This is still, however, inadequate. There are special circumstances which are fitted to excite a momentary illusion in all minds — e.(j., optical illusions may be due to refraction of light, reflection, etc.. and these ma};" arise in all minds under precisely similar circumstances. Any definition must be relative. The false percept must be one that can be contradicted by a more accurate percept ; or, as Sully puts it, it is a deviation from the common or collective ex- ])erience. This deviation, as met with in the insane, is a species of perceptual error, which is peculiar to the individual, and, as we shall see later, it involves not only present sense-data but also other psychical factors. The sources of illusions of joerception are : (1) Suitable soil ; a neurotic type, or physical preparedness, due to inherit- ance or disease. (2) PJxpectancy ; a mental preparedness is the .most prominent factor in the causation of so-called "active" illusions, (o) Inattention or incomplete attention to the sense presentation. CUosely allied to this is (4) confusion of sense- impression. In the regions of hascy impression, or of diffuse consciousness, illusions are most apt to occur, and play the ILLUSIONS. 229 greatest pranks. Every cricketer appreciates the difficulty, or confusion of sense-impression, that is apt to arise when there is any movement in the field behind the bowler's arm. In the same way, the presence of a swallow on the cricket field, as viewed by the retinal points outside the field of central focus, is apt to give a confused impression of a ball moving in space. Organic sensations, occurring in the regions of sub-conscious- ness in both sleeping and waking moments or between them, give rise to illusions. (5) In mental states, which are the result of habits of inaccurate discrimination — i.e., in mental states built upon data which have not been analysed — the interpretation of the present sense-impression is apt to follow the law of habit, and the habit of loose inference, or misinterpretation of sense- impressions, may result in the accjuisition of so-called uncon- scious fallacious inferences, and fallacious conclusions from present determining sense-data. Varieties of Illusions of Perception. — These have been arranged according as they arise from without, by suggestion of external or physical factors ; or, as they arise from within, due to the development of preperception, or the element of expectancy. The former have been termed passive illusions, the latter actire. The factors of causation may be grouped in the following order : — * PASSIVE ILLUSIONS. 1. Exoneural, determined by — (a) Exceptional external arrangements. (h) Exceptional relation of stimulus to organ. (c) Illusions of art. (d) The particular forms of objects. (e) The points of similarity of objects. ( /) The reverse illusions of orientation. 2. Esoneural, determined by — (rt) The limits of sensibility : Degree of stimulus. After sensations. Number of stimuli. Specific energy of nerves. Fusion of stimuli. Eccentric projection. * See Sully's " Illusions." 230 SEXSOKY PEin'ERSIONS. (/') Bi/ the variations in sensihilitij : (1) Momentary, or transient, caused by fatigue, malnutrition, or toxic agents. (2) Permanent, caused by variations in excita- bility of sensory organs, hereditarj' or acquired. In conditions of hypera?stliesia, anesthesia, and partestliesia. ACTIVE ILLUSIONS, A\'liicli involve the element of expectancy : — 1. Vohmtary selection of interpretation. 2. Involuntary mental pre-adjustment. (a) Temporarij expectaiion or preparedness : Sith-expedaiion. Vivid expectation. both of which ma}' arise from — Present objective facts. Verbal suggestion. Imagination. {!>) Comparatireh/ permanent disposition, as seen in the evolution of conceit, hypochon- driasis, etc. In the account of all these states, it must be remembered, that every function is rendered more facile b}^ exercise, and that illusions become more real by repetition. Passive Illusions determined by environment — 1. Exceptional exfenud arrannements. — The ordinary physical j)henomeua of the refraction of light and the reflection of sound. A stick half-immersed in water appears to be bent. The optical illusions of magnitude, due to external conditions, are numerous and well known. The atmosphere has to account for various illusions as to distance. Thus, the person unused to the clear atmospliere of Switzerland is unable to realise distances. At times, great difficulty is experienced in deter- EXONEURAL CAUSES. 231 niining whether our train or the one alongside it is moving. When we move forward all objects appear to glide backwards. The faster we go, the nearer do the objects seem, and the nearer they seem, the smaller do the}' look. This fact is explained by the greater rapidity of their apparent translocation (Helmholtz). 2. Exceptional relationship of stimulus to onjan. — Aristotle's experiment, of crossing two fingers of the same hand and rolling a pea l^etween them, is attended by the illusion of there being two peas instead of one. Each of the two points of contact has its local sign ; but, from their inexperience of working in unison under certain particular conditions, there is distortion of the inference. In a similar way the experience of having "sea- legs " on land is to be explained by the absence of the accus- tomed landulations of the structure on ^^■hich we walk, and the ^\'ant of the customary tactual and surface sensation experi- ences. The examples given by Sull}^ afford further illustration. When a man crmiches a biscuit, the sound is intensified owing to the propagation of the stimulus by other channels than the usual one of the ear. If the two hands are bent into a sort of auricle, and placed in front of the ears, the back of the hand being in front, the sense of direction, as well as of distance, is confused. Thus, sounds really travelling from a point in front of the head will appear to come from behind it. Objects appear smaller and at a greater distance when one eye is used than when both are used. Illusions of movement occur owing to our eyes moving without our knowing it. Perception of an object's movement depends upon the sense of movement in our own eyes. James regards the original visual feeling of move- ment as produced by an image passing over the retina. He says, " This sensation is definitely referred neither to the object nor to the eyes. Such definite reference grows up later, and obeys certain simple laws. We believe objects to move (1) whenever we u'et the retinal movement feeling- but think our eyes are still ; and (2) whenever we think that our eyes move, but fail to get the retinal movement feeling. We believe objects to be still, on the contrary, (1) whenever we get the retinal movement feeling, but think our eyes are moving ; and (2) whenever we neither think our eyes are moving, nor get the retinal movement feelino'." 232 SENSORY PERVERSIONS. 3. Illusions of art. — Pictorial art aims at stereoscopic effects, and seeks to give to flat surfaces the illusory effect of depth, relief, and solidity. By means of colour in various qualitative and quantitative degrees, an imitation of natural objects is sought. This imitation suggests to the mind the habitual interpretation of natural sense-impressions, and hence the imitative art is a source of complete illusory effects. The illusion that the eye in a portrait seems to follow the spectator is due to the fact that the surface of the portrait is flat, so that the profile of the object is never seen. 4. Misinterpretaiion of form and local arranhis emotional disturbances of central origin. Ziehen believes that in hallucinations of the insane the process of sensation, which normally always proceeds from the sensory elements to the memory elements, now takes the reverse course from the latter to the former. He says : " It is 262 HALLUCIXATI(3XS. only when the sensory cells are morbidly irritable that they react upon a stimulation from the memory-cells, Avhich, under normal conditions, would have no effect upon them, but which has been pathologically intensified. The sensation-cells are sympatheticall}^ excited, as it A\-ere. It is obvious that but two chief cases are to be distinguished. The ideas that sympathetic- ally excite the sensorj'^ cells are either the ideas actually present in consciousness at the time, or the ideas that are psychically latent — i.e., more accurately expressed, the material disposi- tions that still lie below the threshold of consciousness. In the first case the hallucinations correspond to the momentary content of consciousness ; in the second case they emerge from among the latent ideas very suddenly, surprising even the individual himself, it is evident that in general hallucinations of the second class occur only when very considerable changes in the excitability of the sensation-cells have taken place, while the actual conscious ideas produce hallucinations even when the excitabilit}^ of the sensation-cells has but very slightly increased. For this reason hallucinations of the second class are generally much more vividly perceived than those of the first class, since in the former class the sensation-cells are more affected by the morbid phenomena than in the latter." If we assume that the sensation-cells are those cells which form the ultimate receptacle for ingoing impressions wo must make them responsible for the direct transmission of physio- logical activities into presentations in consciousness. It would seem, from the remarks of Ziehen, that even though currents may pass through these cells, by way of association-paths to other regions (" memor3--cells "), j'et, in order that these cur- rents may ultimately manifest themselves in consciousness, they would have to return from the said memor^^-areas to the sensation-cells. If backward currents proceed to sensory cells, A\hicli are morbidly affected and irritable, and which intensify or pervert the functional activities propagated to them, we may reasonably assume that, if the same sensory cells are concerned with the transmissioii of stimuli which pass forward, and the reception of stimuli which are supposed to pass backward, then these same sensoiy cells must be affected in a way that allows perfectly normal processes to go on in one direction but not in CLINICAL CONSIDERATIONS. 263 another. Hitherto, it has not been demonstrated that sensory cells are morbidly irritable in hallucinatory states, and we do not believe that hallucinations necessarily depend upon any hyperajmia of the sensory cells. Let us, however, further ilkistrate our position by a simple diagram. The sensation- ■cell is thought to be morbidly affected, so that currents passing from M are morbidly intensified — that is to say, the currents ( • ^Presentation O jSensation-Cell ^(oj Memory Cell p I O J Periphery Fig. 15. transmitted backwards from the " memorj^-cells." through the association-path M S, become intensified owing to the patho- logical state of S ; in reality, however, we know that, even with the most gi'oss hallucinations of the insane, normal currents can be transmitted along the line P S and thence along S M, or they may arrive intact in their normal operative- ness at the region apposite to the mental occurrence. Clinical Considerations. — Baillarger pointed out that visual hallucinations are more frequent than auditory in healthy life, but that in disease the auditory are the more frequent. The comparative frecpiency of the occurrence of sensory perversions is of interest, but we cannot devote much space to it here. Escjuirol found that 80 out of 100 insane patients had hallucinations. Brierre de Boismont found 38 out of 62 patients. The following table is constructed from the records of the last 1,000 cases admitted to Bethlem. In many of the cases it was difficult to determine whether the perversion was mainly illusory or hallucinatory, so that the numbers may be regarded merely as indicating sensory perversions. 264 HALLUCINATIONS. From ail analysis of the said 1,000 cases admitted to Betlilem Hospital, it was found that sensory perversions were present in the following order:- — Hearing _ _ _ _ 506 Sight ----- 359 Common Sensation - - 221 Smell ----- 194 Taste ----- 161 From, the previous history of the patients, it was ascertained. that during the earlier periods of the attacks the perversions were as follows : — Hearing- 567 Sight 510 Taste - 254 Common Sensation - - 213 Smell - 191 It was also found that before admission 159 had had no sensory perversion. 303 „ ,, one sense affected. 299 „ ,, two senses ,, 150 ,. ,, three ,, ,, 62 ,. ,, four ,, ,, 27 ,. „ five Oh admission and during their stay in the hospital 292 had no sensory perversion. 297 „ one sense affected. 219 ., two senses 100 „ three ,, ,. 57 .. four ,, ,, 35 „ five ,, ,. Of those who had two senses affected, the commonest com- binations were those of sight and hearing, and smell and taste. When three senses were affected, the combinations were com- monly sight, hearing, and common sensation, or smell, taste, and common sensation. In order that we may more fully appreciate the influence of the various senses and their perversions of function in the pro- duction of morbid perceptual processes, we must now devote our attention more particularly to the consideration of the special PERVERSIONS OF TASTE. 265 senses themselves in their morbid aspects ; and, first of all, we discuss the various perversions of taste. Perversions of Taste. — We have already considered the different gustatory qualities and their relation to after-tastes and secondary olfactory sensations. The subjective gaistatory im- pressions amongst the insane are ver}' frequently due to pathological causes, arising either peripherally or centrally. Thus, diseases of the tongue, as well as dryness of the mouth,, caused by interference with the salivary secretion, may interfere with the sense of taste. The administration of morphia hypo- dermically is sometimes attended b}- bitter or acid tastes. Briefl}', the various perversions may be described as occurring in the form of (1) hi/perr/eiisia — exaltation of the sense of taste. i.e., there is a morbid exaggeration of all gustatory sensations,. as seen in some forms of neurasthenia, extreme nervousness.. and sometimes even in conditions of mania or melancholia. (2) Hypogeusia — diminiition of the sense of taste. After ice has been sucked, there is often a diminution ; as also in acute' maniacal or melancholic states, in cases of stupor with general blunting of the sensibility, and in general paral}'sis of the insane, where there is often a marked loss of perception of flavours and tastes. (3) A. 610. rEKVEIfSlOXS OF THE MUSCULAR SENSE. 283 "would be disported to think that the starting point was irrita- tion of the auditory nerves or auditory centres. He believes, hoAvever. that it may be admitted, that in the acute form of paranoia the whole nervous system is in a state of extreme excitement, and that there may be hallucinations both of the miiscular sense and of other sensorv nerves, as well as motor incitations to the muscles of the voice. Klinke * agrees with Cramer's explanation, and believes that abnormal sensations in the tongue and throat ma}' arouse delusive fancies leading to derangements of speech. Sometimes these take the form of babbling and childish sounds, or the patient complains of distress and difficult}^ in speaking, accom- panied by a feeling of constriction in the tongue or throat. The muscular sense is said to be increased in somnambulistic and hypnotic states. The condition known as anxiefas tiliiarifin, in which there is a painful condition of unrest leading to continued change in position of the limbs, is considered to be due to abnormal increase of the muscular sense. Diniiiintloti occurs in some choreic and ataxic persons. The sense of movement (kliuestliesls) has received so much attention, and there are so many differences of opinion with regard to it, that we must, before concluding this chapter, review in brief some of the leading discussions. Bastian be- lieves, that impressions of various kinds combine for the per- fection of this sense of movement, and that in part its cerebral seat coincides with that of the sense of touch. He includes lender this " sense of movement,'' as its several components, {a^ a set of conscious imjoressions of various degrees of definiteness — viz., cutaneous impressions, impressions from muscles and other deep textures of the limbs (such as fascifB, tendons, and articular surfaces) ; and, in addition, (li) a set of " unfelt " impressions, which guide the motor activity of the brain by the information (unconscious) which they afford as to the different degrees of contraction of all the muscles concerned in the production of anj- given movement. " The occurrence of movement is for the kingesthetic sense what the presentation of an external object is to the visual sense ; and the inability to cognise the impressions occasioned b}^ movement (either those that are conscious, or * " AUgemeine Zeitschrift fiir Psychiatrie," xlviii. Band, 1 and 2 Heft. 284 HALLUCINATIONS. those that are unconscious, or both), which is sometimes produced by certain morbid conditions of the spinal cord or of the brain, is a defect of the kineesthetic sense altogether analogous to amblyopia or blindness in relation to the visual sense/' * The relation of the kintesthetic sense to volition will be discussed later. Here we have to consider only those elements which go to make up the so-called kingesthetic sensations, and the first question v/e have to ask is, Do cutaneous impressions — impressions from muscles and other deep textures of the limb (fasciee, tendons, etc.) — actually exist; and, if so, are they all essential to the formation of a kinassthetic per- cept ? That cutaneous impressions and impressions from articu- lar surfaces do exist there can be no doubt. Duchenne f has pointed out, that in patients with cutaneous ansesthesia of a limb, the muscles of which are not sensitive to faradic stimu- lation, there may still be preserved a very accurate sense of the \^'ay in which the limb may be flexed or extended by the hand of another. Eulenberg J assumes that the articular surfaces are the seat of the perception of movement. The sense of move- ment ma}'' be impaired when the tactile se^isibility is preserved. James points out, that the pretended feeling of outgoing inner- vation obviously plays no pai't in these cases, from the fact that the movements by which the limb changes its position are passive ones, imprinted on it by the experimenting physician. That the joint surfaces are sensitive appears evident, according to James, from the fact, that in inflammation they become the seat of excruciating pains, and from the perception by everyone who lifts weights or presses against resistance, that every in- crease of force opposing him betrays itself to his consciousness principally by the starting-out of new feelings or the increase of old ones in or about the joint. § Lewinski || records the instance of a patient, the inner half of whose leg was anassthetic. On standing \i]> the j)atient had a curious illusion that he was knock-kneed, which disappeai'ed the moment he lay down * " Paralyses: Cerebral, Bulbar, and Spinal," p. 108. t "Electrisation Localisee," pp. /'i?, 770, Leyden ; Virchows ''Archiv," 1869, Bd. xlvii. + "Lelirb. d. Nervenkrankheiten "' (Berlin), 1878, 1, -j. § " Principles of I'sychology," vol. ii. p. 191. II " Ueber den Kraftsinn." — " Virchows Archiv, " Bd. Ixxvii. 134. PERVERSIONS OF THE MUSCULAR SENSE. 285 again. In this ca.se the inner half of tlie joint probablj shared the insensibility of the corresponding part of the skin, and the feeling was just what he wonld get were his legs forced into a^ knock-kneed attitude — ?".e..the outer-joint surfaces would be more strongly pressed together than the inner. Lewinski also found in every instance that, when the toes of certain ataxic patients with imperfect sense of position were flexed and drmvn upon simultaneoiisly with the separation of the joint surfaces, all sense of the amount of flexion disappeared. On the contrary, when he pressed a toe in whilst flexing it, the patient's appreci- ation of the amount of flexion was much improved, evidently liecause the artificial increase of articular pressure made up for the pathological insensibility of the parts.* Goldscheider f has proved by a series of experiments, that the joint surfaces, and these alone, are the starting point of the impressions by which the movements of our members are immediately perceived. Goldscheider caused his fingers, arms, and legs to be pas- sively rotated upon their various joints in a mechanical apparatus which registered both the velocity of movement impressed and the amount of angular rotation. No active muscular contrac- tion took place. The minimal amounts of rotation felt were in all cases surprisingly small, being much less than a single angular degree in all the joints, except those of the fingers. The point of application of the force which rotated the limb made no difference in the result. Rotations romid the hip- joint, for example, were as delicately felt when the leg was hung by the heel as when it was hung by the thigh whilst the movements were performed. Anassthesia of the skin, produced by induction-currents, also had no disturbing effect on the per- ception ; nor did the various degrees of pressure of the moving* force upon the skin affect it. It became, in fact, all the more distinct in proportion as the concomitant pressure-feelings were eliminated by artificial aneesthesia. When the joints them- selves, however, v/ere made artificially angesthetic, the perception of the movement grew obtuse, and the angular rotations had to be much increased before they were perceptible. % * Quoted from James, "Principles of Psychology,' p. 192. t " Archiv. f. Anat. u. Physiologie," 1889, pp. 369, 540. X James, "Principles of Psychology," p. 192. 286 HALLUCINATIONS. The disorders of the sense of niovenient. as met with in the insane, are possibly to be explained as originating from the con- ditions of the general sensibility, and more particularly of the articular surfaces. Thus, general paralytics who say they have walked millions of miles (hyperkinoesthesia), or who feel that they are treading on air, have probably some change in the sensi- bility of the articular surfaces, ^\•hich act in reality as predispos- ing factors of illusory states. The sensations of flying through the air, of extreme buoyancy, or of having leaden limbs, difficult movements, etc., may all be explained from this point of view. Those abnormal subjective sensations, however, in which the body or limbs appear to shrink or expand, would l)e better ex- plained as modifications of the cutaneous and general sensibility. The considerations of the " unfelt " impressions, which are said to guide the motor activity of the brain, we leave to a subse- quent chapter. It only remains for us now to add that, in accepting the term kina?sthesis, we simply accept it as designating the sense of movement, and \\'e do not attribute to the muscular elements themselves any part in the production of that kintesthesis, except in so far as they by their action affect the articular surfaces. Illusions and Hallucinations in Dreams. — The con- dition kno\\'n as the /l!/i>nm/u(/ic state occurs when an individual is neither awake nor fully asleep. During this period the senses become more or less inactive, except the sense of hearing, which is the most persistent. The reflex activity of the spinal cord is at first somewhat exalted, owing to its being released in considerable measure from the control of the brain. As sleep becomes more profound the reflex functions of the cord are also weakened.* It is thought that, as the sensory organs retire from action, the intellectual faculties lose their equilibi-ium. First the power of volition ceases, then the logical association of ideas comes to an end, the reasoning faculty disappears, and judgment is suspended. We become, therefore, no longer capable of surprise or astonishment at the vagaries of memory and of imagination — -the onl}^ faculties that remain in action. To their more or less iinfettered activity we owe the presence in consciousness of those disordei-ly pictures which, occurring in * Rosenbach, " Zeitschr. f. Klin. Mod.," 1881. " Brain," vol. iv. p. 138. HYPNAGOGIC IJ.LUSIONS AND HALLUCINATIONS. 287 this stage of imperfect sleep, liave been termed hypnagogic hallucinations.* The following diagram, borrowed by Lyman from the " Dictionnaire Encyclopedique des Sciences Medicales," gives some idea of the successive phases during sleep : — '2 1 o '5 S o o ^ S t 1 9 6 o .So 1 Nonnal life. 1 ^^^ ^^^ u First stage of sleep— Hypnagogic hallucina- tions. ^^^ ^^^ ^H Second stage of sleep— Dreaming. n^ 1 Third stage of sleep. ^H ■ Profound sleep. w^im First stage of waking. 1 Second stage of waking — Dreams. ^B ^^^ ^^^ Third stage of waking — Hypnagogic hal- lucinations. Complete awakening. ^^^^^^ ^^^ Fig. 16. Hypnagogic Illusions and Hallucinations. — During sleep, when the subject matter supplied for the exercise of the faculties of perception and judgment, and the operations of the will, are withdrawn, the ideas that still arise are chiefly dependent for their origin and association upon the automatic and endogenous activities of the brain. Undisturbed by im- pulses from the external world, the brain seems then to become more sensitive to impressions having their origin within the body. An overloaded stomach, an enfeebled heart, a turgid sexual apparatus, or an irritable nervous ganglion, may be- * Alfred Maury, " Le Sommeil et les Reves," chap. IV. Quoted from Lyman, " Insomnia," p. 3. 288 HALLUCINATIOXS. come the source of irregailar and uncompensated impulses which, without disturbing the organs of special sense, may invade the cerebral cortex, and may there set in motion a whole battery of mechanisms, whose influence upon con- sciousness would remain quite unnoticed were the external senses in full operation.* The same author defines a dream as " the occupation of the field of consciousness during sleep by a succession of ideas more or less completely withdrawn from the guidance of the senses and from the control of the will." The possibility of suggesting to an individual who is in the hypnagogic state the nature of a dream has been often demon- strated. Thus, through the rustling of a newspaper an in- dividual has dreamt of the sounds of waves on the sea shore, and conjured up with vivid intensity the visual picture and accompaniments. Sometimes the impression produced by the di'eam is so vivid that a belief in its reality exists even some time after waking. Baillarger dreamed one night, that a certain person had been appointed editor of a newspaper ; in the morning he believed it to be true, and mentioned it to several persons, who were interested to hear it ; the effect of the dream persisted all the forenoon, as strongly as that of a real sensation ; at last, about three o'clock, as he was stepping into his carriage, the illusion passed off; he comprehended that he had been dreaming. f The step between the phenomena of dreams and those of insanity is but a ^■ery short one ; in fact, many of these pheno- mena ai'e identical in every respect. There is in both a partial displacement of the ego ; by which the " I '• which perceives the abnormal is not the "I" which was wont to perceive the normal. In artificially induced states of unconsciousness (e.g.. by chloroform) the writer has seen an insane patient who, whilst under the anaesthetic, gave vent by speech to the same delu- sions and the same train of ideas as when in his ordinary state of insanity. This fact alone was significant that the ego bore a corresponding relationship to the actual cerebral activi- ties in both states. According to Lyman, most dreams are composed of visual images. The dreamer looks upon a picture * Lyman, op. cit., p. 118. t Taine, " On Intelligence," p. 61. Quoted from Lyman, op. cit., p. 126. HYPXAGOGIC ILLUSIONS AND HALLUCINATIONS. 289 ■which changes silently before his eyes, without appealing to any other sense than that of sight. But in certain cases any other sense may become excited, prodiicing illusions or hallucinations as perfect as the images of healthy vision. They may be suggested by external impressions, or they may, at least apparently, find their starting point in accidental states of the bodily organisation. All unusual modes of dreaming, and all extraordinarj^ vividness of dream-impressions can be con- nected with some departure from the physiological conditions of cjuiet sleep. Either disease, or exhaustion, or emotional dis- turbance, or narcotic intoxication of the brain may be noted as the immediate cause of such derangement of the cerebral functions.* Maury f states that the ease with which dreams are recollected varies inversely with the depth of the sleep in which they occur. That the mind can solve problems, and perform various intellectual operations in its dream-states is a matter of common observation. The writer has on several occasions drawn upon his hypnagogic hallucinations for melo- dies and other musical ideas. The question of foresight, or actual clairvoyance, cannot be discussed here. The physiological basis of sleep is still a matter of uncer- tainty. It is assumed by most observers that there is at least a partial anaemia of the cerebral cortex. Ziehen believes that in sleep the initial element of the psychical process — the sensa- tion — is produced by "ideational stimulation j" and that the final element — the motor idea or the action — is almost entirely omitted. " The muscular system seems to be lamed ; even in the deepest sleep the phenomena accompanying the activity of the tendons, otherwise so accurate an index of the existing muscular tone, have disappeared." That motor ideas do occur in our dreams must be manifest to every one. In the fullj^-awake person the judgment perceives the natiire of the events which are manifested to the mind ; in sleep, and in insanity, on the other hand, the judgment is weak, and there is inability to perceive the absurdity and impossibility of the events which appear to happen. One point in which the dream-state differs from the insane state is to be found in the fact that, in the former a large part of the * Lyman, op. cit., p. 131. t Op. cit., p. 219, d seq. 19 290 HALLUCINATIONS. memory is blotted out, and tlie mind is unable to compare present facts with the experiences of the past ; whilst in the insane the memory for remote events is often unimpaired. Hack Tuke* points out a striking characteristic of the dreamer's mental attitude — he is usually free from the nervousness, or lack of courage, or dread of the opinion of others from which he may suffer during the waking-state. " There is an extra- ordinary change in the personality of the dreamer, to whom the loss of personal identity ceases to be strange, and he passes into the mind and body of the most opposite and improbable characters, without any sense of surprise or embarrassment." In the insane the dreams are often morbid exaggerations of the waking-thoughts. The writer has observed many instances in which insane persons have dreamt that they had the usiial forms of sensory persecution during sleep as during the wide-awake state. Hack Tuke records the case of a lady, the subject of melancholia, who was entirely free from her troubles during the night. It is not uncommon to meet with cases of insanity which have been an actual continuation of the hypnagogic state. Thus, in puerperal insanity we sometimes find that the attack has commenced with a particularly vivid dream occurring in the early morning. In a similar manner an insane hallucinatory condition may be determined by the administration of an angesthetic, such as ether or chloroform. * " Dictionary of Psychological Medicine," p. 413. 291 CHAPTEE X. MENTAL PROCESSES. Attention. Definition — Psycho-Physical Process of Attention — Psychical Theory of Attention — The Neural Processes in Attention — Monoideism — Polyideism — Reflex Attention — Voluatary Attention — Adjust- ment of Attention — Attention and Genius — Morbid Conditions — Hyper-attention — Inattention — In Mental Disorders. Conception. Definition — Concept — Psychological View — Psycho-Physical Theories of Conception — Physiological Theories — Association — Double Nature of Brain — Consciousness the Accompaniment of Nerve Action — The Theories of Discharge and Resistance. Judgment. Definition — Degree of Perfection of Judgments — -False Inductions- False Deduction — The Perception of Reality — Belief — The In- sanity of Doubt. Imagination. Definition — Differences between After-images and Imagination-Images — The Neural Process of Imagination — Morbid Conditions — Simple Delusional States — Sensory Tyi^es — Emotional or Affec- tive Types — Clinical Considerations. ATTENTION. Before taking up the subjects of " conception " and " asso- ciation " it is advisable that we should understand a little more clearly what is meant by attention. Attention is one of the most important of our mental activities, since a mental fact only exists for us in so far as we attend to it. Sully defines it as " the active self-direction of the mind to any object which presents itself to it at the moment." In accepting this defini- tion it is necessary, however, that the student should recognise 292 MENTAL PROCESSES. that the mind's consciousness of what is presented to it is not always the result of active self-direction. When we attend to a thing we intensify our consciousness by narrowing or con- centrating it on some definite and restricted area ; but were all our impressions determined only by the active self-direction of attention the mind would no longer be the passive recipient of impressions from without, and all our mental states would be determined by the primary and voluntary activity of the mind. When we force our minds in a particular direction, so as to make the objects as distinct as possible, the action involves a sense of effort self-determined ; but an unusual or novel stimulus may affect our consciousness cpiite apart from any vobintary effort of attention. In the latter condition the attention is termed reflex, and it may even necessitate a strong effort of will on our part to disengage it from the object which holds it. In the struggle for existence among stimuli the attention (or the result) is determined by the intensity or the distinctness of the sensations derived from the stimuli. It is assumed that the more intense material processes accom- ])anying the stronger sensations possess a far greater capability for awakening the images of memory, and determining the course of ideation, than those which are indistinct, confused, and wanting in intensit3\ Ziehen believes that this also explains why only the object situated in the centre of the field of vision generally determines the association of ideas, and it is just this object that produces the most intense and distinct sensation. " No apperception exercises any arbitrary control over the process whatever." Outside the regions of central focus of the attention there is always a realm of obscure or sub-conscious mental phenomena. How far this region extends in relation to the organism and its processes we are not prepared to say ; nor do we know to what extent it is modified by past ps3xhical activities. With every mental act there is a zone or halo of obscure and transitory phe- nomena surrounding the object which calls forth that act. Wundt says the whole mental region (conscious or sub- conscious) answers to the total field of view present to the eye in varying degrees of distinctness at any moment when the orL^an is fixed in a certain direction ; the latter region — ATTENTION. 293 that of attention or clear consciousness — corresponds to that narrow area of " perfect vision " on which the glance is lixed. Every sense-impression (external or internal), and every content of consciousness, when viewed by the " mental eye," is an object of attention. Thus all the phenomena of cognition, emotion, or volition may become the objects of attention. The Psycho-Physical Process in Attention.— The majority of neurologists believe that our sensations are deter- mined, not only by peripheral processes of stimulation, but also by a reflex central reaction, which in turn becomes a deter- mining cause of peripheral ingoing currents. That is to say, not only is every psycho-physical process sensory, but also motor. The ego is regarded as entirely dependent on the sensations wdiich are presented to it, primarily through the senses, or secondarilj^ through the sensations of movement or reaction. To Fechner, Bain, Wundt, Ferrier, Sully, Bastian, and others, we are indebted for many observations upon this subject. The psychical theories of attention are, that (1) the sensory presentation, or its ideational equivalent, is followed and rein- forced by a distinctively active element of attention, a third element of feeling being commonly, if not in all cases, inter- posed between them — i.e., the factors are, sensation and reaction and feeling. The reaction is regarded by psychologists as being essentially active, and involving a certain degree of voluntary attention.* (2) Attention involves detention in consciousness and a corresponding rise in vividness, distinctness, or intensity.! (3) Attention is the pure reflex of some sensory presentative process. (4) The direction of the attention involves the residua of previous experience and habitual forms of mental activity (Sully). (5) Attention involves a voluntary or consciously- selective process, which is attended by feelings of mental effort, and the sense of resistance. Wundt has tried to determine the duration of the discrimination time and the volition time in attention (" apperception "). Miinsterberg, on the other hand, contends that the whole process is mostly unconscious or sub- * Sully, "Brain," 1890, p. 148. t Eibot, " La Psychologie de I'Attentioii." 294 MENTAL PROCESSES. conscious, and that there is no room for the discriminative and volitional period.* Sully regards the result of the experiments made in Germany as being the effects of pre-adjustment, and the quasi-unconscious natiTre of the phenomena as due to the circumstance that the work of attention had been done in advance. Fouilleef also objects to Miinsterberg's explanation as inadequate, inasmuch as it is not enough that a representa- tion pre-exists in this obscure form to its clear apprehension to generate in us the feeling of activity. He points out, that just as a very distant and feeble light can approach and increase in intensity without producing that feeling, so a reminiscence, confused at first, can suddenly grow clear without any seeking or effort on our part. " Whenever attention is present we have a feeling of mental ivorJx ; of expenditure of energy." With this latter statement we do not agree. That attention to the contents of consciousness always involves a sense of effort implies the invariable presence of a volitionary force in- dependent of the intrinsic attractiveness or intensity of the sensations. Wei^e we to assiame that the imperative ideas of the insane, which thrust themselves upon the individual's atten- tion, involve a distinct feeling of expenditure of energy, we should make an assumption which would be in direct opposition to our experience. Fouillee also believes that attention is always called forth hj an emotion or an interest, by pleasure or pain — i.e., the feeling is the first stage, or, rather, "the very ground of attention." The Neural Process Theories of Attention. — Fechner, .Bain, Lewes, and others, support the hypothesis that the motor apparatus would account for the whole process of thought- control. Bain believes that every idea is composed of an element of passive and of muscular sensation. Wundt and Ward both recognise the affinity between muscular and mental exertion. Ferrier believes that attention specially involves the frontal lobes which contain some of the centres for movements of the head and eyes. Wundt postulates, that a centrifugal impulse from the centre of attention, or apperception, passes to the sensorium, and that this impulse is simultaneous and * " BeitrJige zur Experimentellen Psychologie." t "Brain," 1890, p. 351. ATTENTION. 295 organically conjoined ^yith another centrifugal process of motor innervation issuing from the same region. According to Ziehen * the feeling of attention is merely a concomitant phenomenon. The essential objective characteristic of atten- tive or active sensation, in distinction from the merely passive sensation, is the influence which the former exerts in deter- mining the choice and order of ideas hj which it is followed. In order to simplify this complicated subject we may nse a simple diagram. I may be held to represent the subjective aspect of attention as viewed by the ego within consciousness • P is the sensory surface of the cortex which presents sensations to I ; M is the motor area, from which efferent nerves pass to the motor apparatus. P' M Fig. 17. (1) Some psychologists hold, that all the phenomena of attention may be determined by the activity of I ; (2) others say that P and I are all-sufficient ; (3) others that P,I,M, is the order of events; (4) others that M,P,I, occurs; (5) others, again, that M,I,P, is the only solution ; while (6) yet others maintain that P,M, or M.P, precede and determine I ; lastly (7) others find the solution of the ditficulty in the accom- panying tone of feeling, or motive which manifests itself at I, and in turn regulates P or M. There will be found room, no doubt, for other modifications and combinations of these theories. When there is temporary j)redominance of an intellectual state, or of a group of states, the condition is said to be one of intellectual onono'ideism. This condition may arise in a spon- * Op. cit., p. 209. 296 MENTAL PEOCESSES. taneous. natural, invohmtaiy, reflex, or instinctive manner; or it may be volnntar}', active, and artificial. From a popular standpoint, the normal state of the mind is one of polyi'deisni. Attention is the momentary inhibition (to the exclusive benefit of a simple state) of this perpetual progression: it is monoi'deism. The sub-conscious states lyino- outside the limit of attention are regarded as the contents of a diffuse conscious- ness ; and, just as too great a bulk of mere retentions will often impair the process of abstract thought, so difi'use consciousness will tend to impair the process of concentration. We might formulate the law, that the intensity of a state of concentration varies inversely with the diffuseness of consciousness. An over active mind in acute states of mental disorder fails to concentrate its attention in any one given direction, owing to the rapid seriality and the diffuseness of its consciousness. Concentration presupposes an abstraction from other and external objects of consciousness, as is evidenced by intel- lectual monoi'deism. We are unable to attend to more than one thing at a time, otherwise the two objects tend to pass into the regioii of diffuse consciousness. " When an ecjual effort is made, the efiective force of an act of attention varies inversely as the extent of object attended to." " The more we comprehend or embrace in the act of attention the less penetrating will it be " (vSully). The degree of attention depends on the ciiTantitji^ of active energy disposable at the time, and the strength of the stimulus, or force which excites the attention or rouses it to action. Stimuli which arouse the attention are divided into external and internal. The external relates to the striking characteristic or attribute of the object which engages the attention ; whilst the internal means the motive which prompts the mind to exert its power of attention. In the insane, the preoccupation of the attention by morbid stimvili often renders the effects of the ordinary internal and external stimuli weak and inefficient. Thus, in the attempt to induce hypnotism where attention is an important factor, failure may be due to one of three causes — viz. : (ft) In states of difi'use consciousness (acute mania, etc.) great difficulty is experienced in the attem])t to reduce the mental states from their considera- REFLEX ATTENTION. 297 tion of the general to the particular ; (ft) in states of limited consciousness, or monoi'deism, the consciousness is ah-eady so far reduced from the general to the particular, that the reduc- tion itself acts as a deterrent to the alteration of the nature of that particular ; (c) in states of anergia or defective energisa- tion (stupor, exhaustion, etc.) the active or volitional aspect is im])aired, and there is failure in the transmission of outward motor and inward sensory currents. Reflex Attention. — The mere force of the characteristics of the object presented to consciousness is enough to determine the direction of the attention. In the struggle for existence among stimuli, the greatest, the most interesting, and the most novel tend to survive. As a rule, each survival is momentar}^, and it is characteristic of reflex attention that new stimuli can easily divert it. In conditions of morbid excitability the im- pressions are often of morbid intensity; while, in exhaustive states, there may be lessened activity of the will in determining the direction of the attention. The laivs of reflex attention are, according to Sully, determined by:- 1. The quantity of stimulus. The atti-active force of a stimulus will vary as its quantity, and more particularly as its degree. 2. The quality of stimulus. The attractive force of a stimulus depends also upon its quality — i.e., as it is agreeable, disagree- able, or indifferent. 3. The Mi-feresf taken in the object, determined by particular sensibilities, tastes, habits, etc. 4. The absolute and relative impressiveness. The ahsolide impressiveness is determined by the quantity or quality of the object ; whilst the relative impressiveness is the force v/hich the object owes to its relation to other objects which have preceded it, and to the pre-existing condition of the attention. 5. The chanr/e of stimulus. All changes, contrasts, or tran- sitions act as exciting agents to the attention. We are only conscious of an impression when we pass to it from an unlike impression. A certain frequency of transition is, therefore, essential to a state of mental wakefulness. 6. The effects of novelty. Those objects which are familiar 298 • MENTAL PROCESSES. to lis, and often recur to consciousness, do not succeed in rous- ing the attention with the same degree of force as objects which are novel. 7. Familiarity or interest often succeeds in arresting the attention. Thus, for example, in visiting a foreign country, familiarity with the events of its history, or knowledge, pre- viously acquired, of its politics or customs, will render every object of more interest. The interest displayed is often an indication of the character of the knowledge of an individual. Volkmann says the absolutely new does not chain the attention. The amount of expectancy or pre-adjustment of the attention often causes a shortening of the process of reception and recognition. Voluntary Attention. — Voluntary attention has been compared to the process of artificial selection, and reflex atten- tion to that of natural selection. The will is regarded as supplying the internal motives, which may counteract the effects of external stimuli. In this way it supplements the forces of reflex attention. According to Sully, the mind, through an exertion of will, is able to choose the quarter to which to direct its glance, and is no longer at the mercy of the most powerful external forces. Just as we can lead a horse to the water, but cannot make it drink, so we may force the mind to look at an object, but we cannot compel its fixation upon that object unless there be something of prevailing interest about it, which, by its intrinsic attractiveness, succeeds in furthering our efforts. It is utterly impossible to continue to concentrate attention upon any object for more than a few seconds at a time. We can focus our thought for a moment, and adjust our apparatus to further or facilitate the process of concentration; but, in order to keep the object within the field of distinct con- sciousness, we have to perform a succession of distinct efforts of recall. Let the student focus his attention upon some object near at hand. He will find, that when he first looks intently at the object he notes its character and dimensions ; then almost immediately he becomes conscious of objects which occupy the zone of diffuse consciousness outside the field of distinct vision ; next he reflects upon the character of the act he is performing, and realises that he himself is subjectively contemplating an VOLUNTARY ATTENTION. 299 external object; and, finally, he discovers that his mind has wandered from its original object, and to correct this he again, by voluntary effort, re-adjusts his attention. James points out that it is not an identical object in the psychological sense, but a siiccession of mutually-related objects forming an identical topic only, upon which the attention is fixed. " No one can possibly attend continuously to an object that does not change." Helmholtz agrees with this view, and believes that we cannot keep our attention steadily fixed upon a certain object when our interest in the object is exhausted ; but that we can set our- selves new questions about the object, so that a new interest in it arises, and then the attention will remain riveted. That this is true of sensory states is apparently evident, and we shall find it to be equally true of intellectual states. Thus, we see that with every voluntary act of attention there is involved a distinct sense of effort, and this more especially in its early stages before the habit has been acquired. When there is any falling-off in vigour, through fatigue or disease, the effort is greater, and attended by a greater expenditure of energy. The available quantity of energy determines the extent to which mental exertions may be carried. Beyond this point, protraction of effort involves tension, and, later, strain. Several writers have stated that there is no such thing as over-strain, but very little experience justifies the conclusion that the over-use of the faculty of voluntary direction of effort is productive of certain forms of insanity, and that the mind, just as the body, may be impaired hj excessive use of its functions. The adjustment of attention depends upon (1) the characters of the object itself. Impressions of moderate intensity are, in general, more easily attended to than those of very great or very little intensity. Very powerful impressions in general require a greater effort of adjustment than moderate ones. Very feeble ones require a greater effort also, but for a different reason — namely, in order to raise them above the limit of distinct con- scioiTsness (Sully); (2) it depends upon the preceding state and direction of activity of the attention- — e.g., in preoccupied states ; and (3) upon the ability to arouse the attention by an internal or volitional act — e.'inal intensity, the quantitative and qualitative phenomena of the impression. The feeling of resistance must of necessity PSYCHO-PHYSICAL THEORY. 337 acconipauy qualitative as well as quantitative conditions. Otherwise we grant to the mind a power of discrimination dependent upon its own laws and not upon those of matter. The so-called latent mental image is thought to be stored somewhere in the cortex, and Ave imagine possibly in the nerve- cell or its ramified processes. It is customary to speak of and imagine the physiological substratum of, say a sensory impres- sion, as an arrangement of molecules upon which is stamped the equivalent of the latent image. The facts derived from the study of partial aphasias seem to demonstrate that some parts of the coi'tex are concerned with the registration of images of memory ; but we do not, as yet, know what elements in that cortex are intimateh^ concerned with the process. If we look at the nerve-cell with its complicated branching processes we cannot point to any part of its structure and say, that at that position is the molecular counterpart of a stored image. Nervous tissues are subject to the constant changes brought about by nutrition, metabolism, etc., and it is difficult to understand the permanence of the material counterpart of the mental image in spite of the changes which the tissues undergo. This difficulty, however, is of little importance as an argument against the view that physiological modifications do remain as the physical equivalents of memory images. We all know how a scar may remain through life ; and, moreover, just as we may have an acquired motor act, such as swimming, retained through a long period of life, due to the physiological disposition of the motor nerve-cells, so it is conceivable we may have retention of the higher nervous dispositions which have more intimately to do with raemorj-. Another difficulty, which has been urged by some authors, is to find room for all the memories of a lifetime. Should the student desire to form an estimate as to how many material dispositions he ought to provide storage for, he must first recognise that no one mental impression is the exact counter- part of any other, and that, therefore, each impression must have its own material basis from the beginning to the end. No modification of a former impression, by a new impression super- imposed upon it, can interfere with that first impression, which remains as it was in the first instance, and can be reproduced 9'2 338 MEMORY. only as such. Every presentation is dependent upon a physiological process, and every representation necessarily depends npon a repetition of the process which at first gave it rise. The problem, therefore, becomes to find room for the material processes upon which the revival of the entire contents of memory would appear to depend. The inability on our part to conceive how the accommodation is affected must not, how- ever, be regarded as giving support to the argument of any metaphysicians who might advocate that the brain is unequal to the task. The connections among the brain-elements are infinite, and if a single germ possesses the organic and latent mental characteristics of the parents, what limits are there to the possibilities among the millions of cells of the brain ? During the course of a da}^ mental images succeed each other so rapidly that the task of estimating their number woiild be found quite impossible. Some authors maintain that the recall of an image is a re-creation, really a new presentation, not the old image. Baldwin says that we never have the same representation twice. This would lead us to the conclusion that the more we draw from the stores of revivable images, the more we add to the dispositions which are capable of revival. That is to say, when we experience the revival of an image the material disposition upon which the revival depends does not alter in itself, and, inasmuch as no reproduction of the primary image is the exact counterpart of that primary image, each revived image must have an equivalent organic state which remains as the latent mental image of a revived image. The relation of the primarj^ image to the revived image would appear to be as follows : — (1) The primary image is associated with a physiological impress or disposition which may be regarded as substantially persistent. This would agree in part with Aristotle's doctrine of material residues. The revivability would appear to be due to certain only partly explained laws of psychological and physiological habits. (2) Before the image is revived it entirely disappears from the mind. According to the Herbartian theory, it falls below the threshold of consciousness, but still enters as a factor in the complex whole of consciousness. This, however, is a meta- physical assumption which is not susceptible of proof. It PSYCHO-PHYSICAL THEORY. 339 appears more reasonable to assume that the primary image disappears entirely, and is revived only with the activities of the physiological disposition of the primary image. (3) With everj revival of an image the conscious accompaniments of the revived image differ from the accompaniments of the primary image ; hence it is that the revived image appears to differ from the primar}- image. (4) That we are able to recall a revived image is explained by the fact that we are able to recall the conscious accompaniments of the revived image — ej]., I see figure A on Monday and recall it on Tuesday. On Wednesday I am able to recall the revived image of Tuesday. The image of W^ednesday would, therefore, consist of A + Tuesday's accompaniments. Any change in the nature of the revived A would only be one of degree or intensity : the conscious accompaniments give rise to the appearance of change. Hence it is that — apart from the defects of memory, and the distortion of images due to toxic agents or disease — the revived image j)er se is more or less the counterpart of the primary image. The form of the primary image is not necessarily altered when revived. Such an alteration would be possible only when the actual object that occasioned the image is represented — i.e., a renewal of the actual impression by the presence of the object would be in reality a new presentation. In the various accounts of the pathology of amnesic defects it is generally assumed that the material dispositions of the images of memory tend to become effaced or rendered inert. Many theories have been advanced to explain how the images of memory gradually lose their intensity. Hitherto, however, the consideration of the laws of association of ideas has been the only method which has served to partially explain some amnesic defects, and this desiderates a psychological rather than a phj^siological explanation. Before we can hope to arrive at definite conclusions as to the nature of memory Ave must determine (1) whether the brain- tracts excited by the events proper and those excited in their recall are the same or in part different from each other ; and, first, before we can do this, we must ascertain more as to the nervous structures involved by the events proper; (2) how far memory is conditioned by the number and persistence of the 340 DISORDERS OF MEMORY. various brain-paths ; (3) what structures in the cortex are more intimately concerned with the registration or storing of the physical equivalents of mental images. When we have obtained more light upon these subjects, then, possibly, we may advance a step and endeavour to offer some explanation of the psycho- logical facts of suggestion, association, and contrast. DISORDERS OF ME3I0RY. Forgetfulness is regarded as an equally-important func- tion with remembering, and in the construction of a good memory the art of forgetting is essential. James says, that •■ selection is the very keel on which our mental ship is built." Undoubted!}^ there are many dangers in forming too many paths of recall. Ebbinghaus has tried to establish a numerical relationship between the amounts remembered and those foi'gotten, and has given the following law : " The quotients of the amounts retained b}^ the amounts forgotten are to each other inversely as the logarithms of the various periods of time that have elapsed." Just as memory is one of the first of the mental faculties to be developed, so it is one of the first to undergo impairment in old age. The culminating point of mental development is held to be at the period when there is loss of the power to build up new acqi^isitions. The decline of memory has been divided into different stages. The most recent, and, therefore, the least organised, associations are the first to give Avay. In mental diseases, just as in disorders which involve loss of memory for words, those kinds of words which are least organised are the first to disappear. Locke described two main defects in memory — viz., oblivion or want of tenacity and slowness, or want of readiness in repro- duction. From a psychological point of view disorders of memory may be classified as conditions of (1) amnesia, loss of memory ; (2) hypermnesia, exaltation of memory ; (3) para- mnesia, illusions of memory. Of these classes the various forms of amnesia are the most important. The following is perhaps the most convenient method of classification.* * Ribot, " Diseases of Memory." AMNESIC STATES. 341 Amnesic States: — 1. Conr/enital defects. 2. Conditions of temi)orary loss. (a) In epilepsj', etc. (h) Following injury or shock. (c) In acute mental disorders. 3. Conditions oi' periodic loss. (a) In states of double consciousness. (A) In somnambulistic states. 4. Conditions oi proijressive loss. (a) In general parah'sis of the insane. (/>) Associated with various brain lesions, (c) In senile dementia. 6. Conditions oi partial loss. (As seen in loss of memory for numbers, music, sounds, names, agraphia, aphasia, aphemia, word- blindness, and Avord-deafness, etc.) Hypermnesic States: — 1. Congenital. 2. Temporary, 3. Periodic. 4. Partial. Paramnesic States : — 1. Simple states. 2. By association or suggestion. 3. Bj^ identification. Amnesic States. — Coiujenital defects of memory are met with in idiots, imbeciles, and cretins. The memory ma}' be deficient generally, and the individual fails to register impres- sions ; hence there is failure in intellectual develoi^ment. Ribot is inclined to the belief that a careful stud}^ of the mental symptoms in idiots would enable us to determine the anatomical and physiological conditions of memory. He states that memory is dependent upon the constitution of the brain, and that in idiots and imbeciles the condition is abnormal. As a general rule the memory in idiots and imbeciles is unequally developed, and it is not uncommon to meet with 342 DISOHDERS OF MEMORY. partial developments in a special direction associated with absence of memory in other directions. Temporary loss of memor^^ is found in every grade, in both the sane and the insane. The amnesic state may last only for a few minutes, or it may remain for several years. In epileptic states the most characteristic instances are to be foiind. Ribot regards the three forms of epilepsy — viz., r/rand mal, petit onal, and epileptic vertigo, as different degrees of the same morbid state ; and he points out that the more moderate the attack in external manifestations the more fatal it is to the mind. Such states have been designated as mental autoinatisni (Hughlings- Jackson).* Two hypotheses have been advanced to account for the period of mental automatism — viz. : (1) The period is not accom- panied b}^ consciousness, so that nothing can be rejDrodnced ; f or (2) consciousness does exist, but in so weak a form that amnesia ensues. J The latter view finds most favour with psychologists. Certain cases of mental automatism are very closely allied to dream-states, in which a person may answer questions rationally, having, however, little or no after-conscious- ness of the events. The explanation of the loss of memory for dreams has been thought to rest in the fact that the states of consciousness during dreams are extremely weak. Magnan§ has recorded the case of an epileptic who was alcoholic. The patient, when seized during the day with an epileptic attack, broke everything within his reach, and was verj^ violent. At nio-ht time he had alcoholic delirium, with the characteristic terrifying visions. The following day, on coming to himself, he remembered the delirium of the night, but had no recol- lection of the delirium of the day. Falret has pointed out. as a very important characteristic of epileptic mania, that the mental condition is surprisingly uniform in the different attacks. To the well-known views of Hughlings- Jackson — that mental automatism results from over-action of low nervous centres, because the highest or controlling centres have been put out of use — we shall have occasion to return, so we now * '• West Riding Asylum Reports," vol. v. p. 116, et seq. t Morel, "Traite des Maladies Mentales," p. 695. X Ribot, " Diseases of Memory-," j). 73. § "Clinique de Sainte-Anne," March 3, 1879. AMNESIC STATES. 343 pass to those forms of temporary amnesia which follow upon an injury or shock. After an injury or shock the amnesia may begin imme- diately, and continue for a longer or shorter period ; or it Inay extend backwards, and include recent or remote events. According to Ribot, it more commonly extends both backwards and forwards. There may be, or there may not be, recover}^ from the loss. Sometimes re-education is required. It is assumed that either the registration of anterior states is interfered with or effaced ; or, if persisting, their power of revivification by association with the present is destro3^ed. Numerous instances are recorded in which, through injury or shock, the immediate antecedent events have been entirely effaced from memorj^ A blow on the head, a fall, a fever, or an acute illness may produce like effects. There is a considerable amount of difference of opinion as to the states of memory in acute mental disorders, Clouston advises us to be careful in predicting in states of mental exaltation. He believes that the memory of events, during the disease, is regulated by the degree in which the power of attention is unaffected. Unfortunately, however, it is often difficult to apply the principle practically. Some patients appear to take little or no notice of their surroundings, or of the ordinary occurrences which take place around them ; but on recovery they will often tell you that they noticed every- thing, and, moreover, their memory may be exceedingly good. More commonly, however, they are apt to distort and exag- gerate what has happened to them during their illness. Savage believes that memory begins to fail naturally, in cei"tain particulars, at about middle age ; and that memory of names, of persons and places, and the like, fails in most busy men soon after forty years of age. This he regards as physio- logical, and as due to two causes — viz. : (1) The middle-aged man has found the futility of collecting matter not likely to be required later ; he has not the same special interest, and does not pay the same attention to new names and faces that he did when a younger man ; (2) there is a limit to the storing capacity of the human brain for disjointed, disconnected facts. Frequently the question arises as to whether a person ought to 344 DISORDERS OF MEMORY. be detained in an asylum simply on account of defective memoiy. Savage believes that this is often the kindest and best treatment, especially with old people, who are likely to require constant attention and control. Similarly, a person who has no recollection, but has, nevertheless, desires and appetites, is a person pretty sure (especially if a \\'oman) to get seriously compromised, and, if she have money, to be injuriously influenced, when under no care whatever. In cases of stupor, a distinction has been made between the anergic and the onelancholic, in that the former is attended with loss of memory, due to absence of consciousness ; whereas, the latter variety is said usually to imply a memory little affected. This distinction, however, is not always satisfactory, and numerous instances occur in which the memory is unimpaired, even in what have been described as typical forms of anergic stupor.* Bevan Lewis has described the amnesic form of alcoholic insanity, in which there has, or has not, been delusional perversion. He regards the amnesia as the earliest evidence of structural change, and believes that absolute recoverability is rarely (if ever) obtained in this stage of alcoholism. This, however, is not cpiite our experience ; from which we have been led to conclude that the incurability of the amnesic form of alcoholism is not alwaj^s to be assumed. But if some do not recover, we have, on the other hand, seen alcoholics regain their memory in a most remarkable manner, and leave Bethlem Hospital with little or no trace of their former inability to register or recall impressions. Bevan Lewis states that the revivability of a former impression, as a resultant, depends upon (1) the intensity of the previous impression ; (2) the vigour of circulation and nervous energy ; (3) the organisation of such impressions in the establishment of associated sense-impressions ; (4) the vigour of the faculty of attention ; (5) the element of time. He says : — " The intensity of the previous impression appears to be of minor importance, but the vigour of circulation, and of nervous energy, is decidedly at fault. . . The conduction along the nervous circuit is impeded in such cases, as proved by the retarded response made to sensory stimuli, visual and auditory; and this we have more reason to * Newington, "Journ. Ment. Science," Oct., 1874. AMNESIC STATES. 345 attribute to delay in the seiisory arc than in the motor arc, or it may be due to delay in the transference Irom the one to the other. Such sluggish transmission can only be regarded as resistance in the nerA'Ous arc, and as resulting in a diminution of the effective force of the original impact at the periphery. Hence it is that the organisation of such impressions by the establishment of associative links — i.e., the forcing of new nervous tracts into adjacent areas — becomes greatly impeded, since this greatly depends upon the vigour of the nervous current and the vascular supply of the part Such organisation is greatly aided by the faculty of attention, which, when directed towards the impression we tend to revive, fosters the growth of that associative process whereon a persistent and efficient memory is based. Thus it is that slight distraction of the mind, even momentarily, by directing the attention to any other line of thought, will abolish the feeble tendency to organisation of the original impressions which might otherwise occur."* In all explanations of this kind, one can well tinderstand the employment of such expressions as " resistance in the nervous arc," " forcing of new nervous tracts," etc. ; but it must be remembered that such expressions are merely symbolical of hypothetical physiological accompaniments of mental events. According to Ribot, this form of temporary amnesia is characterised psychologically by the fact, that it appears only in the less automatic and less organised phases of memory. He believes that in cases' belonging to this morbid group, neither habits, nor aptitude for mechanical work, such as that of sewing or embroidery, nor the faculty of reading, writing, or speaking a native or foreign language, are in the least affected ; in a word, memory, in its organised and semi- organised form, remains intact. It is commonly assumed that temporary amnesia aifects onl}- the most highly developed and recent unstable mental attainments. This, however, is not invariably the case. Thus, for example, I have known an individual whose memory for recent events was comparativel}' good ; he nevertheless was unable to recall his own name. We are all familiar with such an experience, and can no doubt narrate instances in which, owing to some slight emotional cause, such as shock, or nervousness, the memory for highly organised events has disappeared temporarily. The physiological explana- tion of this psj^chical fact is as yet unsatisfactory. The temporary loss of the most recent acquirements is thought to be due to * "Text-Book of Mental Diseases," p. 310. 316 DISORDERS OF MEMORY. loss of the faculty of registering the latest impressions. This, however, aiFords no exj)lanation as to the obliteration of what may be regarded as long assimilated and stable acquisitions. In some instances of extreme rapidity of re-education, it has been thought possible that the memory returns because the atrophied nervous elements are supplanted by other elements having the same properties, primitive and acquired, as those which they replace. This ma}^ possibly account for the re- education, but it cannot account for the rapidity of the process. We can readily conceive that new elements may take on the functions of old ; but the re-education often means the recol- lection of impressions which have been conserved and reproduced. This, if the case, would involve restitution of the former ac- quisitions, revival of the old physiological dispositions, and not necessarily the opening out of new tracts to displace the old. Periodic loss of memory is a subject which has provided us with occurrences of extreme interest and importance. Under this heading may be included the phenomenon of " double consciousness." In such conditions an individual may have a perfect dual existence, so far as the continuity of conscious events is concerned. The instances of alternation of two personalities may for convenience be divided into two main groups according as the alternation is complete or incomplete. In comiilete alternation the personality of the individual is entirely different in the two states ; there is no continuity of thought, and the memory of one state is absent diiring the occuri'ence of the other. A female patient admitted to Bethlem four years ago had such complete alternation that for a period of twenty-four hours she was depressed, thought she was being burnt, and failed to recognise people around her. Then during the next twenty-four hours she was natural and Ijright mentally, recognised those around her, but had no memor}'- of her experiences on the previous day. Another patient (a male) for several weeks had alternating conditions. One day he would say, " Now then, my lads ! bustle up and get me a good breakfast, feel as if I hadn't had food for a Aveek." When asked if he had ever been miserable, he would say, "Never known a moment's unhappiness in my life " ; and when questioned as to his present state of mind, he invariably replied, " I'm as fit as a fiddle, AMNESIC STATES. 347 hearty as a buck, and as jolly as a sand-boy." During the period of happiness he would laugh, converse with everybody, and eat ravenously. The next day, however, a change A^ould come over him: he would lie in bed, moaning incessantly, grumble at everyone, refuse food, and say that he had never had a happy moment in his life, and always suffered the ''tortures of the eternally damned." In this case the alternation could not be said to have been complete, inasmuch as he, in both conditions, recognised and called by name the attendants who looked after him. His memory of the two states, however, was always disconnected. Azam considers that in dreamirig, the mind, deprived of the co-oi'dination of ideas and the action of the senses, represents a personalit}^ different from the same in the waking state ; a personality which is often considerable though incomplete. Similarly, he believes that the drunkard has two lives ; his ordinary state and the state of drunkenness, during which latter he may act with an appearance of reason. An intellectual and highly cultivated lady was recently admitted to Bethlem suffering from melancholia with anergia. Her father was alcoholic ; otherwise, her family history was good. Three years previous to her admission she became somnambulistic. She used to make a great noise during the night by banging at her door, shifting furniture, etc. At times she would bump her head on the floor, but never really to hurt herself. During her somnambulistic state she would answer questions intelligently and to the point. When com- paratively free from somnambulism she suffered in other ways — e.g., from indigestion and symptoms of gastric ulcer. Under treatment by hypnotic suggestion she improved somewhat ; but subsequently relapsed into her somnambulistic habits. Two years from the onset of her first symptoms she began to write letters during the night. These letters were badly written, and onlj^ faintly resembled her ordinary hand- writing. Subsequently she would do and say things during the day time, of which she had no recollection when in her normal state. Again hypnotic suggestion was tried ; but it was found that after the experiment she could not be roused for a period of nearly six hours. When in her normal state of wakefulness she failed to recall any of the events of her somnambulistic state. During the latter state, on 348 DISORDERS OF MEMORY. the other hand, she could give a connected account of her waking state. Subsequentlj- she developed a third state, somewhat resembling petit mal, during ^\'hich she would steal and hide things which did not belong to her. Azam has advanced the hypothesis that dual conscious- ness is only complete somnambulism, or ambulatory auto- matism. He believes that the successive awakening of the faculties and of the senses constitutes a gradation from ordinary sleep to complete somnambulism, ^^'hich gives to the person studied the appearance of leading a dual life. ''We may meet persons who ha^'e the appearance of being like everyone else and who yet, being in the second condition, are only somnambulists, who on awakening will have forgotten everything." Many of these c[uestions are clearlj- oiitside our subject, so that we are unable to discuss them here. The medico-legal aspects of this cjuestion, however, are of such importance that we cannot do better than quote the words of Azam, who says : — " We do not hide from ourselves the disturbing questions which this possibiUty justly raises, especially from the point of view of responsi- bility. But it is not the business of science to inquire into the conse- quences of what it affirms. Its duty is at the same time a grander and a more narrow one. It is to establish the truth, basing itself on certain well-established facts. Let us carry ourselves back to the times when they burnt hysterical women as witches, because, being ansesthetic under the lash, they were, it was said, in league with the Devil. " To-day we shrug our shoulders. Will our descendants not shrug theirs in their turn at a period when, considering the inevitable law of progress, our successors will be able to give explanations which we cannot do at the present day, and when that which astonishes us now will astonish nobody ? " Let us content ourselves with registering the facts, after having carefully observed them ; others will draw conclusions from them better than we can. " Then, perhaps, magistrates and physicians will keep pace with the progress of science : they will be better acquainted with the singular states that may render criminals irresponsible, and they will foil the trickery of those who, knowing that these states exist, will simulate them to procure a verdict of * Not guilty,' as also tlie exaggerations of the lawyers, who will make the most of them for their purpose. Then, perhaps, there will be compiled for all physicians a forensic medicine in keeping with the progress of physiology and psychology. At present this does not exist." "■' * Azam, "Take's Dictionary," p. 406. MEMORY IN HYPNOTIC STATES. 349 In connection with the evohition of two separate personalities in the same individual the very important question arises, Wliat is the mechanism which permits of the evolution of two distinct series of associations, which in themselves are complete, but which have no community with each other? We are qtiite unable to answer this ; we can only make vagiTe suggestions as to alternate actions of the two hemispheres, or venture upon Iwpotheses which, in the present state of our knowledge, it would be impossible to verify. Memory in Relationship to Hypnotic States. — According to Professor Beaunis, of Nancy, the following laws regulate the hypnotic memory: — (1) The memory of states of con- sciousness (sensations, acts, thoughts, etc.) of the hj'pnotic sleep is abolished on wakening ; but this memory can be revived by suggestion, either temporarily or permanenth'. (2) The memor}^ of states of consciousness of the hypnotic sleep reappears when hypnosis is again induced ; but this memor)' can be abolished by suggestion, either temporaril}^ or permanently. (3) The memory of states of consciousness, of the waking state and of natural sleep, persists during the hypnotic sleep ; but this memor}^ can be abolished by suggestion either temporarih' or permanently. These laws refer to cases of deep hypnosis only. Memory in relationship to hypnotic states varies widely in accordance with the depth of the hypnosis and the varying personality of the subject operated on. In slight hypnosis there is apparently little or no alteration in memory; the subject remembers during hypnosis the events of waking life, and on passing into the normal condition easily recalls all that has happened during hypnosis. In somewhat deeper stages, on awakening the memorv of what has taken place during these stages is less distinct. The subject will then frequently state that he can recall all that has been said to him and that he heard every- thing. On questioning him, however, it will generally be found that he remembers very little, and that what he has been able to recall fades rapidly. In the deepest stages the subjects can recall nothing on awakening, and to this condition the term somnambulism is usually applied. The proportion of hypnotised persons who pass into this condition may be roughly stated as about 20 per 350 DISORDERS OF MEMORY. cent. When a hypnotised subject is unable to recall on wakening anything that has passed during the hypnotic con- dition the lost memory is very rarely revived spontaneoiisly. A few instances of this are recorded, however, both in the normal waking state and in dreams during natural sleep. This amnesia after hypnosis is sometimes reached in slight hjqDnotic con- ditions, when alterations in the voluntary muscles can alone be induced ; in other instances it is absent in the deeper stages, characterised by alterations in the special senses. One subject, for example, may be unable to recall on awakening that the muscles of his arm had been rendered stiff during hypnosis, while another may remember distinctly a sensory hallucination or recall perfectly all the steps of a painless operation. The hj^pnotic memory is frec|uently more precise than the ordinary memorj^, but this improvement is manifested, as a rule, only by those subjects who have forgotten on awakening all that has passed during the hypnotic state. Many instances are recorded of marked improvement of memory during hypnosis. Bramwell has found, for example, that subjects who are iinable to recall in their normal condition events in their lives which have taken place at an earlier age than seven years were able during hj^pnosis to vividly recall what had taken place at the age of three. One j^oung girl, imperfectly educated, who could play a few dance tunes upon the piano, but who could only do so in the normal condition when she had her music before her, was able, when hypnotised and blindfolded, to play the same tunes much more brilliantly. Another patient, whose natural memory was unusually bad, and who could only learn a piece of poetry, for example, with much difficulty, was able to recall on awakening, after suggestion to that effect, some verses with which she was previously unacquainted, and which were only read over to her twice in the hypnotic condition. Professor Beaunis draws attention to the fact that certain subjects respond to suggestions when in a condition which in many respects resembles the noruial waking state. In reference to them he says: — " One can determine with certain subjects a particular state which is neither hypnotic sleep nor the waking state. The subject is perfectly awake ; he has his eyes open, and is en rapport with the outer world. MEMORY IN HYPNOTIC STATES. 351 He recalls perfectly all that is said or done around him, all that he has said or done himself, the memory is only lost upon one particular point in reference, namely, to the suggestion which he has just fulfilled ; it is by that and by obedience to suggestions that this state resembles somnambulism. These two characteristics are the only ones which dis- tinguish it from the ordinary waking state. I have given the name ' veilh somnambidique ' to this condition." Bramwell lias freqiienth^ observed the condition described by Professor Beannis, but lias found that it could only be induced in subjects who had been deeply hypnotised on some previous occasion. With some of these, without any attempt to reinduce hypnosis, he could induce alterations in the volun- tary muscles or special senses by a verbal suggestion given quietly in his ordinaiy tone of voice. Sometimes he has found that these suggestions were forgotten immediately they were fulfilled, but in many other instances the subjects recalled them perfectlj^ even after a lengthened interval. Suggestion plays an important part in hypnotic memory, and it is difficult to be absolutely certain whether any of these alterations just referred to arise quite spontaneously, without suggestion from the operator, or auto-suggestion on the part of the subject. With some subjects the first hypnosis is followed by complete forgetfulness of what has taken place during that condition, even when the operator has carefully avoided all suggestions in reference to the memory, but in such instances one can never be absolutely certain that the subject has not made auto-suggestions as the result of his preconceived ideas in reference to the hypnotic state. The recollection during the hypnotic state of what has occurred in waking life and in previous hypnotic condi- tions rarely occurs spontaneously ; in the first instance, at all events. In some cases frequent suggestions are necessary in order to obtain this revival of memory, but once induced it will often occur spontaneously in subsequent hypnoses, or, at all events, it will then be capable of easy production by suggestion. The amnesia, partial or complete, which frequently follows the termination of the hypnotic state can easily be prevented by suggestion. If it be suggested to a hypnotised subject that 352 DISOKDERS OF MEMORY. he shall be able to recall on wakening not only what is passing in his present hypnotised condition, bnt also all that will take place during snbseqnent hypnoses, it will be found that the occurrence of this amnesia has been entirely prevented, and that it A^'ill not again manifest itself unless suggestions are made with the object of creating it anew. According to Bramwell, memory in hypnosis may be : — (1) Unchanged ; (2) the subject may remember during hypnosis the events of waking life, with a clearness corresponding to his powers of memory in the normal state, and on awakening have a more or less indistinct recollection of what has passed during hypnosis ; (3) he may recall during hypnosis the events of waking life to a greater extent than he could do in the normal condition, and, on awakening, ma}' have lost all recollection of what has taken place during hypnosis ; (4) he may be unable, owing to suggestion, to recall during hypnosis the events of Avaking life or those of previous hypnoses, and, on awaken- in o-, may have lost all recollection of what has taken place during hypnosis ; (5) he may recall during hypnosis the events of previous hypnoses and those of waking life, the latter to a greater extent than he could do in the normal condition, and by suggestion this memory may be retained on awakening. In this latter condition amnesia has been prevented by suo-o-estion, and there is now no break in the memory of the hypnotised subject. The only alteration is one of improve- ment ; the subject now remembers in the waking state past events which he was unable voluntarily to recall in that condition, but the memory of which he has been able to revive in hvpnosis. He also recalls in the waking state the recent impressions he has received during hypnosis — impressions which he would not have been able to recall so vividly had they been made in the waking state. He remembers, for instance, in the waking state, the piece of poetry which has been read to him twice during hypnosis, and which he would have required to have read man}- times in the normal state in order to retain an equally clear recollection of it. It has been attempted during hypnosis to revi\'e the memory of what has occurred during the administration of LAW OF REGRESSIOiN-. 353 an anaesthetic, such as ether or nitrons oxide gas, but in the few exjoeriments of this kind with which Bramwell was personally acquainted the attempt proved a failure. The same non-success attended his attempts to revive the recollection of what had taken place during normal sleep. With one subject, whose memory during hypnosis of the events of waking life ^^'as exceptionally good, he carried but the following experi- ment : — The patient was in the habit of falling asleep every Sunday afternoon in his arm-chair, and it was arranged that on these occasions he should be read to aloud, and that the same sentences should be repeated again and again. Bramwell afterwards hypnotised him, and tried to make him recall by suggestion what had been read to him. The experiment, though frecjuently repeated, was invariably unsuccessful.* We now come to what is perhaps the most important of the amnesic conditions — namely, the conditions of i)ro(jressive loss. Ribot has postulated, that the progressive destruction of memoiy follows a certain order. His Law of Regression is, that the loss advances 'progressively from the unstable to the stahle. In cases of general dissolution of the memory, an in- variable path is followed — viz., memory of recent events goes first, then that of ideas in general, next feelings, and lastly acts. In instances of partial dissolution the loss also follows an invariable path — viz., proper names, common nouns, adjectives and verbs, interjections, gestures. It is now generally held, that in brain-degenerations the nervous elements are no longer able to store new impressions, nor is it possible to form new dynamical associations. Ribot believes, that the modiiications established for years in the nervous elements until they have become organic (" dynamical associations and groups of associa- tions called into activity hundreds and thousands of times ") remain ; and that they have a great power of resisting destruc- tive agencies. The exactitude of the law of regression is held to be verified in those rare cases where progressive dissolution of the memory is followed by recovery, because recollections return in an inverse order to that in which they disappear. That * For this account of memory, in its relationship to hypnotic states, the author is indebted to the teaching of Dr. J. Milne Bramwell, who has not only demonstrated the accuracy of his statements, but has also sanctioned the performance of control experiments upon his patients. 23 354 DISORDERS OF MEMORY. the old groups of associations are organised by being called into activity " hundreds and thousands of times " we can imagine, but we do not understand how the law of regression is to provide us with an explanation of the extraordinary revivifica- tion of certain recollections when the mind turns backwards to conditions of existence that had apparently disappeared for ever. In such instances,' the main conditions of the process of organisation (b}' repetition) are v>-anting. Ribot describes the anatomical cause of this intellectual dissolution as " an atrophy which, first invading the exterior cerebral layers, penetrates to the white substance, causing a fatty and atheromatous degeneration of the cells, tubes, and capillaries of the nervous tissue." He quotes a physiologist who says, organic life is analogous to what occurs in a great commercial crisis : " The old houses resist the storm ; the new houses, less solid, go down on every side." Such an analogy would appear to hold good in a psychical sense ; but, as yet, we are far ftom possessing any proof that one layer of the cortex more than another is concerned with the recent or remote acquisitions. We agree with Hughlings-Jackson, who was the first to demonstrate that the higher functions disappear before those which are general and automatic ; but we cannot, as yet, go so far as to locate the structures concerned with these grades of function ^^■ithin definite layers of the cortex. Before leaving this part of the subject, it may be well to reconsider some of the conditions on which conservation and reproduction depend; and this involves some account of the relation between the anatomical seat of the primitive im- pressions and the nervous elements which are active when the impressions are revived. Ribot says : — " Primitive acquisitions — those that date from infancy— are the most simple ; they include the formation of secondary automatic movements in the education of the senses. They depend principally upon the medulla and the lower centres of the brain ; and we know tliat at this period of life the exterior cerebral layers are imperfectly developed. Apart from their simplicity there is every reason why these first acqui- sitions should be stable. In the first place, the impressions are received in virgin elements. Nutrition is very active : but incessant molecular repair serves only to fix the registered perception ; the new molecules taking the exact places occupied by the old, the acquired state finally becomes organic. Moreover, the dynamic associations formed between LAW or REGRESSION. 355 the different elements attain after a time to a condition of complete fusion, thanks to continual repetition. It is inevitable, then, that the earlier acquisitions should be better conserved and more easily repro- duced than any others, and that they should constitute the most lasting form of memory. " While the adult organism is in a healthy state, new impressions and associations, although of a much more complex order than those of infancy, have still great chances of stability. The causes just enumerated are always in action, although with modified energy. But if, through the effects of old age or disease, the conditions change ; if the vital processes, particularly nutrition, begin to fail ; if waste is in excess of repair, then the impressions become unstable and the associations weak." How incessant molecular repair serves to fix the registered impression is a speculation wliich we do not attempt to make. Nor do we venture npon any hypothesis as to the physiological counterparts of the primitive acquisitions and the sum total of their revivals. We know that, in a psychical sense, first im- pressions can be localised in the past ; but we also know that revived impressions can be referred to in the past. Further, a first impression, and its series of revivals, can be referred to, and localised in time, as distinct psychical facts. This, we hold, would necessitate an additional modification or rearrangement of molecules, which would admit of the facts being reviewed and compared as distinct and separate events. How we are to explain this registration of every revival, as well as the primitive impression, we do not know. "VVe have yet to invent some chronometrical system of registration, whereby the brain-tracts, excited by the events proper, have it within their power to retain, not only the effects of the first excitation, but also everj^ subsec|uent re-excitation. To say that the first impression becomes organised by repetition conveys no real phj^siological meaning. If we assume that the structural elements become slightly modified with every revival, we have to explain how it is that the first impression as well as the modified revivals can still be referrred to. Maudsley* says : — " When an idea which we have once had is excited again there is a reproduction of the same nervous current, with the conscious addition * " Physiology of Mind,"' 1876, p. 513. 356 DISOKDERS OF MEMORY. that it is a reproduction : it is the same idea plus the consciousness that it is the same. The question then suggests itself, What is the physical condition of this consciousness P What is the modification of the anatomical substrata of fibres and cells, or of their physiological activity, Avhich is the occasion of this plus element in the reproduced idea ? It may be supposed that the first activity did leave behind it, when it subsided, some after-effect, some modification of the nerve- element, whereby the nerve-circuit was disposed to fall again readily into the same action : such disposition appearing in consciousness as recognition or memory. Memory is, in fact, the conscious phase of this physiological disposition when it becomes active or discharges its functions on the recurrence of the particular mental experience. To assist our conception of what may happen, let us suppose the individual nerve-elements to be endowed with their own consciousness, and let us assume them to be, as I have supposed, modified in a certain way by the first experience ; it is hard to conceive that when they fall into the same action on another occasion they should not recognise or remember it; for the second action is a reproduction of the first, with the addition of what it contains from the after-effects of the first. As we have assumed the process to be conscious, this reproduction with its addition would be a memory or remembrance." Professor James has pointed out that there is no conceivable o-round for supposing that with the mere re-excitation there should arise the " conscious addition " that it is a re-excitation. " The two excitations are simply two excitations, their con- sciousnesses are two consciousnesses — the}^ have nothing to do ^\■ith each other. And a vague ' modification ' supposed to be left behind by the first excitation, helps us not a whit, for, according to all analogy, such a modification can only result in making the next excitation more smooth and rapid. This mio-ht make it less conscious perhaps, but could not endow it with any reference to the past. The gutter is worn deeper by each successive shower, but not for that reason brought into contact with previous showers."' The hypothesis, that the brain-tracts excited by the event proper and those excited in its recall are in part different from each other, is maintained by some observers to be more con- ceivable than any other hypothesis. This conclusion, however, requires some explanation. We have already assumed that the difference between a revived image and a primary image (psychologically considered) is one mainly of degree or intensity- The appearance of change in the nature of the revived image LAW OF REVIVAL. 357 being due to the addition of conscious accompaniments, and to the mental complexion of the individual at the time of the revival. This theory involves the supposition that the revived image per se is in immediate relation A\ith the physiological factors which were concerned with the registration of the primary image. Further, it seems reasonable to assume that the conscious accoriipaniments of the revived imcuje occupy new tracts, which in some inexplicable way become associated with, and hold in their midst, as it were, the physiological counterpart of the re- vived image. Thus it is, that the organisation of the event proper \\-ould appear to depend upon the number of times it is revived, and. therefore, upon the number of its conscious accompaniments. It is difficult to imagine that with every revival of an image there is any actual modification of the physiological disposition of the primary image. All change depends upon the addition of new associations which would appear to have their separate and distinct functional provinces. Thus, when we endeavour to recall an incident of long ago, we frequently go back step by step recalling the accompaniments of the revived images until we are able to localise in the past the occurrence of the initial impression itself. It follows as a consequence from this, that facility in the act of recall depends in great part, not only upon the depth of the first impression, but also uj)on the nature and number of the varioiis accompaniments of the revivals. One point to be learned from these contentions is, that although the revival of an impression may depend upon the re-excitation of a formerly acquired physiological disposition, the re-excitation does not necessarily modify the primary disposition, which remains as it was. We are now, therefore, in a position to say, that when we speak of organising primitive impressions by the process of revival we simply mean, that the facility for revival is rendered more perfect by means of the additional phj- siological dispositions which have been associated with each revival. Thus it is, that althouoh the revived imao-e is in a manner born from the initial disposition, in speaking of this process of revival as a process of organisation, we really mean no more than Ave shoiild do were mc to characterise every birth, or revival in the image of man, as another step in the oro'anisation of Adam. 358 DISORDEES OF MEMORY. The inability to explain the physiological mechanism of memory does not, however, negative the law of regression from a purely psychological point of view. Clinically, it is important to note that the progressive loss of memory is usually patho- gnomonic of cerebral degeneration. In the early stages of general ixiralysis, the impairment of memory is sometimes the most marked symptom. Mickle has pointed out, that in some cases of general paralysis the impairment of memory undergoes a remission. When the remission is very marked, he believes that the impairment of memory previously existing has usually been factitious rather than real, and due more to a confusion of thought than to actual amnesia. Nevertheless, we are able to confirm his opinion that the amnesia may undergo a considerable and real remission independently of any other con- ditions. A general paralytic (a Frenchman) came to Bethlem recently, and it was found that, although formerly he could converse fluently in English, with the onset of the paralysis he could not recall any words or formulate a sentence in Eno-lish. He was, however, able to understand what was said to him in English. With various hrain lesions there is progressive loss of memor}^. Thus, in sj'philitic diseases of the brain and the meninges, intracranial tumours, circumscribed lesions due to foci of softening, heemorrhage, embolism, or thrombosis ; in chronic degeneration of the brain, due to idiopathic morbid processes, traumatisms, toxic agents, etc., the symptoms of progressive loss of memory are often marked. Sometimes the loss follows upon spinal affections, such as locomotor ataxy or multiple sclerosis ; or it may result from epilepsy, hysteria, somnambulism, chorea, paralysis agitans, asthma, exophthalmic goitre, or myxcedema. It may be determined at any period of life : thus, it is sometimes seen at puberty, adolescence, climacterium, or in old age. Various local visceral disorders determine forms of insanity in which the memory undergoes progressive degeneration ; and lastly, acute fevers, such as smallpox, typhoid, cholera, influenza, etc. ; or chronic diseases, such as I'heumatism, gout, syphilis, cancer, pellagra, tuberculosis, or malaria, may be attended with loss of memory as a complica- tion or sequel. SENILE AMNESIA. 359 111 senile amnesia, according to Bevan Lewis, the latest impressions reaching the sensorinm may be so imperfectly registered as to be rapidly obliterated, or they may fail to establish the organic connections whereby they become more permanent constituents of the nervous mechanism. He says : "• In the nexus of processes connected with, and extending around, a nerve-cell, we decipher the integration of structure upon which its permanence as a functional unit depends, and the more free such channels of communication become, the more fully organised is the structure, and the more stable and resistant to the encroachments of senile dissolutions. The latest requirements, however, are expressed in the structural modifications of the highest nervous arrangements where integration of structure is least advanced, and, unlike those associations which have been called into activity over and over again, many thousand times, they fail in that nexus of communications necessary to their stability." There will always be great difficulty in understanding how a nexus of processes becomes organised, also how this organisa- tion renders it more stable and resistant to the encroachments of senile dissolution. At present we are unable to fix the latest acquirements upon definite nervous arrangements where integration of structure is least advanced. If new routes are opened out, and new nervous associations formed with the registration of every mental event, then we can readily imagine that in the senile cases there is merely failure in the establish- ment of new nexuses. Clinicall}^, we have to note that senile subjects fail to register the most ordinary events occurring in their immediate presence. Andriezen has shown that, 'pari passii with the growth and perfection of movement, there is a parallel growth of proto- plasmic processes and collaterals of the nerve-cells in the Rolandic cortex ; and he has urged that the same qualitative elaboration of the structure of the special sense-areas is the organic basis for the facts of psycho-genesis. " Quality (i.e., extent and complexity) of cerebral organisation is the real basis of intellectual capacity, and thus a brain small in size (like that of Gambetta) may, from its high intrinsic elaboration, be able to subserve more varied, extensive, and multiform activities in life 360 DISOEDERS OF MEMOEY. and thought than others of greater size bnt grosser organisa- tion can."* It is difficult to understand how the quantitative elaboration of phj^sical structures determines the qualitj^ of the intellect. A man who looks at a Punch and Judy show possesses at the time an amount of psychical activity, which quantitatively might compare favourably with that of an astronomer when he beholds a comet. Moreover, an illiterate gossamer may retain the memory of concrete facts (by his method of elaborating associations) far better than a philosopher who deals entireh' with abstract thought and its elaborations. Therefore, if memory is to be determined quantitatively in this way, we raise difficulties which are insurmountable. We cannot reconcile the qualitative 2^^i&'^'>'0inena of mind with the (picmtitative phenomena of matter. Were the intellectual capacity dependent upon the number of ramifications, and these in turn dependent upon the number of psychical activities, of which they are regarded as the physical counterpart, then it would be reasonable to assume that intellect is merely a quantitative phenomenon. Otherwise, we must raise an hypothesis that ordinary perceptions and associative ideas do not rest upon such greatly elaborated physical processes as do those mental acts which are classed as scientific or philosophical. That is to say, if we wish the physical explanation to be complete, we must give a clear proof that thoughts of a logical, scientific, or philosophical order have more ramifications than thoughts of an ordinar}' psychological nature. In a psychical sense, the brain of the illiterate person is as active as that of the philosopher. It is not a question of quantity. We are unable to grasp the meaning of mental qualities from a physiological point of view. From a psj^cho- logical point of view we can understand how the mind may regulate and select, as it were, the nature of its retentions ; but that intellectual operations, or the ways Ave ought to think, possess any structural advantages over the ordinary psychical activities, or ways we do think, is a question which we have not been able to determine. As yet, however, our knowledge of the anatomy and dynamical relations of the nerve-cells and their processes, is so meagre, and so incompletely representative of * " Journ. Ment. Science," Oct., 1894, p. 678. PARTIAL AMNESIAS. 361 the complex, yet clear succession of mental operations, that the subject can only be left for future consideration. Partial Amnesias. — It is commonly assumed that every recollection has its seat in a definite and determinate portion of the cerebral hemispheres. Each portion has its special function to perform, but is in intimate relation with its fellows. Ribot compares each particular form of memory with a contingent of clerks charged with a special and exclusive service. Any one of these departments might be abolished without serious detri- ment to the rest of the work, and that is what happens in partial disorders of the memory. It seems unnecessar}^ to dwell upon the fact, that no one is equally perfect in all departments of his memoiy. Some are unable to recall names, places, or events ; others are deficient in their memory for tones or colours. Sometimes this deficiency is fully recognised by the individual, and the local memory for one series of events is habitually associated with that of another series in order to facilitate the process of recall. The forms of partial amnesia may be divided into two groups — viz. : (1) Those forms in which there is loss of memory of a series of mental states, without any obvious interference with the activities of the mind as a whole; (2) those forms in which the loss is due to disease or injury of certain nei've-elements. In the former group there may be temporary suspension of some of the mental functions ; whilst, in the latter, there is destruction of some of them. In a work of this description it would be out of place to consider fully all the cjuestions involved in disorders of intellec- tual expression by speech and writing as met with in aphemia, agraphia, aphasia, amnesia, etc. We must, however, consider, together with those conditions in which there is aphasic loss or impairment in the power of speaking, with amnesic defects in ^\■riting, the cases in which there is aphasic loss of power of writing, with amnesic defects in speaking ; and also the cases in which there are amnesic defects only in speech or writing, or in both. In amnesic patients, generally, there is difficulty in finding the right words, or wrong words are substituted. There is seldom any difficulty in repeating a word after it has been pronounced by some other person, showing that there is no difficulty in articulation. 362 DISORDERS OF MEMORY. From the point of view of localisation, amnesic defects of speech present great difficulties. We have many data which help lis in localising aphasic conditions, whereas fviller informa- tion is required for the localisation of different amnesic defects.* Bastianf believes that lesions about the posterior extremity of the Sylvian fissure of the left hemisphere probably cause one or other variety of amnesia, as lesions of or about the third left frontal cause aphasia. The former region includes the angular gyrus, the supra-marginal lobule, and the posterior half of the upper temporal convolution. * Bastian has formulated the following comprehensive scheme for the study of speech defects : — Scheme for the Kvaminatioii of Aphasic and Amnesic Persons. Auditory Perceptive Centre, with its afferent and efferent fibres — 1. Hearing — good or bad? ^ m ^ ^ ^i ^ ^- i ^- -^ „ ,, , • r 1 To test the functional activity 2. Comprehension or speech. L ^ «, . ^, i * *u ^ . . ,. r. , • i of afferent hbres and oi the 3. Appreciation or vocal music. ^ -^ ir ^^ . ^ ^ , • J centre itselt. „ „ instrumental music ^ ({a) Imitative. \ {/>) Associational (repeti- L^ ^^^^ ^j^^ functional activity , r, 1 / tion 01 numerals, \ . ^, . . c ■.. te 4. Speech < , , , ^ . r > ot the centre and ot its ener- '- ^ alphabet, days or / „. week, etc.). I (c) Spontaneous. / Visual Perceptive Centre, with its afferent and efferent fibres — 1. Sight — good or bad? >y 2. Comprehension of printed or written words. 3. Recognition of numerals or letters To test the functional activity (as judged by ability to point > of afferent fibres and of the them out). centre itself. 4. Recognition of common objects. 5. Recognition of pictures of common objects. f(a) Imitative (copying of \ numerals or letters, j or "transfer copy- [To test the functional activity 6. Writing/ ing" of letters or? of the centre and of ils efter- words). V ent fibres. (/)) Associational. i (c) Spontaneous. ' Commissures between the auditory and the visual centres (visuo-auditory and audito-visual) — C Naming at sight common objects, numerals, letters, or words. ■ \ Reading aloud. 2. Writing from dictation, numerals, letters, words, or propositions. t "Brain as an Organ of Mind," p. 682. PARTIAL AMNESIAS. 363 This view is supported on clinical and pathological grounds, and also from the fact that the posterior third of the hinder segment of the internal capsule conveys all the sensory im- pressions both general and special from one half of the body, and also because the fibres composing this posterior third of the hinder segment of the internal capsule (which lies between the posterior extremity of the lenticular nucleus and the posterior half of the thalamus) begin to be distributed to the convolutions in parts contiguous to the posterior extremity of the Sylvian fissure. Of possible faults in the vocal and oi-al mechanisms we shall speak later, when we discuss motor aphasias. For the present we have to recognise that language is the instrument of thought. " It is," says Wyllie,* "the magic mirror in which a man may look and read the thoughts of another person, or into which he may cast his own thoughts for another's information. It was by the mind's own efforts that the mirror was originally polished and made efficient ; and it is only by the mind's constant attention that it can be kept in good order for daily use. When the mind is damaged, the mirror truthfully reflects a damaged and distorted image. When the mirror is damaged, the reflected images of the mind is not a good and true one ; it is blurred, if not distorted, owing to fault in the reflecting power of the mirror." We have already discussed the question as to the revival of sense-images or memories that are supposed to have been stored up in the cortical centres belonging to the various senses. Each organ of sense must have its cortical area somewhere in the brain, and each centre must not only be instrumental in the reception of fresh impressions, but must also be the storehouse of former presentations and their asso- ciations. These storehouses must accommodate the material counterparts of sensations derived through the special senses and the kinesthetic sense. As to whether the revived images are perceived in some supreme ideational centre, or whether they are perceived in what we regard as their own areas, we have alread}^ expressed an opinion. We have hitherto been unable to find a supreme ideational centre, and this itself leads * "The Disorders of Speech," p. 183 364 DISORDERS OF MEMORY. ITS to favour the latter view. With our advance in knowlede-e of cerebral localisation we shall probably be able to settle this question more definitely. In the meantime, however, we repeat, that we do not know the minute anatomical relations between the storehouses of revivable images and the organs of perception. Aphasia in one or other of its forms may be produced by affections of the ingoing or outgoing channels or centres, or of the commissural fibres between them. According to Wernicke, motor aphasia occurs if the motor centre is affected, and sensory aphasia if the sensory. Clinically, the following forms are those which are more commonly met with : — * 1. Ataxic aphasia (Kussmaul), in which there is loss of volitional speech, repetition of words, reading aloud, volitional writing, and writing to dictation. The patient, however, is able to understand spoken language, written language, and possesses the faculty of copying. The lesion is at the centre for motor images. 2. Sensorial aphasia (Wernicke), in which there is loss of understanding of spoken and written language, inability to repeat words, to write to dictation, and to read aloud. The patient can write or copy words. Volitional speech is im- perfect, and paraphasia may exist. The lesion is at the centre for aiiditory images. 3. Commissural aplutsia (Wernicke) may occur as the result of lesions affecting the various commissural fibres. The chief forms are : — (a) Lesions bet^^■een the perception centre and the centre for motor images cause motor aphasia with loss of volitional speech and volitional writing, but the patient understands spoken and written language, and can cop3^ This variety differs from Broca's aphasia, in that the patient can repeat words, write to dictation, and read aloud. (/;) Lesions between the centre for motor images and speech apparatus cause Broca's aphasia, but the patient can write at will and to dictation. In some cases the thoughts can be ex- pressed in writing, although the patient is unable to speak. * Landois and Stirling, p. 712. PARTIAL AMNESIAS. 365 (c) Lesions between the centre for auditory images and the perception centre cause loss of understanding of spoken and written language ; but there is volitional speech (paraphasia), volitional writing (paragraphia), the power of repeating words, of reading aloud, of writing to dictation, and of copying words. The patient, however, does not understand what he repeats, reads aloud, or copies. In amnesic aphasia, should the patient hear a word, he is able to appreciate its full significance. Occasionally, only certain words are forgotten, or only parts of words are spoken. Kussmaul employs the term paraphasia for that condition in which there is inability to connect rightly the ideas with the proper words to express those ideas, so that, instead of giving expression to the proper ideas, the sense may be perverted, or the form of words may be unintelligible. AgrammaMson and aiaxaphasiaj are terms used to indicate the inability to form the words grammatically and to arrange them synthetically into sentences. Other conditions due to derangement of the cortex are described as hradijphasia, a pathological slow way of speaking ; and tumuUus sermonis, a pathological and stuttering way of reading. The motor tract for speech passes along the upper edge of the Island of Reil, then into the substance of the hemispheres internal to the posterior edge of the knee of the internal capsule; thence it passes through the crusta of the left cerebral peduncle into the left half of the pons, where it crosses, then into the medulla oblongata. Total aphasia would result from total destruction of these paths ; whilst oMayihria (defect of articiilation) would result from their partial destruction. Word-blindness and word-deafness may occur alone or in conjunction with each other. A word-blind or word-deaf person is thought to resemble one who in early youth has learned a foreign tongue which he has completely forgotten at a later period. Words and ■s\^ritten characters are heard or read, but the significance of the signs is lost. Wernicke found softening of the first temporo-sphenoidal convolution in all cases of word-deafness. Physical blindness is said to occur after injury or from disease of the lower parietal lobe. Before we can fully understand the physical nature of 366 DISORDERS OF MEMORY. language relations we must know more about the anatomical regions directly concerned with the perceptions derived through the so-called word-seeing, word-hearing, speech, and writing centres. This is the direction in which a certain amount of success is possible. As yet, however, the clinico-pathological evidences have thrown but little light iipon those forms of amnesia which, psychologically considered, are impairments o± the intellectual power. Among the insane, one meets with nearly every variety of aphasia, ataxic and amnesic. Mental confusion, emotional states, transitory conditions of excitement, or even simple nervousness may produce paraphasia, agrammatism, or ataxa- phasia. Bradyphasia, or tumultus sermonis, may occur as temporary conditions during some forms of mental disorder, or they ma}^ be symptomatic of cortical degeneration. Other conditions, such as verbigeration, stuttering, and stammering Avill be considered later. In general paralysis it is not un- common to find that the patient has had in the early stages of the disease slight attacks of partial amnesia. Such attacks may consist in loss of memory for a class of events derived through the medium of any of the special senses ; or there iv.&j be a temporary inability to recall special events. In states of nervous exhaustion or excessive fatigue an individual may fail to recall events or facts in a certain direction. Sometimes the mere volitional activity or concentration of effort involved in an attempt to recall a special event results in an intensification of that partial amnesia. Such an experience is known to everyone, and in not a few instances has this factor, excessive voluntary effort to recall, been the main cause of the amnesia. Hypermnesic States. — The various states of exaltation of memory are of extreme interest psychological!}*, but up to the present time phj^siology has thrown little or no light upon their nature. Exaltations of memory may be general or partial. Sometimes the condition appears to be dependent upon physio- logical causes, such as increased rapidity of the cerebral circulation. More commonly, however, the cause appears to be pathological. Ribot has pointed out, that general excitaiion of the memory frequently appears in acute fevers, that it is still more common in maniacal excitement, in ecstasy, and in HYPERMNESIC STATES. 367 hypnotism, and that sometimes it appears in hysteria and in the early stages of certain diseases of the brain. Hypermnesic conditions are usually transitory. Some cases have been described in which there has been permanent improvement of the memory after an acute fever or injury. Temporary exalta- tions not uncommonly arise in the early stages of acute psychoses. Thus, in general paralysis of the insane a tempo- rary hypermnesia may precede a progressive amnesia, just as a hyperassthesia may precede an anaesthesia. Various toxic deliriums are attended with hypermnesia. Poisoning by alcohol, lead, morphia, absinthe, ether, chloroform, chloral, haschisch, or cocaine, may present initial symptoms of exalta- tion, which precede the more grave mental disturbances. The innumerable instances of partial hypermnesia have usually been associated with morbid mental states or with defects in the other mental faculties. Of the extraordinary examples of revivification of long forgotten facts, and of the various hypotheses which have been advanced to explain them, we could say much ; but we refrain, inasmuch as the boundaries of our positive knowledge with regard to them are so limited. In idiots, imbeciles, and geniuses, we find examples of excessive retentiveness of memory in certain limited directions. Forbes Winslow* quotes a case of a man who could remember the day when every person had been buried in the parish for thirty-five years, and could repeat with unvarying accuracy the name and age of the deceased, and the mourners at the funeral. " But he was a complete fool. Out of the line of burials he had not one idea, could not give an intelligible reply to a single question, nor be trusted even to feed himself." A boy at the Royal Albert Asylum remembered accurately the name, date of entrance, and the amount of clothing of every patient admitted to the institution for manj^ years. In other respects he was an idiot. Another patient, at the Earlswood Asylum, could give an account of historical facts and dates with extreme facility. On being questioned upon any historical subject, he showed evidence of being the possessor of a memory which was almost encyclopEedic. In the Massa- chusetts Asylum, for the blind, a female deaf and blind mute * " Obscure Diseases of the Brain and Mind," 1863, p. 586. 368 DISORDERS OF MEMORY. possessed an extraordinarily keen sense ot smell. An3-body A\hom she had met liefore, she recognised b}' smell. She knew all her acquaintances by the smell of their hands. In sorting- clothes that had come for the wash, she could distinguish those of each friend. If half a dozen strano-ers threw each his R'love into a hat, and the gloves were mixed, she would take them up. and by means of smell alone assign them to their owners. Maudsley records the case of an idiot who could repeat accurately a page or more of any book which he had read years before, even though it was a book Avhicli he did not understand in the least. The proverbial memory of Macaulay, and that of Ben Jonson, who could repeat all that they had ever "written, and whole books that they had read, are instances in which the memory itself was one of the essential elements of their genius. Niebuhr, Gibbon, Pascal, Leibnitz, Burke, Themistocles, and Cyrus, also possessed extraordinary memories. It is difficult to imagine the physiological " process of association" which determines such phenomenal conditions. In these instances there is no constant repetition of the process of association which makes the connection easier. Bain believes, that in the nerve-cells, where the currents meet and join, there is, in consequence of the meeting. a strengthened connection or diminished obstruction ; a prefer- ence track for that line over other lines where no continuity has been established. How far this hypothesis is ade- Cj[uate we have already inquired, and we do not deem it necessary to revert to the subject. Luys quotes the instance of a young married lady who had listened to one of his lectures, and who could repeat the lecture several months afterwards in a state of somnambulism. When awakened, however, she was utterly unable to repeat a single word of the lectxire. She said she had not listened to it, she had not under- stood a word of it. and could not say a single line. Faramnesia. — The various illusions of memory — where an individual believes that he has before experienced circum- stances which are actually new to him — have been tei*med jDaramnesic states. Kraepelin* has grouped these states in three classes : — * " Archiv. f. Psychiatrie," xvii. and xviii. PARAMNESIA. 369 1. 8imple paramnesia, a simple image which appears as a recollection. These illusions are very common in general paralysis of the insane. Thus, general paralytics will give marvellous accounts of what they have seen and what the}' have clone, although the accounts have no real foundation in fact. In some forms of alcoholic insanity, it is not uncommon for the patient to give details of experiences imagined to have been undergone. One patient, at present in Bethlem, suffering from alcoholic peripheral neuritis, asserts j^ositively that she has been out for a walk in the garden ; whereas, she has been kept constantly in her bed. In some of these cases an illusion or hallucination may have been the initial factor in the production of the paramnesia, inasmuch as the confusion results from inability to distinguish between what was actually a false sensory perception and a perception having a foundation upon an objective reality. When there is revivification of an imagined image, the fact that the primary image was imaginary may be lost sight of, and the present revival appears to be based upon fact. 2. Paramnesia hi/ identification, a new experience appears as the photography of a former one (Kraepelin). Some lunatics, brought for the first time into an asylum, have the feeling as if they had been there before and had seen the same persons on some former occasion. According to Ribot, the illusion is easily explained. " The received impression evokes analogous impressions in the past — vague, confused, and scarcely tangible, — but sufficiently distinct to induce the belief that the new state is a repetition. I'here is a basis of resemblance between the two states of consciousness, which is readily perceived, and which leads to an imaginary identification. It is an error, but only in part, since there is really in the recorded impressions of the past something- resembling a first experience. If this explanation is sufficient for ver}' simple cases, there are others where it is inadmissible." 3. Associated or suggested^ para'tnnesia, " an actual impres- sion suggests an illusion of the memory — a pseudo-recollec- tion of something similar in the past." The explanation of the method by which actual impressions suggest illusions of the memory is at present unsatisfactory. We all experience the 24 ..- 370 DISOEDERS OF MEMOHY. condition of associated or suggested paramnesia, biit it is more noticeable in those who are mentally unstable. Ribot suggests that the image is ver}^ intense and of the nature of a hallucina- tion ; it imposes itself upon the mind as a reality because there is nothing by which the illusion may be rectified. " Hence, the real impression is relegated to a secondary place as a recollection ; it is localised in the past ; wrongly, if the facts are considered in an objective sense ; rightly, if we take the subjective view." Before concluding this part of our subject, mention must be made of those somewhat rare and interesting conditions in which, although a patient may be suffering from dementia with inability to frame one coherent sentence, he yet, nevertheless, retains the power of playing as good a game at whist as ever ; and, moreover, notes and remembers the cards played out. Such instances furnish iis with difficulties which cannot be explained from either a physiological or pathological point of view. Later, we shall endeavour to harmonise some of the pathological conditions of memory with Hughlings-Jackson's scheme of factors of the insanities ; but we shall see that his hypothesis is far from being sufficient to explain manj^ of the variations in memory met with in the insane. Some of our conclusions, then, in regard to memory must be as follows : — (1) We do not yet definitely know its seat in the cortex ; (2) we do not know how mental impressions are fixed and retained ; (3) we do not know how nutrition of the ever- changing brain-substance affects the exactness of the assimila- tion accomplished in the formative process ; (4) we do not know the physiological conditions which cause either instability or fixation of recollections ; (5) we do not understand how disintegration of molecular structures from too rapid com- bustion can determine amnesic states which can be recovered from (in such instances the memory is often completely regained) ; (6) the physiological explanation of the organisation of memory is incomprehensible ; (7) we can conceive the variations and laws of memory only in their psj^chical aspects ; (8) we believe that there must be some substantial counterpart of memory, but we are unable to understand its nature. The hypotheses that have been advanced to account for the new PARAMNESIA. 371 state, the organic registration, and the process of organisation, do not in reality prove adequate ; and, lastly, (9) in the future our knowledge of the relations of various areas and tracts may help in the elucidation of the active processes of recall ; but that ^^•e shall ever be able fully to explain the phenomenon of memory as a subjective state we do not deem possible. The belief that feelings, ideas, and intellectual actions in general, are not fixed, and only become a portion of memory when there are corresponding residua in the nervous system, has gained ground considerably. Further, it is generally held, that on these conditions, and these onh', can there be conservation and reproduction. We have already devoted a considerable amount of attention to the possibilities of the truth of such doctrines, and we are compelled to remain in a condition of uncertainty, because we are unable to form any conception as to what does take place. We do not wish to falsify existing truths, and thereby block the way to further knowledge ; we merely wish to point out, that the doctrines which have been propounded ai'e not in themselves adequate to meet the requirements of the mind. In speculative physiology, little or no account is taken of the nature and laws of mind, and whilst, on the one hand, speculative psychology errs because it tends to ignore the infinite and varied functions of the brain, so, on the other hand, speculative physiology errs because it fails to appreciate the infinite varieties of phenomena that exist in the mind that perceives, thinks, imagines, remembers, feels, and wills. Lord Salisbury did well when he took a survey, not of our science, but of our ignorance. He pointed out, that we are living in a small bright oasis of knowledge, surrounded on all sides by a vast unexplored region of impenetrable mystery. Among the scientific enigmas which still, at the end of the nineteenth century, defy solution, he included the nature and origin of what are called the elements, the action of an unknown force on ordinary matter, as manifested in animal and vegetable life. To these Ave may add, the physiological activities which are regarded as being the counterparts of mind. Criticising Weismann's statement, " We accept natural selection because we must, because it is the only possible explanation that we 372 DISORDERS OF MEMORY. can conceive," he said that, as a politician, he (Lord Salisbury) knew that argument very well. ' In political controversy it was sometimes said of a disputed proposal that it " holds the field," that it must be accepted because no possible alternative had been suggested. In politics there was occasionally a certain validity in the argument, for it sometimes happened that a definite course must be taken, even though no course was free from objection. But such a line of reasoning was utterly out of place in science. We were under no obligation to find a theory if the facts would not jDrovide a sound one.' In these striking observations we find a complete shelter for all we have said about the fanciful hypotheses in the domain of physiology. The onh^ difference between our position and that of Professor Weismann rests in the fact, that whereas he believes that we are able to demonstrate the processes of natural selection in detail, and can with more or less ease imagine them, we are totally unable to demonstrate any psycho-physical pro- cesses in detail. Further, when we try to imagine, or speculate upon, the transcendental aspects of these questions, our efforts prove unsatisfactory, and we are forced to rest content with that which is empirical and within the realms of human reason. 373 CHAPTER XII. Feelings. States of Feeling — Relation of Feeling to Knowing^Instincts and Emotions — Theory of the Emotions — Temperaments — Laws of Pleasure and Pain— Tone of Feeling — Physiological Theory of the Feelings — Feeling of Effort — Varieties of Feelings — Classifi- cations. DlSOEDEfiS OF THE FeELIXGS AND EilOTIONS. Sense Feelings — Feelings Connected with Ideas — Intellectual Feehngs — Rational Feelings — Disorders of Childhood, Puberty, Ado- lescence. FEELIXGS. Any state of consciousness which is pleasurable or painful is known as a state of feeling, and it is upheld by many, that every state of feeling has a pleasurable or painful aspect in some degree. Bain speaks of a neutral excitement ; but, as Volkmann observes, it is difficult to understand how any feeling as such can be altogether uncoloured. Feelings have their objective, as well as their subjective, significance. They form the interesting side of life. Thus, they accompany the activities involved in intellectual operations, and furnish the mind with desires and motives for the exercise of volition. The absence or excess of feeling has much to do with the development of mind as a whole. The moral character, the intellectual character, and the active side of mental life, are intimatelj" dependent upon its presence. When we study the human mind, we see, not only a combination of intellect, feeling, and will, but also, in a manner, we recognise objectively by observation, or subjectively 374 FEELINGS. . by introspection, a varying inequality or preponderance of one or other of these psychic manifestations according to circum- stances. It is rare to meet with pei'fect equalitj^ or equanimity ; and, moreover, the preponderance of one psychic manifestation is commonly regarded as implying a decrease or impairment of one or other psychic state. The relation of feeling to knowing has been clearly pointed out by Sully. It is impossible to carry out intellectual operations effectively, if, at the same moment, there is any strong emotional feeling. '• All violent feeling takes possession of the mind, masters the attention, and precludes the due carrying out of the intellectual process." Thus, the emotional tempera- ment is extremely difficult to train intellectually. On the other hand, a certain amount of interest or feeling is absolutely necessary for intellectual growth. As associated with higher feelings, or with complex sentiments, a certain degree of abstract thought is necessary. Hence, we see that the intellect and the emotions are to a certain extent essential to each other. The older psychologists held, that feeling and intellection were neces- sarily antagonistic to each other. Volkmann* argues, that there is a close connection between feeling and intellectual activity. Spencer upholds the view, that our feelings are to a large extent made up of confused representations of ancestral experiences. HorAviczf regards feeling as the primordial type of mental manifestation. Schneider, ^ on the other hand, believes, that in the simplest sensational consciousness there is involved a rudi- ment of intellection in the shape of the discrimination of a state as favourable or unfavourable. Ward, Wundt, Shopenhauer, and others appear to think that activity, impulse, or volition is the fundamental psychological phenomenon. Some writers regard intellection as being essentially a reflex phenomenon, the excitation consisting in a presentative or representative stimulus. Feeling, as the invariable accom- paniment of intellection, may, in a certain sense, be regarded as a reflex also ; whilst volition, being the result of j)revious • " Lehrbuch der Psychologie," vol. ii. sects. 127 and 129. t "Psycli. Anal.," Theil. i., Abschn vi., and Theil ii., Halfte. t " Der Menschliche Wille," cap. ix. p. 190 et seq. ; and AV'ard, " Mind," vol. viii. 1883, p. 472. INSTINCTS AND EMOTIONS. 375 acquisitions, intellectual or emotional, appears to be even more a reflex activity. AVe must assume that all intellectual, emotional, and volitional activities are .intimately connected in mentalisation. Some urge that the two former (in their elementary states) are coincidental conditions, whilst the latter is a result. From another point of view, intellection is regarded as the outcome of volition or emotion. It is difficult to dx'aw a definite line between instincts and emotions. Their relation is very intimate, and conditions which excite the one, as a rule excite the other. According to James, emotions fall short of instincts, in that the emotional reaction usually terminates in the subject's own body, whilst the in- stinctive reaction is apt to go farther and enter into practical relations with the exciting object. He also gives the theory, that bodily changes follow directly the perception of the exciting fact, and. that our feeling of the same changes as they occur is tJie emotion. Further, " every one of the bodily changes, whatsoever it be, is felt, acutely or obscurely, the moment it occurs. . . If we fancy some strong emotion, and then try to abstract from our consciousness of it all the feelings of its bodily symptoms, we find we have nothing left behind. . . . for us, emotion dissociated from, all bodily feeling is inconceivable. ... If such a theory is true, then each emotion is the resultant of a sum of elements, and each element is caused by a physiological process of a sort alreadj^ well known. The elements are all organic changes, and each of them is the reflex effect of the exciting object. The moment the genesis of an emotion is accounted for, as the arousal by an object of a lot of reflex acts which are forthwith felt, we immediately see why there is no limit to the number of possible different emotions which may exist, and why the emotions of different individuals may vary indefinitely, both as to their constitution and as to objects which call them forth. . . . Any classification of the emotions is seen to be as true and as ' natural ' as any other, if it only serves some purpose." It is difficult to reconcile ourselves to this theory, and we feel that there are many instances which cannot he accounted for in this way. Thus, in various dream-states, it is hard to imagine that an intense emotional state is the result of any 376 FEELINGS. reflex effect of an exciting object. In our ordinary waking moments we may experience various emotional states without the slightest reference to any physical impressions : there may be none of those wide-spread bodily effects antecedent to the arousal of an emotion or emotional idea. We are all aware, that extremely rapid reflex acts may occur through immediate psychical influences, and that we subsequently experience the effects of those acts ; but the rapidity of those immediate psychical influences does not warrant that we should lose sight of them altogether, and only take into account the reflex acts themselves. The best proof that the immediate cause of emotion is a physical effect on the nerves, is, according to James, furnished by those pathological cases in which the emotion is objectless. " It must be confessed, that there are cases of morbid fear in which objectively the heart is not much per- turbed. These, however, fail to prove anything against our theory, for it is of course possible that the cortical centres normally percipient of dread as a complex of cardiac and other organic sensations due to real bodily change, should become primarily excited in brain-disease, and give rise to an hallucina- tion of the changes being there — an hallucination of dread, consequently co-existent with a comparatively calm piilse, etc. I say it is possible, for I am ignorant of observations Mhich might test the fact. Trance, ecstasy, etc., offer analogous examples, not to speak of ordinary dreaming. Under all these conditions, one might have the liveliest subjective feelings either of eye or ear, or of the more visceral and emotional sort, as a result of pure nerve-central activity ; and yet, as I believe, with complete peripheral repose." * Professor Lange, of Copenhagen, published, in 1884, a theory almost identical with that of Professor James. He considered the emotion to be the effect of the organic changes, muscular and visceral, of which the expression of the emotion consisted. The order of events was regarded to be as follows : — (1) An immediate reflex follo\\'ing upon the presence of the object, the organic change in question being regarded as the primar}^ effect; (2) a secondary feeling indirectly aroused. * '• Psychology,"' vol. ii. p. 459. THEORY OF THE EMOTIONS. 377 Wiindt* has severely criticised this view, and has pointed out that the same vaso-motor factors may be attended by totally different emotions — ejf., joy and anger. Moreover, if a certain stimulus causes emotional expression by its mere reflex effects, why is it that another stimulus, almost identical with the first, will fail to do so if its mental effects are not the same ? f The question would appear to be, Does the emotional excitement which follows the idea follow it immediately, or secondarily, and as a consequence of the diffusive " wave " of impulses around ? % If the diffusive wave of impulses causes the emotion, there ought to be some constant relation between the nature of the wave and the character of the emotion. The origin of an emotion would appear to be as follows : — (1) The objective qualities with which perception acquaints us affect us with pleasure or displeasure — i.e., the perceptions are accom- panied by a tone of feeling. (2) There may, or may not be, a physical reaction to the idea of the qualities of the object ; this would determine the origin of the secondary sensations, which would constitute the emotion. Professor James merely advocates that such organic sensations being also presumably due to incoming currents, the result is that the whole of consciousness seems to be outwardly mediated by these. In * " Philosopliische Studien," vi., 1891, p. 349. t It is difficult to imagine how an object rier se can determine the physi- cal effects apart from the subjective feeling towards the object. Irons ("Mind," p. 78, 1894) says, "If I were not afraid, the object would not be an object of teiTor."' Worcester ("The Monist," 1893, vol. iii. p. 285) says, " Neither running nor any other of the symptoms of fear which he (Professor James) enumerates is the necessary result of seeing a bear. A chained or caged bear may excite only feelings of curiosity, and a well-armed hunter might experience only pleasurable feelings at meeting one loose in the woods. It is not, then, the perception of the bear that excites the movement of fear. We do not run from the bear unless we suppose him capable of doing us bodily injury. AV'hy should the expecta- tion of being eaten, for instance, set the muscles of our legs in motion ? Common sense would be likely to say that it was because we object to being eaten ; but, according to Professor James, the reason we dislike to be eaten is because we run away." In reply to the latter criticism, Professor James somewhat modifies his position, and agrees that the same bear may tridy enough excite us either to tight or flight, according as he suggests an over- powering ■' idea "' of his killing us, or of our killing him. + " Psychological Review," vol. i. No. 5, p. 518. 378 FEELINGS. short, this theory of the emotions applies only to the rani- feelings of excitement vhich are more especially derived from orgoMic visceral reflex states. The observations of Sollier* seem to confirm the view, that the rank emotions depend ahnost exclusively on visceral sensations. We now turn to some other considerations which have engaged the attention of psychologists and mental physiologists. For an emotional type of character a lively imagination is a prerequisite. Unless the imagination is in full force, the life will be almost emotionless. Emotions are only slightly re- vivable in memory, and by repetition they tend to become more and more blunted. Here it may be well to speak of those psycho-physical differences between men which are designated as temperaments. When we consider the four temperaments described by the ancients, we find that pathological conditions of the mind can be assigned to them with a certain amount of appropriateness. In general, the ancients found either a predominant spontaneity or a predominant receptivity. The former gave the active, the latter the passive, temperament, whilst, from the greater or less permanei^cy of actions or impressions, they devised a fourfold subdivision. These four temperaments were : — (1) The sanguine or passive, with receptivity easily, but not deeply, affected ; (2) the melancholy, with receptivity capable of being deepl}^ affected; (3) the choleric or active, with quick, vigorous, but not durable, activity ; and (4) the phlegmatic, with slow but enduring activity.! The Lairs of Pleasure and. Pain. — It is almost universal!}' held that some form of nervous activity is involved in ever}^ variety of pleasure and pain. Some writers refer only to the mental activities involved ; others deal almost exclusively with the nervous accompaniments or activities of organs which either directly or indirectly affect the nerve-centres. Leibnitz regards the cognition of furthered vitality as the mode of mental activity which gives rise to feelings of pleasure. We may take it, that all sensations or feelings of pleasure involve a certain * " Reclierches sur les Rapports de la Sensibilite et de rEmotion," — "Revue Pliilosophique,"' March, 1894, vol. xxxvii. p. 241. t Kant,"Anthrop.," p. 273 ; Fevichtersleben, " Medical Psychology," p. 144. LAWS OF PLEASURE AND PAIN. 379 amount of mental- activity and a reference to some physical state. The tone of feeling accompanies our sensations with varj'ing degrees of intensity. Ziehen makes a sharp distinction between the tone of feeling which accompanies the sensation as such, and the tone of feeling that accompanies the ideas or images of memory, whose activity has no direct reference to the sensations. Sensations do not in themselves alone determine the various emotional feelings. The mental accompaniments of the various sensations usually derive their emotional tone from ideas and former acquisitions. The emotional tone of a sensation is, to a certain extent, dependent upon the intensity of the sensation in consciousness. The relation of the strength of the stimulus to the degree of feeling has been formulated by Wundt,* who found that as soon as the stimulus passes the threshold and causes an appre- ciable sensation it begins to be pleasurable, and the pleasure goes on increasing as the stimulus is increased. At length a point or region of maximum pleasure is reached, which probably answers to that medium region of the scale where the finest discrimination is possible. From this point the pleasure rapidly diminishes till a certain point of indifference is readied. Above this, any further increase produces pain, which in its turn increases until it culminates as the maximum of pain is reached. This law is exemplified in all the higher senses. Horwiczf and Beneke have pointed out, that feelings of pain are some- times associated with very weak sensations.:): Wundt believes, that in this case the indifference-point is so low that it is no longer distinguishable from the threshold. In morbid states, such as melancholia, the law does not hold good. It is held that melancholic patients have usually painful feelings with every degree of sensation. It is a common observation, how- ever, that with morbid mental depression there is often failure to respond normally to ordinary depressing causes, and we may formulate the general law, that iiitlt, the deptJi or degree of patho- * " Physiol. Psychologie," chap. x. sect. i. t " Psychol. Analysen," s. ii. 2, 26. X Ziehen, op. cit.. p. 132. Cesca, " Die Lehre von der Natur der Gef iihle." Vierteljschr. f iir wiss. Phil., 1886, x. Compare also Kiilpe, " Zur Theorie der Sinnlichen Gefiihle." 380 FEELINGS. logical melancholia there is an inverse degree of normal reaction to painful sensations or suggestions. For example, the reception of bad news has little or no emotional effect upon those who are already morbidly depressed. It is generally held, that a feeling of pain accompanies the slightest sensation, and that in con- ditions of melancholia there is painful response to mnch slighter intensities of sensation than in conditions of health. We hold that the opposite is true. Every sensation is received and coloured by a mind saturated with melancholic ideas, but the addition of such percepts, coloured though they may become, does not intensifj^ the condition of depression. On the con- trary, just as the addition of a clear fluid to a coloured one will tend to weaken the depth of that colour, so the addition of ordinary perceptions tends to dilute the condition of grief or pain in the melancholiac. Undoubtedly, sensations do become realised in consciousness as painful states, but with every realisation or reaction to normal influences, the morbid thought tends to become diluted, as it were, until, with the process of recovery, the individual responds normally to all stimuli from without. The law simply amounts to the fact, that with the rise of subject consciousness there is a corresponding diminution of object-consciousness — i.e., the attention becomes absorbed by subjective sensations. The tone of feeling which accompanies the various sensa- tions is dependent, therefore, only to a certain extent upon the intensity of the sensation. Of the qualities of sensations as factors in the production of tones of feeling, we have little to add to what has already been said. The tone of feelings may be taken as dependent upon the intensity and qiiality of sensations, plus associated ideas. Fechner* has called attention to the spatial arrangement of sensations as a factor in the determination of positive tones of feeling. The time-relationships of sensations, and their accom- panying tone of feeling, have been clearly demonstrated by Ziehen. He points out, that we project our sensations into a space of three dimensions, while not only our sensations, but also their mental images (the ideas) are arranged with reference to time in but one direction. * " Vorschule der ^Esthetik." Tli. i., Absclm xiv. LAWS OF PLEASURE AND PAIN. 381 To explain how the tone of feeling- accompanying sensations is dependent on their duration and succession in time, Ziehen says : — " A long duration of sensation generally dampens both positive and negative tones of feeling. The manner in which several sensations follow one another in time only has an essential influence on the tone of feeling accompanying sensations of musical sound. A series of like sensations of tone, following one after the other, generally becomes wearisome ; even when the quality of the tone changes an unpleasant feeling soon appears. " In order to obtain the pleasurable feeling belonging to rhythmical division, either the intensity or the duration of the single tones must be subjected to a more or less regular periodic change. In musical tempo, and the versification of poetry, we have sequences of acoustic- sensations, in which certain sensations are especially accented or intense, and all together have a definite duration. The qualities {i.e., the notes and words) change, but the intensities of tone, the accentuations and diminutions, constantly recur at definite intervals or periodically. In poetry, the close of such rhythmical periods can often be emphatically marked by choosing very similar tones with which to close the periods. In this form of emphasis lies the importance of the rhythm. "As regards the succession of sensations, therefore, a regular periodicity is the chief condition for the appearance of feelings of pleasure. It is not mere chance that maniacs and those afflicted with emotional paranoia often speak in rhythm and rhyme. Such phe- nomena harmonise rather with the morbid, positive emotional states characterising these forms of psychosis." The contention with regard to the "tone of feelino-" is, whether the feeling arises from the actual sensations, or whether the sensations are attended by a tone of feeling- determined, for the most part, by ideas or images of memory. It seems that the latter condition is the more probable, and that the sensations themselves act by suggestion ; the actual feelings being thus determined secondarily by association. Ziehen rightly believes, that only the intensity of the sensations and their succession in time and space have any direct effect upon their tone of feeling ; hence, we may assume that the other qualitative characteristics of sensations derive their emotional tones from other influences which are AA-holly dependent upon psychical factors, apart from the sensations proper. It is impossible here to re-enter into the question of the relationship of external stimuli to the various sensory struc- 382 FEELINGS. tures. We must content ourselves with a few of the particular applications of the relationship. When the stimulus is inap- propriate, painful states of feeling are apt to occur. There must be a certain proportion between the stimuli and the nervous activity. When the nervous structures are strained or abnormally active, or when their activit}^ is impeded or defective, there may be an emotional accompaniment of dis- pleasure ; but, in general, we are more competent to explain the positive or negative variations in the emotional tone from the subjective side than from the consideration of the objective qualities of sensation. The prolongation of any powerful mode of stimulation pro- duces fatigue and the feeling of pain or displeasure. In order that the tone of feeling may continue as pleasurable, it is necessary that there should be limited duration of the stimu- lation, and variety or contrast of the impressions. This law of the dependence of pleasure on change, has been the basis of most of the negative theories. Bain defines those emotions which depend on change of circumstances as " emotions of relativity " — e.g., states of wonder, novelty, liberty, and power. The tone of feeling which accompanies stimula- tion of the bodil}" apparatus, furthers or retards organic processes. Thus, organic processes are promoted by cheer- fulness of mind, or, conversely, healthy organic processes favour cheerfulness. When there is hindrance of activities, through over-taxation of organic processes, painful feelings are apt to arise ; or over-taxation of the mental or emotional faculties leads to defective organic processes. According to Bain, pleasure is connected with an increase, pain with an abatement of the vital functions.* * Spencer says, the pleasurable activity of any organ (e.g., the palate, coincides in general with what is beneficial or life preserving to the organ- ism. He regards pain as the correlative of actions injurious to the organism, whilst pleasure is the correlative of actions conducive to its welfare. He also holds it to be an inevitable deduction from the hypothesis of evolution, that races of sentient creatures could have come into existence under no other conditions. Psychologically, the intrinsic nature of pleasiu-es and pains will ever prove vexed questions. In the meantime, we must agree with Spencer, who believes that while pleasures and pains are partly consti- tuted of those local and conspicuous elements of feeling directly aroused by .special stimuli, they are largely, if not mainly, composed of secondary TONE OF FEELING. 383 Before entering more fully into a consideration of the physiological theory of the feelings, it is important to recognise, that although the feelings primarily depend npon external agents, yet they are totally disparate in kind and degree. From a comparative point of view, we know that organisation in structure has much to do with the transmission of stimuli, and that subjective effects are qualitatively and quantitatively" determined in some unknown way by objective stimuli ; but the nature of these objective agencies are unknown. Spencer regards the peripherally-initiated feelings that arise in internal organs, and the centrally-initiated feelings or emotions, as having, also, their several forms of relativity. " Thus, the truth that subjective consciousness determined as it is, M'holly by sub- jective nature, state, and circumstances, is no measure of objective existence. What we are conscious of as properties of matter are but subjective affections produced by objective agencies that are unknown and unknowable. All the sensa- tions produced in us by environing things, are but symbols of actions out of ourselves, the nature of which we cannot even conceive."* Further, he concludes, as an obvious corollary from physiological truths, that it is inconceivable that any resem- blance exists bet^^'een the subjective effect and that objective cause which arouses it through the intermediation of changes resembling neither. "Not a step can be taken towards the truth, that our states of consciousness are the only things we can know, without postulating an unknown something bevond consciousness. The only thinkable proposition is, that the active antecedent of each primary feeling exists independently of consciousness." Having fully grasped the truth, that the feelings are subjective phenomena, and that they do not corre- spond, or resemble, any interactions or connections between outer agents, the student will be better able to understand that the feelings themselves are for us nothing but symbols of agencies which are beyond, or antecedent to, states of con- sciousness. In order that feelings may be revived, certain fit states of eletcents of feeling aroused indirectly by diffused stimulation of the nervous system. — (" Inductions of Psychology,'' p. 12S.) * " Epitome of Spencer's Synthetic Philosophy,"' by Collins, p. 207, 884 FEELINGS. the organism are essential. Thus, we know from clinico-patho- logical observations, that defects in the circulatory system may abnormally hinder or promote the revivability of feelings. An active circulation and a blood which contains the required materials may favour the revivabilit}'' ; or a defective circulation and poor blood ma^^ effect an increase of revivability, but with a distortion of the relations between feelings. In acute maniacal states the feelings revived, and the consciousness of their relations, are often morbidly increased ; but the quantita- tive increase of the former more commonly acts as a deterrent to the latter, especiallj'" when the latter are of the same nature as the former. Thus far we have seen that the physiological counter- pai't or actual basis of the feelings is at present little deter- mined. We know no special brain-centres which are concerned with the emotions ; nor do we obtain any knowledge from the scientific investigations upon the presentations of sense or the time relations of mental phenomena. * The attempt to give a ph^^siological explanation of the origin and nature of the feelings, has proved unsatisfactory, and, as we have seen, such an attempt is valueless, because the purely mental states or " associative ideas " cannot be eliminated from consideration. The mere consciousness of certain con- ditions of the nervous elements, or the feeling of furtherance or hindrance of activities, does not form any really conceivable basis for the relations between the subjective and objective facts at our disposal. Ladd regards the theory, which makes feeling a derived consciousness dependent upon the relations of the ideas as furthering or checking each other, as unsatis- factory. Nor does he admit that feeling is a secondary or derived form of consciousness. Horwicz,t Lot^ze,^ and Ladd uphold, that feeling is one of the most primitive and unanalysable of mental activities. The latter writer states, that feeling is an original and underived form of consciousness, * Ladd says, that, " On these matters, nothing but the greatest caution is fitted to inspire confidence ; the supreme wisdom is not infrequently a frank confession of ignorance or uncertainty."' + "Psychol. Analysen,'" i. ]). 168f. X " Medecin. Psychologie," p. 235f. TONE OF FEELING. 385 or mode of the operation of conscious mind. "It can neither be defined by, nor deduced from, sensation or ideation." Attention has been given to the question as to whether the same nervous elements which have to do with sensations are also concerned with the accompanying tone of feeling. Lotze* believes that sensation and feeling are due to two forms of processes in the same nervous elements. Shiff and others believe that nervous impulses resulting in pain travel by more or less distinct paths. Both views may be more or less correct, but the difference between the perception of pain physically occasioned, and the tone of feeling accompanying sensations is so great psychologically, that for our purpose the contention is of little value. For the present we must confess that our knowledge of the physical basis of pleasurable or painful feeling is sadly deficient; it remains to be shown, whether a separate apparatus is involved or not. That a separate mechanism of end-organs, conducting nerve-tracts, and central areas exists for the feelings seems improbable, and the supporters of this theory will have to develop a cerebral association scheme for the re- vivability and relativity of the feelings in relation to, and yet distinct fi'om, the ideational scheme. To account for the tone of feeling which accompanies sensations, and which is derived secondarily from associative ideas, physiology is silent ; nor do we deem it probable that this part of the subject can ever be investigated with positive results. The consideration of the affections and the emotions, or pas- sions, involves at least three important particulars.! (1) The characteristic feeling which distinguishes each ; (2) its relation to the train of ideas, and the changes induced in it by the ideas ; (3) the relations to the different bodily organs, and the reflex effect of the changes in these organs upon both the feelings and the ideas. We know that there is a psvchological connection between perceptions and feelings, but ■s'sdien we attempt to establish a phj-sical basis for the union of the two series of facts, we utterly fail and get beyond our depth. " Speaking generally," says Spencer, " feelings and the relations between feelings correspond to nerve-corpuscles and the fibres which connect nerve-corpuscles, or, rather, to the * Op. cit. pp. 245 ff. t Ladd, " Phys. Psych.," p. 316. 386 FEELINGS. molecular changes, of which nerve-corpuscles are the seats, and the molecular changes transmitted through fibres. The psychical relation between two feelings answers to the physical relation between two disturbed portions of grey matter, which are put in such direct or indirect communica- tion that some discharge takes place between them." Mercier regards the physical substratum of feeling as a very different matter. " It is the discharge itself. The discharge at one end of a nerve- path is the physical substratum of one feeling. The discharge at the other end of the nerve-path is the physical substratum of another feeling, and the current from the one position to the other is the phy- sical substratum of a thought. Now the current is fully accounted for by the discharges. A pressure at one position plus or ininus the pres- sure at the other is sufficient (other things being equal) to determine the setting of a current from the one to the other. Here, then, the physical substratum of thought is complete. It needs upon these lines no further elucidation. But with the substratum of feeling it is other- wise. The current along the nerve-fibre cannot set up the discharge in both positions, and may not initiate it in either. Whence, then, comes the one discharge, and whither does the other go ? Proximately, the one may be set up by discharges coming from other positions, and the other may go to set up similar discharges elsewhere, but ultimately these can be but one source and one outfall for every discharge. Traced to its origin, every discharge of grey matter is set up directly, or with more or less remote indirectness, by currents coming into the grey matter from without — by currents set up by the impact of external forces on the surface of the organism. Traced to its destination, every discharge of grey matter, with which the psychologist is directly concerned, expends itself in producing or altering muscular con- traction — in action on the environment, or in modification of such action. And the physical substratum of feeling is a nervous discharge. Hence we are compelled to affirm that every feeling is conditioned, either by action of the environment on the organism, or by action of the organism on the environment ; and this leads us to the expression of which we are in search. If the foregoing account of the physical substratum of feeling and of the relations of feeling to thought both when viewed introspectively, and when viewed as correspondence are correct, then it follows, that while thought is the establishment of a relation, feeling is the occurrence of a state ; and that while thought is the correspondence of a relation in the organism with a relation in the environment, feeling is the correspondence of a state in the organism with an interaction between the organism and its environment."* "Tlie Nervous System and the Mind," p. 265. TONE OF FEELING. 887 This account of the physical basis of the feelings must l)e accepted with reservation. It would appear that feeling is fo be regarded as the symbol of an antecedent organic state, and that this organic state is determined by discharges within the grey matter. Of the nature and direction of these discharges we are left in complete ignorance. The mere terms " current" and " discharge" are held to be sufficiently explicit in themselves to warrant the construction of such a physical formula. Let the student set himself the task of explaining in detail the physical formulge of the so-called " higher feelings " in- volved in the contemplation of such complex reactions of the mind as found in the utilitarianism of Mill, or the intuition- alism of Calderwood. Then let him reduce to terms of discharge and nerve-currents those feelings associated with moral judgments, laws of individual life, and moral relations, conscience, duty or obligation, biological or psychological evolution, or the ethical philosophy of first cause, self-deter- mination, self-realisation, or finite existence. The attempt wiU be made through the medium of the intellectual operations, and it will be discovered that the higher feelings are com- pounded of ideas, and that, therefore, the elementary components of these feelings must be the elementary components of ideas. Then the student will find that he is no better oiF than before, and that he has to resort to his imagination for the other details. We know nothing about the correspondence of inner and outer relations, nor do we know how one series of changes affects the other series. Tone of feeling is a psychological faft. The correspondence of external and organismal j^i'ocesses with that tone of feeling is inexplicable, and the nature of the external and organismal processes is a matter of pure sjoecula- tion. Many of the aesthetic feelings have l)een investigated from a physiological standpoint, and a rational conception of their origin and nature has been sought by the scientific study of the various presentations of sense. Wundt* has demonstrated, however, that many of the aesthetic feelings do not corresjjond to the sense-feelings, nor are they the outcome of mere com- pounding of such feelings. /Esthetic feelings, according to * "Phys. Psycli.," ii. p. 179 f. 388 FEELINGS. Lacld, may be said to arise from the maimer of the combination of 'Sensuous feelings; time and space furnish the framework in AA'hich they are arranged. The feeling of effort associated with the performance of certain acts has been the subject of much controversy of late. AVe have already alluded to the anatomical relations of the so- called muscular sense, so that it only remains for us to discuss some of its central relations. Miiller* regarded the nervous process to be pureh' central, and to consist in an efferent discharge. Bain and Wundt have adopted somewhat similar views. Ferrier and many others, however, believe that the feeling of effort is a complex of afferent sensations. From the observations already made, we are inclined to adopt the latter view, and to believe that the feeling of effort, with, its tone of feeling, is mainl}^ determined by peripherally incited afferent excitations. The further consideration of this subject will be taken up when we discuss the phenomenon of the will. Paulhanf believes that the emotions are due to an inhibition of impiilsive tendencies. James points out, however, that some Ivinds of emotion — namely, uneasiness, annoyance, distress — do occur when definite impulsive tendencies are checked, but that other emotions are themselves primary impulsive tenden- cies of a diffusive sort (involving a multiplicity of phenomena), and just in proportion as more and more of these multiple tendencies are checked, and replaced by some few narrow forms of discharge, does the original emotion tend to disappear.:]: Darwin, Spencer, James, and others regard the phj^sical expressions of the emotions as being weakened revivals of movements which formerly were useful and necessary for the defence and survival of the subject. Another principle, mentioned by Darwin, and emphasised by James, is called " The principle of reacting similarly to analogous-feeling stimuli." The latter Avriter, in summing wp the whole question of the genesis of the emotions, says, '• We see the reason for a few emotional reactions ; for others a possible species of reason may be guessed, but others remain for which no plausil^le * " Physiologie d. Menschen, ii. p. .'<00. f " Les Pliunomenes Affectifs et les Lois de leur Apparition." t Op. cit., p. 477. TONE OF FEELING. 889 reason can even be conceived. These may be reactions which are purely mechanical results of the way in which onr nervous centres are framed — reactions which, although permanent in us now, may be called accidental as far as their origin goes. In fact, in an organism as complex as the nervous system, there ontist be many such reactions, incidental to others, involved for utility's sake, but which would never themselves have been evolved independently, for any utility they might possess. Sea- sickness, the love of music, of the various intoxicants, nay, the entire testhetic life of man. we have already traced to this accidental origin. It would be foolish to suppose that none of the reactions called emotional could have arisen in this quasi- accidental ^^'a}'." That the movements involved in expression often give a clue to the inner mental life, is perfectly true ; but the corre- spondence between phj^siognomical and mental phenomena is variable, and physical expressions may be entirely independent of any prevailing tone of feeling or emotion. Meynert argues, that the movements of expression var}'' with the emotions ; therefore these movements must be either of an aggressive or repulsive character. According to this observer, physiognomical expression is chief!}" a matter of secondary presentations, which are evolved, like dream-presentations, during the condition of partial sleep, and that expression is dependent altogether upon the simultaneous excitation of such secondary presentations as are associated with our emotions or our thoughts. The complicated system of physical expression, comprising facial movement, attitude, gesture, and intonation, has been elaborated chiefly by Bain, to whose labours in this direction the reader is referred for detailed explanations. Space will not permit us to take any further account of the innumerable con- troversies which have arisen in connection with the physical occasions of the emotions. It must suffice, for the present, to* recognise that all the exjjlanations hitherto rendered by the workers in this field have been as general hypotheses of opera- tive potentialities. The accounts of structures and their related dynamical operations, though meagre in the extreme, and the constitution of the physical scheme, expressed in terms of matter and modes of motion, may widen the range of our 390 FEELINGS. imagination ; but we cannot, in the light of the above generali- sations, satisfy ourselves that Ave have in reality made much advance since the time when Aristotle, with his wonderful psychological insight, anticipated the modern empirical school of thought, and promulgated the doctrine that all knowledge was to be traced to sense and association. Varieties of Feelings. — When we attempt to dissociate the rank feelings frt)m all bodil}^ or sentient experiences, we find that we are without material to explain their genesis, and, moreover, the necessary conditions which express their nature are absent also. That is to say, we so habitually refer to the bodily accompaniments or expressions of the feelings when we experience a state of feeling, that the two (the mental state and the bodily expression) cannot be dissociated. The fact that we do not know how our emotions are conditioned by nervous processes, need not stand in the way of our belief, that each emotion is in some way or other the result of a sum of activities or physiological processes. The causal relation of emotions is bej'ond us, and when we enumerate or describe their varieties, we do not imply more than, that certain mental states have certain bodily accompaniments which undoubtedly derive their reflex effects from organic changes peripherally or centrally initiated. When we take into account the infinite number and variety of reflex acts which may occur in the adjustment of our physical organism to its environment, we see that the number of emotions symbolic of that adjustment is without limit. Among the insane, Ave meet with every variety of emotional accom- paniment due to absence, exaltation, or perversion of reflex activity. Lange has pointed out, that some men are dumb, instead of talkative, with joy. Fright sometimes drives the blood into the head of its victim, instead of making him pale. Grief may cause an individual to run restlessly about lamenting instead of sittino- down and becominp* mute. From what we have already said, the student will no doubt agree, that any one classification of the emotions or feelings is as usefvil and as natural as any other, if it only serves some purpose. It may be advisable here, however, to mention briefly some of the methods of classification adopted by various writers. VARIETIES OF FEEJ.INGS. 391 Sully classifies the varieties of feeling into two main divisions, as follo^^'s : — 1. Sense feelinr/s. — (1) Those arising immediately from a process of nerve-stimulation, more particularly the excitation of sensory (incarrjang) nerves ; and (2) those depending on some mode of mental activity. 2, Emotions and their classes (arranged in a series or ascending scale, according to their degree or complexity, or representativeness.). — The order of their development is : (1) The individual or personal emotions (the pleasures of hope, success, reputation, etc. ; (2) the sympathetic feelings (the participation in others' pleasurable and painful experiences, and kindliness or benevolence of disposition generally) ; (3) the sentiments, (a) intellectual, (/>) gesthetic, (c) moral. Herbert Spencer divides the emotions according to the degree of intellectual activity or representativeness involved. 1. Presentative feelings. — Ordinarily called sensations. Those mental states in which, instead of regarding a corporeal impression as of this or that kind, or as located here or there, we contemplate it in itself as pleasure or pain — ejj., in inhaling a perfume. 2. Presentative-7'ep)'esentative feelings. — A sensation, group of sensations, or group of sensations and ideas, arouses a vast aggregation of represented sensations, partly of individual experience, but chiefly deeper than individual experience, and consequently indefinite — e.g., terror. 3. Representative feelings. — Revived sense-feelings. Com- prehending the ideas of the feelings above classed, when they are called up apart from the appropriate external excitements. The feelings so represented may either be simple ones of the kinds first named (as tastes, colours, sounds, etc.), or they may be involved ones of the kinds last named (as poetical fancies, etc.). 4. Be-7-epresentative feelings. — Involving a more complex or abstract form of representation (as the sentiment of property or of justice). More complex sentient states that are less the direct results of external excitements than the indirect or reflex results of them. It is the abstract of many concrete representations, and so is re-representative (imagination). 392 FEELINGS. Spencer classifies feelings from a standpoint mainly sub- jective. Bain objects to Spencer's system, and arranges the feelings with reference to the external circumstances with which they correspond. Viewed subjectively, feelings have been described according as they are founded on distinctions between their qualities. The following are some of the chief methods of classification : — * Appetites, desires, affections (Reid). Subsidiary faculties, and elaborative faculty (Hamilton). Sensual feeling, intellectual feeling (Kant). Harmony, conflict (Herbart). Affections, moods, passions (Wundt). Direct, reflective, and imaginative emotions (Hodgson). Coupland, following in the lines of Spencer, bases his classification on the degree of representativeness of the under- lying cognitive fact. He speaks of feelings which arise in connection with presentations known as " corporeal," those termed representative or associative, and those re-representative states where every vestige of personal reference has been eliminated, and the pleasure attaches to an object of the pure intellect. Mercier, objecting to the classification of Spencer as " too vague to be of any real service," has constructed a scheme which, in our opinion, is of still less practical value, inasmuch as it involves many assumptions which are doubtful ps^^cho- logically. Ladd has severely criticised Mercier's scheme, and rightly condemns its " uncouth " terminology, artificial dis- tinctions, and cross divisions. For students' purposes, however, we give his scheme which is based upon the main classes of interactions between the environment and the organism, viz. : — I. Those which primarily affect the conservation of the organism. II. Those A\'hich primarily affect the perpetuation of the race. III. Those which primarily affect the common welfare. IV. Those which primarily affect the welfare of others. V. Those which are neither conservative nor destructive. VI. Feelings corresponding with relations between inter- actions. * Mercier, "The Nervous System and the Mind," p. 286. DISORDEES OF THE FEELINGS AND EMOTIONS. 393 Before entering upon the question of the morbid emotional states, it is essential that we should better understand the subjective nature of some of the complex feelings, such as S3'mpathy, and the intellectual, aesthetic, and moral sentiments. Si/mjiatJiy involves the noting of objective facts in others, and the comparison of the objective signs, with the like conditions, in ourselves — i.e., s}' mpathy involves the constructive imagina- tion of the feelings of others in ourselves. Thus, it depends upon the quickness of our obsei-vation, the nature and extent of our own feelings, and the imaginativeness we possess. Sympathj^ is further aided by similarity as to temperament, experience, and age between the objects and ourselves. Association, daily concourse, and personal liking also favour it. The intellectual operations and the sentiments associated with them may be impartial or egoistic. The impartial sub- merge their individuality in the contemplation of the object ; the latter exalt their individuality, and tend to render their contemplation of the object imperfect. For illustrations we have only to glance at some of the scientific and philosophical literature of the day. The aesthetic sentiments are associated with presentations derived through the medium of the special senses. Their elements have been regarded as sensuous, perceptual, correla- tive, and associative. The moral sentiments have been divided into those which are concerned with social questions of obligation, and conduct in life. It is impossible here to discuss the question as to the origin of moral sentiments, for Ave cannot enter upon such extensive subjects as those of intuitionalism or utili- tarianism. The controversy as to whether the moral sentiments are the outgrowth of simpler feelings, or whether they are entirely dependent upon the modelling of environmental con- dition, is one which belongs to the domain of the Philosophy of Ethics. DISORDERS OF THE FEELINGS AND EMOTIONS. Changes or disturbances in some part of the organism itself may act as primary factors in determining morbid feelings. 394 DISORDERS OF THE FEELINGS AND EMOTIONS. The organic sense-feelings are usually vague as to their nature and locality ; thus differing from the feelings which arise in connection with stimulation of the special senses. In conditions such as euphoria and its opposite, malaise, the sum of all the organic feelings constitutes their basis. The general feeling of well-being or ill-being has much to do with the dominant tone of feeling or mental tone at any one time. We have already alluded to the temperaments, and we have noted that each type is characterised by its dominant tones of feeling. We have also noted that highly emotional states tend to interfere with the due activity of intellectual processes. Some individuals are incapable of effective intellectual work, owing to excessive emotional accompaniments. Others, again, have little intellectual emotion, and follow their pursuits with little or no emotional tone of feeling. The close con- nection between feeling and intellectual activity, and their mutual furtherance and hindrance, is liable to certain excep- tions. Thus, some individuals possess finely developed intel- lectual activity with the keenest power of abstract thought, who, nevertheless, are deficient in one or all of the higher emotions, such as the moral sentiment, or the love of truth. In psychological works much attention has been devoted to the correlations between states of feeling and certain bodily accompaniments, and innvimerable examples have been given of the bodily manifestations with which the mental states are supposed to coincide. Many writers uphold the view, that when the physical manifestations of a feeling are cut off, the emotional excitement is greatly checked, and tends to subside. That this holds true in some forms of melancholia -with agitation, is evidenced by the fact, that mechanical restraint is often attended by relief of the mental distress. Such patients not uncommonly request that their actions may be restrained, and they volunteer the statement that the mental relief is the result of the inhibition of their physical activities. In resistive melancholia, on the other hand, any attempt to control the move- ments sometimes results in an increase of the mental distress. The relation of the expression of misexy to the actual existing state of mind in an insane individual is always interesting. Those physical changes which have concomitant DISORDERS OF THE FEELINGS AND EMOTIONS. 395 sense-feelings, including the movements of expression which are partly instinctive, partly acquired, not infrequently outlast the emotion in duration, so that the expressions themselves become continuous or automatic, whilst the mind derives its emotional tone from other sources. Everyone who has to deal with the insane can recall instances of movements expressive of misery occurring coincidently M'ith pleasurable emotions. In such cases, the continuation of the emotion and of its expression along the same mental and physical lines respectively, result in a wearing out or subsidence of the former, and an automatic or unconscious repetition of the latter. Spencer believes, that as the feeling rises in intensity it engages mviscles of larger and larger calibre. Volkmann* points out, that the uncontrolled expression of a feeling tends to expedite its subsidence. This he explains by the consideration, that the movements carried out in this case cause a loss of intensity in the sensations accom- panying the emotion. We are unable to confirm the theory of Bain, that pleasure is connected with an increase, and pain A\ith a decrease, in the vital energies. One has only to walk through the wards of an asylum to arrive at the conclusion, that euphoria and malaise are not proportionate to vital activi- ties ; at least, not so far as the expressions of the vital activities are concerned. In the insane, many emotional states are found to be associated with some delusion which has obviously been deter- mined by morbid physical conditions. Thus, one individual now in Bethlem is depressed because he believes that he was formerly made of chalk, but now, since taking some vinegar, he is " only in solution," and fears he may be emptied away. This patient was a chemist, and was aware that he had taken chalk mixture on former occasions. In such instances, the question naturally arises, How far may the character of the delusion be attribtited to the emotional tone, or vice versa ? We have already seen that emotional tone in the insane can scarcely be conceived upon Wundt's scale of intensity of excitation, nor can we elucidate the occasion of painful states by an analysis of stimuli, appropriate or otherwise. In general, we conform to the law, that pleasure depends on a due balance between the * "Lehrbuch der Psychologie," vol. ii. § 129. 396 DISORDERS OF THE FEELINGS AND EMOTIONS. process of stimulation on the one hand, and that of reinvigora- tion on the other ; or between the expenditure and the accumu- lation of energ}" ; but when we view the morbid states of feeling- arising in connection with exhaustive diseases, and note the insane euphoria and exaltation that accompany the progressive depression of the vital functions, we feel that there is something more than the accumulation and transformation of potential energy into living force. The law of Weber in relation to the ratio of increase of stimulus to that of sensation, has been pointed out by Fechner as bearing a certain analogy to the ratio of in- crease of pleasurable stimulus to increase of pleasure. In the melancholiac, the greater the depression the greater is the amount of depressing influence necessary in order to produce a perceptible increase. In some hysterical and h3^pochondriacal persons the accommodation of the mind to painful impressions, in time results in an acquired liking for what was formerly disagreeable. Thus, just as the soimd of the bag-pipes may primarily affect us in a disagreeable manner, but ultimately become pleasurable, so the experience of a painful emotion may by repetition become essential to, and form part of, a mental state that is pleasurable. It is familiar to everyone how the melancholiac or hypochondriac will " hug " his delusion, and resent any cheerful interpretation of his feelings. With the repetition of sensations and ideas, with their accompanj^ing tones of feeling, be the}'- either pleasurable or painful, there arises habituation; and removal of the customary stimuli is attended by a corresponding want or negative pain, which has been termed " craving." The effects of change and habit on pleasures and pains form an interesting study, but one to which, in a work of this description, we are unable to devote attention. The intimate connection between the activities of the various organs of the body, and the tone of feeling associated with the perception of those activities, furnishes us with innumerable data whereon we might base many descriptions and possible explanations of the morbid phenomena in the insane. It must suffice, however, to recognise, that the activity of any organ does not necessarily coincide with the tone of feeling prevailing at the time. VARIOUS DISTURBANCES OF FEELINGS, 397 We have devoted a considerable amount of attention to the sense-feelings, and we have discussed the nature of the relation between the sense-organs and the mind. It will be un- necessary, therefore, to revert to this subject. In the insane, and more especially in hypochondriacs, there is often a morbid intensification of the organic feelings ; and where these are susceptible of localisation, their import is generally exaggerated or misinterpreted. In regard to the various disturbances of feeling most commonly met with, we may note the following as the normal foundations from which variations occur : — The feelings proper (emotional). The feelings referring to the will (volitional). The feelings bearing upon thought (intellectual). Mixed feelings, including forethought, desire, and relief.* The feelings of Jiapi/iness ov miser i/ are derived from physical and mental agencies. On the physical side, we have the various causes already enumerated; on the mental side, we have numerous examples of a degree or intensity in the happiness or misery. General paralytics usually receive sensations and revived impressions in the aggregate as pleasurable. Similarly, acutely maniacal patients are affected pleasurably rather than painfully. Melancholiacs, on the other hand, seldom experience pleasurable emotions, and, in the aggregate, their sum total of feeling is painful. Indifference to pleasure or pain is seen in the demented, the stuporose, and in the advanced general paralytic. The volitional feelings are subject to morbid per- versions, as seen in those who are unable to control their morbid cravings, desires, or lusts ; or in those who suffer from conflicting operations of the will. Intellectual feelings, or feelings associated with intellectual pursuits, may be absent or morbidly exaggerated. The mutual furtherance or hindrance of the two activities is evidenced in every asylum. Broadly speaking, the male lunatic's intellect perverts his feeling ; whereas the female lunatic's feeling perverts her intellect. The former feels becaiise he knows, and therefore believes ; the latter feels, and therefore both knows and believes. The one says, " I know. It is not a question of feeling." The * Bain, " Mental aiii Moral Science," p. 217. 398 DISORDERS OF THE FEELINGS AND EMOTIONS. other says, " I feel — therefore I know." The practical outcome of this broad generalisation is evidenced in the fact, that rational treatment by logical methods is sometimes effective with the former, seldom of any use with the latter. ]\Iixed feelings involve memories of past events and former mental states. As pointed out by Bain, the state of desire grows out of the retentiveness of the mind for pleasure or pain. Con- ditions of belief are sometimes dependent merely upon feelings of the mind, and with their development the intellect has had little to do. Let us now, however, look more particularly at some of the morbid emotional conditions met ■ with in the insane. For ■convenience, we will note those perversions associated with : — I. Sense-feelings. (a) Connected with bodily existence (health, depres- sion, hunger, etc.) (/') Organic (feelings of special sense). (c) Inner sense (temper or high spirits). II. Feelings connected with ideas. (ft) Ideas from sense (disgust, sympathy with pain). (b) From imagination (hope and fear). (c) From understanding (shame, reproach, etc.) (d) The gesthetic feelings (physical beauty). III. Intellectual feelings. (ft) From acquiring knowledge (pain of idleness). (I)) From intellectual exercise (novelty, system, order, symmetr}^ harmony, rhythm, simple and com- plex, Avit and humour, comic and ridiculous). IV. Kational feelings. (ft) Truth feelings. (h) The higher aesthetic feelings. (c) Moral feelings. (d) Sympathetic feelings. (e) Religious feelings. The feelings associated with bodily existence in the insane have much to do with the colouring of the mind. The true bodily state Avhich most favours a feeling of health is that in which organic sensations are absent. The transition from a jjainful state to one which is pleasurable — e.f/., the feeling of SENSE-FEELINGS. 399 satisfaction when hunger is appeased — does not negative this general statement. Further, other things being equal, the existence of a positive organic sense-feeling is attended by a proportional feeling of uneasiness or displeasure. In the sane person, therefore, visceral consciousness is proportionately painful. In the insane, the dominant feeling existing at the time may override or even obliterate the natural accompani- ments; so that a positive organic sense-feeling becomes dis- tinctly pleasurable. Thus, in general paralysis, we have seen many examples of exaltation and feelings of satisfaction derived mainly through the existence of morbid visceral states — e.g., one patient suffering from constipation derived extreme satisfac- tion from the belief that he was the happy possessor of " millions of fseces." Another, suffering from anasarca, magnified his abdomen into the " abdomen of the Deity," and exhibited it with great self-gratification. In general paralytics, the organic sense-feelings, which are symbols of hunger, are sometimes absent. Such patients fail to appreciate when they have had enough food, and exhibit a boulimia, which is characteristic. Some idiots are unha^Dpy unless there is complete distension of the abdomen by an excessive supply of nutriment, and instances have been known A^-here the conditions of rumination are essential to the feelings of well-being. The morbid exaggerations and excessive emotional accom- paniments of the activities of the special senses, are well illustrated in some forms of hysteria. The emotional displays associated with unstable temperaments are often suggested by some simple sense-feeling. Thus, music is in some instances a potent factor in causing an outburst of emotion. The unecjual development of the special senses, and the fact that cultivation of one sense in excess of the others involves M'ith it feelings of a n]ore advanced and suggestive order when that sense is active, helps to explain the sensory side of the many varieties of the special sense-feelings. In degenerative cerebral states, it is not uncommon to have a partial exaltation of feeling associated with the activity of a special sense ; especially in the early stages of general paralysis and organic or senile dementia. In acute mania, there is often, with the hyperaesthesia of the senses, an exaggerated emotional accompaniment. In melancholia, in 400 DISORDEKS OF THE FEELINGS AND EMOTIONS. confusional states, and in anergic or melancholic stupor, the emotional accompaniment proj^er may be defective or entirely absent. Those inner sense-feelings known as temper, high or low spirits, are met with in every degree of intensity in the various forms of insanity. In some forms of idiocy, as in the Mongol or Kalmuc, continuous amiability and placidity are noticeable. In monomaniacal states, there is frequently a stability of the inner sense-feelings, in striking contrast to the nature of the delusions — i.e., there is no proportional feeling accompaniment. In hereditary neuroses, instability of the emotional side of mind is a noticeable symptom. Individuals who have inherited a neurotic diathesis are often subject to the periodical prepon- derance of sorrowful or depressed feelings, or feelings of a gay or expansive kind. In senile decay, the emotional element is often perverted. An attack of senile mania may be ushered in by emotional instability without any obvioiis enfeeblement of the intellectual faculties. Depression of spirits may precede an attack of senile mania. The emotional disturbances may or may not be symptomatic of the onset of dementia due to gross lesions of the cerebrum. In cerebral atrophy, focal lesions, liBemorrhage, or thrombosis, the perverted state of the emotions is sometimes characteristic. Bevan Lewis draws attention to the diagnostic distinctions between simple senile depression as a purely func- tional ailment, and the depression which indicates a serious structural change in the nervous centres. He found, that in the forms of simple melancholia, unaccompanied by any delu- sional state, there was a strongly-marked suicidal tendency in 79 per cent. In general paralysis, the emotional condition is also charac- terised by its instability. The prodromata of the disease may consist in emotional depression or excitement ; the two condi- tions may alternate, each state being determined by insignifi- cant causes. Sooner or later, however, the condition of euphoria predominates, and later that of complete absence of emotional tone. Those feelings connected with ideas in part derived from the senses — e.g., disgust, etc. — are seen chiefly in the so-called delusional insanities. The utter contempt with M"hicli the SENSE FEELINGS. 401 victims of imagiiiaiy plots treat others around them is often a noticeable feature of asylum life. With such patients no attempt is made to conceal or control their expressions ol' disgust. On examination, some sense-perversion is usually found to account for the conduct. It may be due to an imaginary persecution by means of drugs or other substances, or there may be some delusion about the moral attributes of others. Sexual ideas give rise to mkny expressions of disgust, and in every asylum there is some individual who attributes unworthy motives or actions to those in attendance. These un- controlled expressions, sometimes of actual loathing, are seen even in idiots, who make false accusations of immorality and disgusting conduct in others. In melancholiacs, the intense feelings of disgust are sometimes the outcome of ideas of un- worthiness relating to themselves. Such patients refuse to shake hands, recoil when approached, and adopt every means within their power to avoid contaminating others. Similarly, the hypochondriac with ideas that he is suffering from a foul disease, that his breath is offensive, that he is covered with vermin, etc., will hold himself aloof from others, and avoid all possibilities of contact. In adolescent mania with exaltation, just as in the evolution of conceit, the individual will often treat his superiors with contempt. Such conduct, however, is as common outside asylums as within. The absence of feelings of disgust is also characteristic of some forms of insanity. Thvis, in some forms of mania there is loss of all the higher feelings of cleanliness or decency. Similarly, in states of dementia, melancholia, or stupor, there may be absence of attention to the ordinary conventionalities of society or the decencies of life. It is not uncommon to meet with cases in which this absence of conventionalism is the only characteristic feature of the mental attack. In idiots the moral side of the question may be defective from the beginning. In insanity it may be symptomatic, or it may remain as a sequel after an acute cerebral attack. In general paralysis it is some- times seen in an extreme degree. Sympath}^, depending as it does upon a fine observation, rightness of interpretations of the objective signs, the recalling of past personal emotions, and the constructive imagination, is 26 402 DISORDERS OF THE FEELI-NGS AND EMOTIONS. liable to defects or perversions, through absence, excess, or alteration of one of these factors. Some individuals possess an intense emotional temperament, and are susceptible in an exaggerated degree to the influence of the emotions of others. Others are deficient in emotional capacity and have little or no sympathy. There is a large field for study in the emotions of the insane. We may say briefly ; (1) Emotional and sympathetic states may be evidences of a natural temperament in the sane ; or their existence may be symptomatic of mental perversion. Thus, the emotional susceptibility of a normal character in one individual may, in another, be unusu'al and pathological. In determining the value of the affection of the sympathetic capacity as a sign of disease, comparison must be made with the life history and emotional tendencies of the individual. Benevolence and pity may be natural or morbid. It must not be forgotten, however, that in some forms of mental disease (e.g., general paralysis) the wide sympathies and benevolence mav be the mere exaggerations of a natural temperament. (2) Fineness of observation has much to do with the absence or excess of the sympathetic feelings. Eeference to the preceding chapters upon the senses will enable the student to appreciate, that just as the cognitive state varies with the functional . activity of the senses, so the accompanying tone of feeling may be proportionately varied. In conditions of anaesthesia or hypersesthesia the sympathetic feelings, other things being equal, will more or less coincide with intellectual interpretation of the presentations. (3) The mind's interpretation of the presentation is a factor of much importance, and the sympathy will varv with the rightness of that interpretation. We have already discussed the factors which give rise to abnormal inter- pretation, so that it is unnecessary to return to the subject, (4) The recalling of past experiences is productive of morbid exaggerations, or the reverse. Thus, just as want of sympathy with the emotional experiences of the young is in great part due to the fact that we have forgotten our experiences when children, so the apparent callousness of the general paralytic, the alcoholic, or the senile dement, is in part due to an amnesic state and inability to revive the emotional experiences of the IDEATIONAL FEELINGS. 403 past. That the sorrow of another should engage our sympathy it is essential that we shonld be able to compare the cause and effects of that sorrow with our own experience. (5) In addition to the revivability of our own impressions and their emotional accompaniments, constructive imagination is an im- portant factor. Absence of this prevents a correct interpreta- tion of the feelings of others. Exaggeration, on the other hand, betokens a susceptibilit}" that is morbid. The absence, excess, or perversion of the sjnnpathetic feelings, when viewed as the outcome or accompaniment of the various cognitive states, is a subject which might be dealt with at greater length. Those feelinf/s connected irith ideas of hope and fear, involve a considerable amount of imagination. The hopes and am- bitions in the insane are capable of modification. We have already pointed out, that the hopes which arise during periods of distress are sometimes realised by the general paralytic, and that the realisation is illusory, indicating thereby a process of dissolution. The illusory hopes of the phthisical are well known. Similarly, in chronic cerebral diseases, the condition of buoyancy and hope may be symptomatic. In adolescents we meet with every degree of hope, from mere desire to com- plete confidence and assiirance. In old maids and others, the non-realisation of long-sustained hopes may result in a de- spondency that is morbid. In unstable temperaments, there is often rapid fluctuations between states of hope and de- spondency.* * To the morbid states of fear numerous names have been given. Ama.vo- phobia signifies a morbid fear of being in a waggon or cart ; clcmstrcqjhobia, fear of being in any closed space or chamber; butophobia, a morbid fear of heights ; agorapjhobia, a fear of open spaces. Beard (" Tuke's Diet.," p. 844) has classified certain conditions of fear according to their causes, as follows : — monophobia, fear as such ; unthropjophohia, the fear of being with others; pathophobia, the fear of becoming ill; pantophobia, fear of everything ; astropjhobia, fear of lightning ; rKjxphobia (verga), the fear of being dirty ; siderodromopjhobia, the fear of going by train ; nyctophobia, the fear of night ; pAobopjhobia, the fear of becoming afraid. Arndt suggests that were we to carry this absurdity further, we might distinguish a much greater number of conditions of fear: skopophobia and Mopsop)hobia, the fear of spies and thieves ; t]ianatophobia, the fear of death ; necropjhobia, fear of the dead and of phantasms ; triakaidekaphobiu, the fear of number thirteen, etc. 404 DISORDERS OF THE FEELINGS AND EMOTIONS. The feelings of shame, reproach, etc., may be absent, or morbidly intensified. The maniacal person suffers little from feelings of shame. In idiots or imbeciles this feeling may be entirely absent and incapable of cultivation, so that, sooner or later, the condition known as moral insanity is developed. In acute attacks of mental disorder there may be complete absence of shame or self-reproach ; the unconventional, both in language and conduct, manifests itself as a symptom of the disease. In melancholiacs these feelings are usually morbidly active, and self-condemnation is rather the rule than the ex- ception. Introspection, or rise in the subject-consciousness, is a prominent factor in the production of a painful conscience. To " know thyself," is to suffer shame and endless reproach. In asylums those individuals who have a tender conscience often know themselves better than do the sane. It must not be forgotten, however, that a morbid introspection may be productive of false accusations and needless remorse. The lower cesthetic feelings connected with the appear- ance of the body, may be considerably perverted in the insane. In states of melancholia, mania, or dementia, there may be absence of all personal cleanliness and care ; or, as in general paralytics, exalted maniacs, and monomaniacs, there may be exaggeration of the lower aesthetic feelings, ranging in degree from extreme care and eccentricity, to decorativeness and dandyism. Iii the eyes of some maniacs and general paralytics every object assumes the charm of beauty; while the persecuted and melancholiac may view everything as ugly or loathsome. The {ntellectual feelings derived from the acquisition of knowledge, are familiar to most of us. This tone of feeling once developed is associated, during its temporary absence, with an intensification of the pain of idleness. On the other hand, so great may be the desire for knowledge, and so intemperate the methods of acquiring it, that the emotional tone may be exhausted and distaste result. In the insane, the engagement of the emotions in some other direction acts as a deterrent from any intellectual activity. Hence it is, that those who are morbidly introspective, or hyperattentive to their dominant ideas, are necessarily unable to apply themselves to ixny consideration requiring intellectual effort. RATIONAL FEELINGS. 405 The rational feelhujs — those feelings associated with truth, morals, and religion — are sometimes absent, exaggerated, or perverted in the insane. Until Prichard described affections of the moral powers as occurring without obvious impairment of the intellect, it was doubted whether there was such a condi- tion as moral insanity. Hack Tuke succeeded in convincing us that moral insanifi/, without any obvious intellectual impair- ment, does exist in certain individuals. Moral deficiencies or perversions may be determined (1) primarih^by internal factors through inheritance. Some children inherit dispositions in which the moral sense is incapable of development ; others betray the existence of an immoral tendency during childhood, and, in spite of training, remain incorrigible. (2) Moral per- versions may be evolved gradually ; they may be the outcome of special social influences, or the result of some slight cerebral disturbance or disease. Hack Tuke demonstrated that it may be practically impossible to detect the intellectual flaw, and yet a physician may be driven to decide that a person is insane. (3) Moral insanity may show itself as a precursor of other forms of insanity. Thus, it may precede delusional states ; it may occur as an early sign of general paralysis or senile insanity ; it may also show itself as an early symptom of an acute maniacal attack. (4) Moral insanity may exist as a sequel to a cerebral attack. Thus, cases have been observed where moral defect has remained as a sequel to sunstroke, febrile delirium, cerebral syphilis, and acute mania. (5) Moral insanity may exist as an associative phenomenon with brain disease, or with other diseases which affect the brain and its membranes. (6) Other causes, such as alcohol, masturbation, amenorrhosa, parturition, lactation, etc., may determine a loss or perversion of the moral sense, without obvious change in the intellect. (7) In an unstable nervous system a moral or physical shock may determine a moral disorder. (8) In epileptic states the moral nature may be affected without affections of the memory or intellect. Clinically, we have to note the following forms of moral insanity: (1) In children there may be absence or precocity of the moral feelings. Such conditions may be manifested by affections of the sexual instincts, homicidal ten- dencies, wanton cruelty, lying, stealing, masturbation, and pyro- 406 DISORDERS OF THE FEELINGS AND EMOTIONS. manias, etc. (2) In adults, we have to note, the morbid cravings for intoxicants, homicidal and suicidal tendencies, pyromanias, kleptomanias, the conditions of moral languor, the morbid religious emotions, and moral dislikes and prejudices. Hack Tuke held, that the theory of the existence of moral insanity, apart from intellectual impairment, is in full accord with the principles of mental evolution and dissolution as laid down by Herbert Spencer. After a careful consideration of the psychological and clinical facts he made the following- propositions : — " (1) The higher levels of cerebral development which are con- cerned in the exercise of moral control — i.e., ' the most voluntary ' of Hughlings-Jackson, and also ' the altruistic sentiments ' of Spencer — are either imperfectly evolved from birth, or, having been evolved, have become diseased, and more or less functionless, although the intel- lectual functions (some of which may be supposed to lie much on the same level) are not seriously affected ; the result being that the patient's mind presents the lower level of evolution, in which the emotional and automatic have fuller play than is normal. '^ (2) No doubt it is difficult to lay down rules by which to differ- entiate moral insanity from moral depravity. Each case must be decided in relation to the individual himself, his antecedents, education, surroundings, and social status, the nature of certain acts, and the mode in which they are performed, along with other circumstances, fairly raising the suspicion that they are not under his control."* In concluding this chapter we may mention that, disorders of feeling may occur at all or any periods of life. In childhood or at puberty, the usual emotional accomj)ani- ments of the physical or mental evolution ma}" be absent, perverted, or morbidly intensified. During the periods of adolescence, climacterium, prime, or senescence, emotional in- stability may manifest itself. In the female the emotions are liable to be upset during pregnancy, parturition, and lactation. Idiots and imbeciles display every kind of emotional disposition. Some are good-tempered and happy, others are irritable and morose. Undoubtedly, many of the criminals in our jails are of the imbecile class, and, in the commission of their crimes, they have been more or less unconscious agents. Ireland says, that idiots and imbeciles seem to be much more expert at taking up moral relations than one would suppose from their * Vide " Tuke's Diet.,"' j). 813. NATIONAL FEELINGS. 407 other deficiencies. " They attach praise and blame to particular people and to particular actions. They are accessible to pity, and still more to affection. The better classes of imbeciles can often be induced to make considerable sacrifices for the happiness of others, giving away, for example, things which they like, and preferring the pleasure of seeing others enjoy them. . . . The lower class of idiots have no religion. Imbeciles can be taught the existence of a Superior Being, though their ideas thereupon are childish, and have a tendency to become anthropomorphic. Some imbeciles take up the notion of responsibility to a higher power, which distinguishes the religious man from the simply moral. They can learn the biographical and historical parts of Scripture, the precepts in the Gospels, and the parables ; but it is vain to try to teach them doctrines such as those contained in the Shorter Catechism or Thirty-nine Articles, which they neither can remember nor comprehend." Idiots of the Mon- golian or Kalmuc type are usually affectionate and cheerful. They are good mimics, and fond of music. Seguin and others suggest that these types are connected with some form of hereditary cretinism. In sporadic cretinism characterised by the presence of fatt}^ tumours in the posterior triangles of the neck, and in many instances absence of the thyroid gland, there is usually a good temper ; but the higher emotions are little developed. In endemic cretinism the emotions or tones of feeling may be entirely absent; or, in the higher grade (semi-cretinism), there mav be an emotional accompaniment to the vegetative or animal instincts, or to the impressions of the special senses. In the still higher grade {crC'tineux), the exercise of the intellec- tual faculties may be attended by a corresponding emotional tone. Just as there is no constant relation between the deg'ree of intelligence and the weight of the brain, so there is no relation between the feelings and the size of the head. It is not uncommon to meet with microcephalic, hydrocephalic, or scaphocephalic idiots, or idiots with cerebral hypertrophy, who possess emotional characters differing little from ordinaiy human beings. Sometimes they enjoy a joke, sympathise, and form affections out of all proportion to the amount of their intellectual development. Cases have been recorded in which all the special senses in the microcephalic idiot have been 408 DISORDERS OF THE FEELINGS AND EMOTIONS. developed to an exquisite degree, and, with the development, also a corresponding tone of feeling. Some idiots, like som^e sane people, have little intellectual power, but acquire a religion through imitation and habit. In hereditary epilepsy the epileptic attack is often preceded by irritability or by an emotional outburst. Sometimes the fits are followed by a tendency to cruelty, pyromania, etc. Meschede* has described such a case due, according to him, to an osseous growth upon the clivus, with consequent inflam- matory affection of the adjacent membranes and nervous tissue. The period of puberty is attended with marked physio- logical and psychological changes. Associated >vith the de- velopment of the genital organs, there are awakened the sexual instincts and all their corresponding emotions. In the female, we have to note the occurrence of hysterical attacks, and those mental manifestations of the development of the sexual organs. In the male, on the other hand, the emotions iindergo little change at this period. At the period of adolescence, howev^er, he undergoes a mental evolution, with which there is developed an egotism that sometimes passes the border line of sanity. The psychology of puberty and adolescence forms an important study, and one that ought to commend itself to all of us. We do not understand the phj^siological side of the special evolution of the emotions at this period, nor are we aware that any attempt has been made to analyse it. For an account of the various disorders of feeling occurring at the different periods of life, the student is referred to text- books on insanity. It only remains for us now to state, that emotional perversions may be symptomatic of such states as mania, melancholia, or even of mental enfeeblement. The emotional distiirbance itself may or may not be the only in- dication of unsoundness of the mind. Absence, exaltation, or perversions of the emotions may be symptomatic of degenera- tive states, such as general paralysis, paralytic or senile dementia, or epilepsy and its allied states. * " Zeitschrift fiir rsycliiatrie," xxix. Band. 1 Heft. 409 CHAPTEE XIII. I'HE Will. r)efinition — Deliberation — Choice — Resolution — Self-determination — Delayed Reflex — Influence of Habit — Desire — Psycho-Physical Processes of Volition — Volition not to be explained Anatom- ically, Physiologically, Developmentally, or Pathologically — Reflex Acts — Periphero-Motor — Centro-Motor — Automatic Acts — Voluntary Acts — Motor Images — The Will Power in Hypnosis — The Feeling of Effort — Introspective Evidences — Physiological Inhibition — Nervous Resistance — Movements — Central — Peri- pheral — Simultaneous — Sequential — Speech Movements — Dis- orders of the Kinsesthetic Word Apparatus — Deaf Mutism — Acquired Defects of Speech — Alliteration — Verbigeration — Akataphasia — Speech Defects in the Insane — In Sleep and its Associated Conditions — Conduct — Nervous Mechanism of Con- duct — Conclusions as to the Existence of a Will — Impairment of Will Power — Irresolution — Defective Impulsion — Excess of Impulsion — Defective Voluntary Attention — Absence of Will — Conclusions. THE WILL. To those active operations of the mind which involve move- ments and active concentration of the attention upon an object or idea, with the addition of a resolve, the term " will " is applied. Such vohmtary operations involve a purpose, and the movements are consciously directed towards some end. Volition is sometimes regarded as only a moi'e energetic form of desire, inasmuch as it engages the muscular system as well as the motor centres. Expressed psychologically, volition is the revival or repi'esentation of former presentations which have been accompanied by feeling; the representation, if painful, is avoided ; if pleasurable, favoured. Coupland describes will 410 THE WILL. as the act of striving to procure a pleasure or to suppress a pain. The same author regards the term " deliberation," if taken too literally, as misleading, because it is apt to suggest that the human subject of the representations is passively affected, whereas, the experience and organised nature of the subject are themselves all-important factors in the case. The human being possesses an organised nature which responds to its environmental influences. The nature of that organism, and the nature of that environment, determine the characters of the representations. Under the competing influences of such representations, action may be delayed until one representation gains the ascendency. The action which follows upon this delay is termed " voluntary," the delay is " deliberation," whilst the term " choice " symbolises the com- paring of ends, and "resolution,'" the ascendency of one end or motive over the others. When we trace the origin of the phenomena included under will, we find that there is no hard and fast line of demarcation between the so-called " appetitive action," and the highest forms of purposive action or self- control, which manifest themselves as voluntary only, after passing through the stages of deliberation, choice, and resolu- tion. Before discussing the questions of the sense of effort, and the adjustments of the motor apparatus involved in the active operations of the will, it is essential that we should know something about the speculations which have been made as to the existence of a free will. Since Plato made the distinction between voluntary and involuntary mental activities, the discussion as to whether the will is self-determined, or- whether it is necessitated, has engaged the attention of every psychologist and moral philoso- pher. The older writers, such as Plato, Aristotle, the Stoics and Epicureans, however, did not discuss the problem of freedom in the same way as did the Neo-Platonists, and the Christian apologists of the second century. The latter writers supported the view, that freedom consisted in independence from external causes. The mind itself was regarded as possess- ing perfect freedom of choice between good and evil. Some idea of the theological aspects of the question may be gathered from the writings of St. Augustine, Aquinas, Calvin, Pelagius, FREE WILL THEORY. 411 Arminius, and others ; while the philosophical relations have been treated by Hobbes, Descartes, Locke, Leibnitz, Clarke, Edwards, Priestley, lieid, Hamilton, Stewart, Mill, and others. The doctrine which implies that the ego is in itself an active principle, is one which we are compelled to leave to philosophy or metaphysics. We have not the means of testing- po\^-er or final causality ; we can only base our views upon the observable phenomena or facts of volition within ourselves or others. The ethical side of the doctrine is of course of immense importance, inasmuch as it obviously influences the theory of moral re- sponsibility. The modern tendency is to regard the will, or rather the active expression of the will, as a delayed rejiex. The delay is brought about by the co-operation of reflection, which serves to modify and protract the ultimate resokition upon which the appropriate action depends. This ultimate resolution is re- garded as dependent upon some impulse or idea bearing a relatively greater degree of intensity than the other factors deliberated upon. Volkmann* regards the power which reveals itself in the final volition as being no po^\'er above the repre- sentations, but only a new revelation of the powers working in the representations, and he believes that the final volition gives the advantages to one of the contending volitions, or perhaps suspends both. This he explains by the fact, that this very volition proves itself ultimately to be the resultant of the collective internal movement. Sully adopts a somewhat similar view, and believes that in every case the action is the resultant of the factors ultimately engaged. Later, we shall see that the characteristic manifestations of " will" are to be explained as the results of habits organised in the individual, and transmitted to the progeny, either as a tendency to react readily, or as a tendency to deliberate before acting. In any case, the psychical and physical factors acting at the time determine the individual or particular reaction characterised as the effort of will. It is unnecessary to point out that all active operations of the mind involve an intellectual and emotional element, and that just as there is an opposition or furtherance of the states of knowing and feeling, by reason * " Lehrbuch der Psychologie," vol. ii. p. 456. 412 THE WILL. of their mutual relations, so there may be a mutual furtherance or hindrance of activities of the will by reason of its relation to the states of knowing and feeling. As Sully puts it, " The outgoings of the mind in action, involving the excitation or ' innervation ' of the motor nerves and muscles, are incom- patible with the comparatively passive state of observing something or thinking about something, with its physical accompaniment of bodily stillness. The man of energetic action is popularly contrasted with the man of reflection. Similarly, strong emotional excitement and action are incom- patible, and the man of strong will is one who, among other things, brings emotion under control." A full account of the nature of willing would include (1) the primary presentation with its accompanying tone of feeling; (2) the representative process, with the realisation that the revived process forms a step in the experience of the ego; (3) the struggle for existence among the representations when reviewed by the erjo; (4) the deliberation upon the qualitative aspects of the representations; (5) the conscious choice of a desired representation; (6) the belief in the fitness of the action to acquire the desired end; (7) the resolution to acquire the de- sired end; and, lastly, (8) the revival of the appropriate image, and the action which is believed to lead to the desired end. With the growth of experience, the instinctive impulse of the child to avoid pain involves more and more of the repre- sentative element, until the consciousness of recoiling from Avhat is painful becomes a desire to avoid it in the future. Thus, desire becomes an essential element in all voluntary action. Without the representative element, there is little or no desire. In addition, the representative element must be accompanied by a revival of the primary tone of feeling, other- wise, desire disappears. When the revived tone of feeling is morbidly intense, or when it is inferior to the primary tone, there may be a feeling of craving for the actual realisation. The absence, exaggeration, or perversion of the representa- tive elements of desire may be the primary factors in the development of the morbid apathies, and the excessive or abnormal volitional activities of the insane. Similarly, failure in the revival of the tone of feeling that accompanied the FREE WILL THEORY. 415 primary presentation, may result in an apathy and absence of desire. The melancholiac or the maniac may be unable to recall the feelings of love for home and its surroundings, and apathy or indifference results. There is no desire to recover or to return to their homes. The alcoholic dement may be deficient in desire, and consequently in volitional activity, by reason of his defective memory. Similarly, in dotage the characteristic amnesia may account for the failure of desire. When we desire a thing we are apt to concentrate our attention upon it, so that its representation assumes the character of a dominant idea. This concentration of the attention involves a certain amount of effort, which may become active tension or strain if the desired end is not realised. In this way we see how the motor or bodily element comes into play, either as a distinct voluntary or anticipatory adjustment, or as an imaginary representation of bodily movement. The degrees of intensity of desires, and the range of movements prompted by them, as manifested in the insane, form a subject so extensive that \^^e cannot enter upon it here. It must suffice to know, that just as sane individuals are indolent or active according to their moods or temperaments, so the insane present every degree of activity from apathy and anergia to active impulse and maniacal violence. When ^ve survey the endless controversies of the evolution- ists, both biological and dialectic, which have for their object the identification of desire and will, we fail to understand from the analogies of lower life how the will, the volition, the conscious guidance, or call it what you will, comes into existence at all as a factor of mental life. Here we must confess that the intelligent activities of ethical life do appear to indicate the existence of a rational principle. The ultimate locus standi of the moral intuition is, however, beyond the grasp of science. Whether we regard the \\\\\ as a separate faculty or a part of the mind as a whole, we must be struck with the fact, that neither intellect nor emotion can direct itself or govern the mental life of the individual without the aid of the intelligent self-determinating influence denominated will. We do not hold with Kant's transcendental theory of the cognition of moral law, that the will stands as a faculty of determining 414 THE WILL. oneself to action in accordance with the conception of certain laws, and that such a faculty can be found only in rational beings.* It is well nigh impossible to mark the point of transition from animal life to the so-called rational life. In other words, we do not know where thought-determined activity comes in in the animal series. The transition bet\^'een impulsive and reflective activities is to be as readily traced as the. transition between primary sensations and repre- sentations. An adequate philosophy must posit the reflective activities as the outcome of the impulsive at the verj beginning of sentient existence. Those activities which go to constitute Action, and are uniformlj^ pi'esent in conduct, are not the exclusive property of mankind. When we try to account for the origin of the modification of consciousness, known as deliberate piirpose, and confine its existence to man, we render ourselves open to a discussion upon the main problem of animal life and conduct, and, at any rate from the empirical point of view., we have to begin at the very beginning. Whether the soul possesses an independent energy, which makes the individual the source of activity, and, therefore, reasonably and justly responsible for his conduct, is a matter of individiial opinion. The materialist scoffs at such an idea as absurd. He sees the mind as the outcome of molecular activity. The spiritualist, on the other hand, views the mind as independent, or as being but a lesser manifestation of an all-pervading archetypal essence of true morality or rationality of action. The former pictures the mind as a result of infinitesimally minute atomic movements. The latter pictures an all-pervading mind as the guiding power of an infinite cosmical activity. In both, hypotheses are scientifically of no avail. The ultimate nature of both series of events is transcendental to all the powers of human inquiry. We, as passive onlookers, view the empirical sides of the question, and can conceive, that if the infinitesimally minute atomic move- ments within lumbar ganglion cells can serve a higher centre with an activity which ultimately becomes symbolised as moral law, then so also can the infinite cosmical movements serve a universal mind. When we look through a microscope at a * Kant, "Metaph. of Ethics," chap. ii. NATURE OF WILLING. 415 minute nervous structure, we see the structure and imagine the movements of atoms which would correspond to mind. When we gaze at the vault of the heavens through a telescope, we see the innumerable worlds, and imagine a sensory and motor intelligence, which would correspond to the Deity. If movement is all-sufficient in the one instance, then why not in the other? We know nothing about a higher mind, it is true. But it is readily conceivable, that just as the atoms of a lumbar molecule may serve and obey a mind, of which they know nothing, so we, as atoms on this earth molecule, may serve and obey a mind, of which we also know nothing. When the student has once grasped the meaning of the mind and body, and has satisfied himself as to how much he really knows, and when he has reflected upon the nature and extent of the cosmos, he need never be accused of favouring the propagation of scientific dogmatism with regard to the Unknowable.* Some authors, and more especially those of the modern German school of thought, ai-e satisfied that they can deduce action from presentations, representations, and the laws of association. They ignore the assumption that there is an especial will as the cause of our actions. According to Ziehen, " When we will do something, our own psychical content at that moment is only distinguished from other psychical contents by the fact, that the idea of a desired action, accompanied by a positive emotional tone, is already contained among "the sensations and ideas that are then actually present." The same author gives the following order of events as occur- ring, when we say, " / will do something." The sentence, when spoken, is " a series of motor ideas of speech with which are associated (1) the ego-idea in the sense formerly discussed ; (2) the idea of a future act, accompanied by a positive emotional tone ; (3) motor sensations accompanying attention ; and (4) the idea of a causal relation existing between the ego-idea, and the desired action." Ziehen also makes the positive assertion, that the attempt to set up special diseases of the will under the name of monomania, or a general disease of the will designated as moral insanity, have all been recognised failures. He seeks to reduce all disturbances of voluntary action met with in * The consideration of the Dogmata of Faith is quite another matter. 416 THE WILL. insanity, to disturbances of the sentient life, especially of the emotional tone, or to intellectual disturbances — ile., disturbances of the ideas or of the association of ideas. We quite agree with him, that the loss of will-power may always be reduced either to the exceeding sluggishness of the association of ideas, to the abnormal negative tones of feeling, or to other similar afflictions ; but sve utterly fail to follow the reasoning ■^^dlich seeks to prove, that because one phenomenon can be demonstrated as dependent upon another phenomenon, therefore the one phe- nomenon is that other phenomenon. Were we to adopt his method of argument, we should be compelled to deny the assumption of a special faculty of the emotions, because that faculty is dependent upon cognitive states, and can be reduced to the terms of such states. Because one state can be demonstrated as the obvious outcome of another state is no reason why the two states should be held as identical. The phenomenon of the will is psychologicallj' as distinct from the intellectual and emotional faculties (although dependent ujjon them) as a new-born child is physiologically distinct from its mother (although dependent upon her for its origin). Were our task of analysing the nature of the will completed by the description of the intellectual states and their emotional accom- paniments, we would consider ourselves as mere automata responding to a force over which we have no control. The direction of our efforts would be turned like a weathercock, Avith every stimulus. It is just the conscious selection- of the most a2J2^ro2Jriate reaction to circumstances, and the rolitntary activitij thereby involved, that constitutes vhat is hnown as the will. It is significant that the most strenuous opponents of the theorj" of the will faculty are foremost in drawing a line of distinction between reflex and voluntary acts. Ziehen himself regards the reflex and automatic acts as the physiological, and the ideational acts as the psychological, antecedents of voluntary acts. Here again, we may repeat, that, although a condition can be resolved into terms of its antecedents, there is no proof that the condition itself is not present, but only the antecedents. Were such arguments possible with physiological or patho- logical problems, we should find ourselves involved in a PSYCHO-PHYSICAL PROCESSES. 417 disquisition upon the absolute inseparability of cause and effect. In the meantime we have to recognise that the terms, " volun- tary," " conscious guidance," " will," etc., can never be replaced by terms of intellection or emotion. Let us now analyse the Psycho-Physical Processes of Volition. — When we trace the evolution of the early move- ments of an infant to those higher movements termed volun- tary, we find that there are involved two sensorial elements — viz., the impressions derived from the special channels of perception, and the impressions derived from the movements (sense of effort, kinaesthetic auxiliary). Andriezen* regards the mode of evolution of each special or local sense as having been a twin evolution, a special kinaesthetic element having entered into it, and got incorporated with. it. " During the condition of attention," says Andriezen, " there is not only an increased functional activity in this or that sensory centre, but an overflow or discharge from that centre to others along definite routes, or diffusely all over its borders. Where a voluntary act or movement is one of the outcomes, the neural discharges consist of (a) primary sensation, focussing-reflex, attention ; and (b) discharge from such sensory centre, (c) with resultant excitation of other sensory or psychical centres, arousing feelings and mental images (ideas), or of a kinaesthetic centre, in the last case evoking a more or less obviously special movement. The sequence of events comprises, therefore, (a) arousing a sensory centre to attention ; and its discliarge, along {b) a tract to (c) a kinaesthetic centre ; followed by an appropriate move- ment to its completion, or, in psychological language, _/s/'.«^, perception ; second, apperception and attention ; third, strong revival in mind of the act to be performed ; fourth, execution of the idea. Attention thus belongs to the sensory side ; volition to a specialized and intensive discharge therefrom to the kinaesthetic sphere. Volition is thus a development from attention, and passes on to execution ; it is thus the passing from attention to execution : in the brain it overlaps the psycho- motor sphere on the one side, and the sensory on the other ; its region is, therefore, the transitional or association system one between these two. On the anatomic-physiological side we think the mixed pyra- midal or polymorphic system to chiefly represent this association region, partly on comparative and developmental grounds, and partly from pathological considerations. The gradual historical development and elaboration of this system in the mammal till it attains its acme in man, and the lateness of this lower cortical organisation to complete its growth in the new-born and young, indicate that this ' accessory * "Brain," 1894, p. 676. 27 418 THE WILL. association system ' of the brain is the chief structure which subserves the higher psychical functions, and especially volition. Further, of all the various cell systems involved in chronic alcoholism, it is the one in which the changes, especially the trophic ones, are most advanced." In the main, we are in accord with these views, so far as they go ; but, as we have seen in preceding chapters, we know nothing about the perceptive side of sensory impressions so far as their ultimate localisation is concerned ; nor do we know the regions concerned with the immediate transition of mental to motor events. If we assume, that within the higher psychical regions — the ultimate substratum of conscious- ness — the sensory elements are distinct from the motor, then we are justified in imagining an association scheme between the two. We are not aware, however, of any comparative, develop- mental, or pathological facts which would lead us to decide upon this question. The arguments advanced to prove that the " accessory association system " of the brain is the chief structure which subserves the higher psychical functions, and especially volition, may be valid as far as they go, but they give us no light upon the actual serving of the psychical func- tions. The student is urged to reflect upon the question as to how far we have got in our effoi'ts to trace a sensory stimulus to its terminal point in the cortex ; then, if he can, to satisfy himself as to the fons et origo of a highly developed motor im- pulse. When he has grasped the fact, that his knowledge about both series of events is inadequate, then he will be in a position to estimate the value of the various hypotheses hitherto advanced. Volition cannot be explained anatomically, physiologically, developmentally, or pathologically. The existence of voluntary activity, as viewed objectively and expressed psychologically, is as clearly manifested (in its rudimentary form) in the protozoon as in man. Certainly, the gradual historical de- velopment and elaboration of the nervous sj^stem has been coincidental with the empirical evolution of the normal will manifestations. But the actual conditions of reaction or initiatory transformations — to say nothing of many patho- logical affections of the will hitherto inexplicable by natui-al law — are, and doubtless will be. unknown to us. Ill an early chapter we briefly mentioned some of the EEFLEX ACTION. 419 differences between reflex and automatic acts. We propose now to study the progressive development of these acts, and to trace them to the so-called conscioiTS or voluntary acts. We are all acquainted with examples of conscious acts becoming automatic through repetition. The psychical ac- companiment becomes gradually less and less with each repetition, until finally there is no obvious psychical correlate, or the mind may be engaged in other directions. Ziehen divides automatic acts into two large groups, according to their development : (1) Those which have developed from reflex acts in the course of long ages and many generations — i.e., phylogenetically ; (2) those which are the product of vokintaiy acts during the life of a single individual — i.e., that have developed ontogenetically. Meynert attempts to prove that voluntary acts are derived from automatic. Mtinster- berg, on the other hand, tries to prove that automatic acts are derived from acts of the will. Automatic acts are more complicated, and present greater variability than reflex acts. In neither are there any psychical concomitants. An automatic act also resembles an instinctive act in this latter respect. On account of the great diversity of automatic acts, it is some- times difiicult to distinguish them from conscious or voluntary acts. Inasmuch as reflex and automatic acts do not involve a psychical correlate, their consideration falls more particularly to the physiologist. Phj^siologists have sought a mechanical cause for the various activities of life, and they have, to a certain extent, succeeded in enumerating many of the phenomena displayed; but, directly the question of a psychical correlate appears, all is confusion. Let us now look more closely at those forms of activity known as (1) "reflex," (2) "automatic," and (3) " voluntary," and from a study of the two former modes let us see \\'hat we are entitled to conclude in regard to the third. Reflex acts have no psychical accompaniment, they are initiated by means of external stimuli, and the motion is fairlj^ constant. The term " excito-motor " has been applied to them. Such reflexes include the ordinary physiological reflexes of organic life. Some authors describe under reflex actions all the active states which are the involuntary results of psychical 420 THE WILL. states. Harris* has attempted to classify reflex actions on a psycho-physiological basis, as follows :- I. Periphero-motor — 1. Excito-motor. 2. Algio-niotor. 3. Sensori-motor. 11. Centro-motor — 1 . Emotio-motor. 2. Ideo-motor. In this scheme the various groups of reflex actions are arranged in ascending degrees of psychological complexity. The scheme in its entirety would correspond to the sum total of the involuntary actions of life, and wei'e we unable to exercise the prerogatives of a will, our lives would be, and possibly might be explained as, mere reflex mechanisms, with a superimposed ideational state which becomes aware of what has happened to us and how we have reacted upon it. Without the element of the will we fail to differentiate between actions which are involuntary and those which are voluntary. In our acceptation of the term " reflex," it is unnecessary to wdden its meaning to include the various psychical elements of action ; otherwise we should be compelled to return to the metaphysical cjuestion as to how far all mental activity is reflex. Automatic acts have been described as evidences of mental automatism. The actions are generally appropriate, modified by some intercurrent cerebral influence, and have no equivalent in consciousness. Hack Tuke defines mental automatism as " a state in which a series of actions are performed without cerebral action or conscious will, as during reverie, or in certain morbid con- ditions." t We do not regard this definition as satisfactory, inasmuch as we look upon the phenomena as being essentiall}" forms of cerebral action. It is impossible to conceive the occurrence of many of the higher forms of automatism as being- other than the expression of the automatic action of the cerebrum. Carpenter says, •' Looking at all those automatic operations by which results are evolved without any intentional directions of the mind to them, in the light of reflex action of * " Brain," 1894, p. 232. f "Tuke's Dictionary," p. 115. AUTOMATIC ACTIOX. 121 the cerebrum, there is no more difficulty of comprehending that such reflex actions may proceed without our knowledge, so as to evolve intellectual products, when their results are transmitted to the sensorium, and are thus impressed on our consciousness, than there is in understanding that impressions may excite muscular movements through the reflex power of the spinal cord, without the necessary intervention of sensation." * We find great difficulty in satisfying ourselves upon this point. According to the theories of the day, psychical states are the concomitants of various physiological activities within the cerebrum. With the higher automatic acts we are forced to assume that these physiological activities occupy within the cerebrum the so-called sensory or motor areas ; in fact, the same nervous elements as are involved in ordinary conscious reactions. Therefore, unless we hold that the mind depends upon activities occurring at some other site or level, we must grant that the mere physiological activity of the strata which subserve consciousness — the so-called sensory and motor areas — are capable of determining a psychical correlate in some instances, and not in others. For the present we can ofifer no solution of this question. It is difficult to understand how apparently identical physiological processes may occur with such widely different psychical correlates. Voluntary acts have conscious correlates. The nature of the psychical elements involved in voluntary action we have already in part considered : it will be necessary, however, to devote some attention to the so-called " ideas of motion"' which precede the actual motion, and to the so-called " kinassthetic sensation," or " sense of effort," which follows the motion. Ziehen believes, that between an idea of the motor act to be performed and the sensation derived from the performance of the act, there is no other psychical element introduced. He reduces the psychical elements of voluntary action to ideas and sensations. He does not believe that a third psychical factor exists, unless the association of sensations and ideas be con- sidered as such. In his efforts to prove that no other psychical element is introduced, he shifts the whole responsibility of the action upon ideation, and thereby makes the individual an * " Mental Physiology," p. 607. 422 THE WILL. ideo-motor reflex mechanism. He fails to account for the conscious selection of one out of a series of ideo-motor reactions. We hold, therefore, that in the play of motives (the review of ideo-motor activities — deliberation) a choice is made by the mind as to which action is most appropriate, and with this is involved the recognition that the ego is free to judge the merits of the ideas. With the selection of the most appropriate idea, the necessary activity is called forth. Moreover, it is just this conscious selection of activitrj, and the relation of its interiJi^eta- tion to the ego, that determines the difference hetiueen the higher forms of automatism andj voluntary activity. Ziehen believes, that the feeling that we exercise a free choice in the association of ideas and in action is easily explained by the fact that, in distinction from automatic acts, association and action are not only determined by external stimuli, but are also influenced by ideas, the sum total of which we may designate as our empirical " Ego." " We believe that we exercise a free choice," says Ziehen, "because (1) we ourselves are conscious participants in the active association of ideas ; and (2) although the result of this association, or, in other words, the result of the play of motives, is not distinctly foreseen, it is nevertheless anticipated ; (3) because the decision is also finally made by a part of the ego — i.e., the prevailing ideas." This assumption, that the ideas themselves make the final decision, is incompre- hensible. We can as readil}' conceive a series of examination papers settling among themselves the question as to which should take the prize, without the decision of the examiner, as we could conceive a series of ideas determining among them- selves as to which might be the most fit to represent the organism, without reference to the ego itself. If we grant that an idea alone can determine an activity, then we must also grant that an idea can actively compare itself with other ideas. Similarly, when a fallacious conclusion is brought into consciousness side by side with a conclusion that is valid, the fallacious does not itself bow and retire on account of the merits of the valid. The decision is made by the ego itself; the logical train of thought whereby that decision is arrived at is merely the instrumental means at the disposal of the individuality which reflects and judges. Hence we take it that the arguments hitherto adduced against VOLUNTARY ACTION. 423 the existence of a will are invalid. The conception that the last witness in a trial determines the decision, and that the witness is, in fact, the jndge himself can scarcely commend itself to an3^one ; and yet this is the argument pushed forward by one of the most strenuous advocates of the non-existence of the will. Let us now consider more particularly those motor images, or ideas of movement that immediately precede the actual per- formance of a movement. A primary act is reflex or involun- tary, and the revival in memory of the image of tlie act may result in its repetition, also involuntarily. When, however, an image of movement is deliberated upon, desired, resolved, and willed, then the realisation of the act is voluntary. Some individuals — persons who possess a weak will — are subject to uncontrollable or involuntary reactions, due to the intensity or nature of the revived image. James says the first point to understand in the psychology of volition is, that " voluntary movements must be secondary, not primary, functions of our organism." He regards reflex, instinctive, and emotional movements as being primary performances. It is difficult to clearly define the transition between so-called primary perform- ances and those which are secondary. In some of the emotional movements, for instance, we are often unable to decide that there has been no revival of a former experience. In fact, we are inclined to lay more stress upon the factor of conscious deliberation and selection, than upon the mere question of the secondary nature of the movement. Undoubtedly, ideas of movement are pre-requisites of voluntary action ; but were the elements of memory entirely eliminated from an emotional movement, that movement would be wanting in its charac- teristic features and expression. We have only to observe the absence of emotional movements in some amnesic patients to satisfy ourselves that the memory is almost as important in the higher involuntar}^ as in the truly voluntary or deliberative series of events. In both instances, guiding sensations are absolutely essential for the successful performance of the series of acts. The pianist who performs automatically depends upon guiding sensations as much as the one who concentrates his attention upon his kinsesthetic impressions. In the state of artificially induced hypnosis, the will power 424 THE WILL. is sometimes retained intact. Bramwell has demonstrated that although there is an extreme readiness to react to suggestion from without, jet there still remains a higher controlling- influence, or auto-suggestion, which enables the hypnotised person to deliberate, choose, and inhibit at will. During the waking-state of one of Dr. Bramwell's patients we made the suggestion to her that she ought to resist a certain movement during her hypnotised state. Dr. Bramwell was not present at the time that the suggestion was made, and was quite unaware of the restriction imposed upon the patient. On testing the movements suggested during the hypnotic state, he found that the patient absolutely refused to carry out his sug- gestion with regard to this particular movement. The auto- suggestion proved as efficacious during the artificial state as during the normal state. How we are to explain this retention of the individuality of the subject we do not know. The facts alone would appear to warrant the conclusion that the memory image of the special act to be restrained was present during the artificial state, and that there existed a certain degree of con- tinuity between the primary mental conception and the secondary inhibition. On again awaking this patient remem- bered our suggestion, but had not the faintest recollection as to what had happened during hj^'pnosis. This c[uestion becomes one of extreme importance from a medico-legal jjoint ofview. Dr. Bramwell believes that patients in the hypnotic state almost invariably refuse to perform acts which would be criminal or even indecent. Whether the refusal is only a manifestation of an acquired tendenc)^ to resist or to act in certain directions, or whether there is some mentalisation possible apart from true consciousness, we cannot attemj)t to decide. In the present instance the refusal to perform the movement (to make her arm stiff) was evidently the result of ante-hypnotic suggestion. We have yet to learn how far an individual is truly responsible for his actions during certain mental states ; and, as the student may gather from such instances, the mere absence of memory of the events which have taken place during those states need not entirely negative the possibility of there having been some freedom of choice and the power of restraining certain actions. FEELING or EFFORT. 425 The Feeling of Effort is of great psj^chological interest, and its relation to voluntary action has been the subject of a considerable amount of discussion. Mllller * believed the nervous process to be purely central, and to consist in an efferent motor discharge. Bain, Wundt, and others adopt similar views. Most observers, however, believe that, apart from the psychical elements of deliberation, choice, resolu- tion, etc., the feeling of effort is derived from the periphery by means of afferent sensory stimuli. From what we have already said about the feeling of effort in regard to the localisa- tion of objects in space, the student will probably agree, that the theory of its central origin does not appear to be true. One fact in itself is significant, a person may retain his power of voluntary movement, but fails to obtain the feeling of effort when peripherally initiated stimuli are rendered impossible through paralysis of sensation, or after the amputation of a limb. Ludwig, Hughlings-Jackson, Crichton Browne, and others still uphold the " central " theory. Bastian, Ferrier, and others refer to the doctrine as disproved. Waller f made an objective study of the sense of effort, and svipported the theory, that nerve, in so far as it is accessible to physical examination, is pre-eminently a passive and force-transmitting organ, and not an active force-producing organ. After excluding the nerve- fibre from consideration, he attempted to prove that the sense of effort is derived from sensations with action, whilst the sense of fatigue is also derived from sensations, but with after action. " The first is a sensation accompanying muscular action ; the second is a sensation consequent upon muscular action. The first owes its being to molecular changes which accompany muscular action; the second to molecular changes which have accompanied muscular action — i.e., they have a common cause, the changes which produce the first also produce the second, and it is not material to our argument whether the positive changes with the effect are succeeded by positive or by negative after-changes, as the substratum of the after-effect." We cannot enter further into the physiological aspects of this question. What we have to decide is, Is there, in addi- * "Psychologie d. Menschen,' ii. p. 500. t "Brain," 1891, p. 181. 426 THE WILL. tion to the images of passive sensation, a feeling of a particular kind associated with an outgoing current ? Professor James has shown that the assumption of the feeling of innervation is unnecessary. To this view we conform, and we do not admit the necessity of an additional antecedent — the feeling of an efferent current — for the determination of a movement. The actual movement may be preceded by a state of consciousness made up of impressions derived from the periphery, or, possibly, reference may be made to impressions derived from a former completed circuit of afferent and efferent currents ; but the mere fact of reference being made to the results of former out- going currents, in no way implies, that before the present move- ment occurs there is a similar discharge in an outward direction. Our experience is mainly derived from ingoing stimuli, and from the secondarj' ingoing stimuli, which are determined coincidently with the effects of outgoing stimuli. Therefore, we hold that, before the performance of a voluntary move- ment, there may be a revival in consciousness of the effects of former ingoing and outgoing currents ; but that it is un- warrantable to assume, that with such a revival in consciousness, there is any actual revival of those physiological ingoing and outgoing currents themselves. The feeling of outgoing dis- charge is in reality nothing else than the feeling associated with the j)erception of the effects of an outgoing discharge — i.e.. kinaesthetic images may be the last psychic antecedents of actual movements, but those images need not necessarily be attended by actual outgoing currents. Why the feelings of innervation should be supposed to exist for movement alone, ^^'e do not know ; were the theory plausible, we ought to be able to formulate some similar doctrine in the case of the other senses, and imagine, apart from adjustment, an outgoing current from the brain to the visual apparatus, preceding the voluntary perception of an object already within focus. Professor James has pointed out in very clear terms, that we have no introspective evidence of the feeling of innervation. The only psj'chic state which introspection lets us discern as the forerunner of our voluntary acts is an anticipatory image of the sensorial consequences of a movement, |>/us (on certain occasions) the fiat that these consecjuences shall become FEELING OF EFFORT. 427 actual.* Ferrier has demonstrated, that the consciousness of effort coincides with actual muscular movements present, and that no matter how much a person wills to perform a movement, unless there is some actual movement determined by an out- going current, there can be no consciousness of effort. Miinsterbergt has also denied the existence of such a thing as a sensation of volitional energy. He gives as reasons against the theory of the feeling of innervation : (1) Our ideas of movement are all faint ideas, resembling in this the copies of sensations in memor^^ Were they feelings of the outgoing- discharge, they would be original states of consciousness, not copies, and ought by analogy to be vivid, like other original states. (2) Our tinstriped muscles yield no feelings in contract- ing, nor can they be contracted at will, differing thus in twu peculiarities from the voluntary muscles. What more natural than to suppose that the two peculiarities hang together, and that the reason why we cannot contract our intestines, for example, at will, is, because we have no memory-images of how their contraction feels ? Were the supposed innervation-feeling always the " mental cue," we do not see why we might not have it even where, as here, the contractions themselves are unfelt, and why it might not bring the contractions about. + Having satisfied ourselves that the feeling of effort or innervation is nothing more than the revival of the sensible effects of a former reaction, and that the revival anticipates a 'present movement, we pass to the consideration of some of the active motions which seem to involve a special fiat of the will. At the outset, we granted that feelings or ideas may precede actual movements, and that the existence of an idea may pre- cipitate the movement ; but we hesitated to adopt the vie^^• that all voluntary movement was simply ideo-motor — i.e., involving no other psychical elements than ideas. Professor James believes that the inhibition of a movement no more involves an express effort or command than its execu- tion does. " A waking man's behaviour is at all times the resultant of two opposing neural forces. With unimaginable * "Principles of Psychology," vol. ii. p. 501. t " Die Willenshandlung " (1888), pp. 73, 82. X Miinsterberg, op. cit., pp. 87, 88 (quoted from James). 428 TIIP] WILL. fineness some currents among the cells and fibres of his brain are playing on his motor nerves, whilst other currents, as un- imaginably fine, are playing on the first currents, damming or helping them, altering their direction or their speed. The upshot of it all is, that whilst the currents must always end by being drained off through some motor nerves, they are drained off sometimes through one set, and sometimes through another, and sometimes they keep each other in equilibrium so long that a superficial observer may think they are not drained off at all." This hypothetical explanation of what takes place within the sensorium would be more readily conceivable were we able to eliminate the psychical element from our consideration. It is difficult to imagine a conflict between phj^siological currents, irrespective of their ps3^chical correlates. We can speak of the conflict between motives, or incentives to act, from a psychical point of view ; but we cannot grant that the act is determined entirely by the result of opposing influences in currents. The student must remember, that mental conflict is a fact of ex- perience, and that the physiological equivalent is a mere con- jecture which will not bear investigation. We are no more warranted in this case to suppose that the physical activities provide the full contents of conscious volition, than we were in the case of perception to suppose that the physical apparatus provided the mind with the ready-made percept. The conflict- ing currents — if currents there be — do not " fight it out " among themselves, and provide the ego with a ready-made fiat presenta- tion— i.e., we have no data to assume that the physical process accomplishes a definite activity without the correlation of just as definite a thought or mental process. When we attempt to explain the origin of these opposing currents, we are forced to take account of various psj'chical elements ; and here, again, we become involved in difficulties, for we cannot assume that mind in itself possesses a mateuial force. Mercier concludes, that the action of nerve centres is arrested by a modification of the same process that sets the action going by the impact of an extraneous force. " The nerve-currents," says Mercier,* " are known to be undulatory in form, and the nullification of one set of waves by another similar set, is a * " The Nervous System and the Mind," p. 74. INIIIBITIOX. 429 familiar occurrence in various regions of physics. The phe- nomena of the interference of waves of light and of sound, are cases in point. One set of sound-waves may so act on another set as to result in silence. . . . Hence, if a centre is put in action by one nerve-current, it is easy to conceive, nay, it is a necessary consequence of the constitution of nervous tissue as thus far expounded, that it should be liable to be put out of action by another nerveH3xirrent." The same author has sought to prove that every part of the nervous system is at all times the seat of continuously flowing currents of force. " Along every nerve- fibre gushes of force continually succeed one another, as waves of blood pass through the arteries. Every nerve-cell is, as it were, a heart, which receives the current flowing into it, and discharges it with increased impetus."* Mercier also states that, in order to start a nerve-centre into action, some force must impinge upon the centre from a source external to itself. " A centre at rest will continue at rest, and if in action, will con- tinue to act in the same way, unless acted on by some extraneous force. Both to start the action, and to arrest it, some influence from outside the centre is necessary. The initiating impulse comes always, directl}^ or indirectly, from the periphery of the bodj", and so from the outside world." Let us now try to adapt a psychical process of inhibition to the imaginary phj'sical counterpart, and let us, if possible, understand what happens. Firstly, we are to regard the nerve- cell as a pump somewhat similar to the heart, its functions being to receive and pump currents in this and that direction. Next, we are to regard its pump action as determined from the periphery. The " gushes of force " succeed each other regu- larly in the ordinary way — i.e., when there is no particular form of movement to be performed. When, however, a special movement is to be performed, there is a special stimulus from the peripher}', a special action of the nerve-cell, and a special direction of the current to the special motor apparatus ; and, as the consequence of this peripherally initiated nerve-current, the movement is rendered effective. Inhibition is thought to arise in much the same way. A specially appointed and peripherally initiated current starts the activity of another nerve-piunji. which directs an opposing current to impede the other, and * Op. cit., p. 75, 130 THE WILL. thei'el:»y inhibit it. Mercier raises the hypothesis, that the extrinsic influence which tends to keep the nerve-cell from excessive activity is carried on by the motor centres concur- rently with their more generally recognised function. Here, then, we have two sets of peripherally initiated currents — the active, and the inhibitory — acting in succession. The former leads off from periphery to pump, thence to motor apparatus ; whilst the latter also leads off from periphery to pump, but overtakes the former, gets in front of it, as it were, turns it back, and thereby inhibits it. If the student can imagine one pulse-wave overtaking another and preventing its further flow, then he can also imagine the same with the nerve-currents. Inhibition is, psychologically and physiologically, a positive activity ; and just as it is impossible to obliterate a recent thought by a present one, so it is impossible to interfere with one current by the passage of another. Each event is distinct and separate. With the assumption that there is a special inhibitory apparatus for the control of the force of the nerve- currents, we have nothing to do. We are prepared to admit that the nervous apparatus itself has a regulated tone. At the same time, however, we confess that we do not understand either the physiological nature of the tone or of the activities regulated by it. The term " nervous resistance " is freely employed b}^ some authors to indicate a hypothetical physiological state. Mercier says, " It seems reasonable to suppose that just as the physical process of the nervous discharge, when \aewed in the aggregate as a physiological process, is the motor of muscular movement ; so the nervous resistance when raised to the same power is the phjT'siological factor inhibition." Let the student analyse the nature of events during an act of inhibition. In the first instance we must presuppose a tendency to act in a certain direction, and we may assume that there is a corresponding nervous activity ; next there comes the inhibitor}^ act with its nervous equivalent. We ask. In what wa}^ does the second activity differ from the first? In both series of events the activities are positive. I forcibl}' exaggerate my knee-jerk, or I inhibit it. Wherein is the difference ? We can resist the effects of a just past nervous activity by the exertion of a NERVOUS RESISTANCE. 431 present positive activity ; but we cannot set up two currents in opposition to each other. When we look at an acutely maniacal patient we note his varied and often purposeless movements ; and, moreover, such patients, on recovery, will sometimes say of themselves that they also had noted the motor excitement, but had insufficient power to control it. In such instances the nervous apparatus has been unduly active, and the individual has been deficient in the strength to control action. Mercier's conception that every nerve-centre is at all times subject to continuous control or inhibition, appears to be perfectly feasible, and we must accept the hypothesis that the nerve-centres are maintained in a condition of mobile equilibrium by the oppo- sition of the inhibition exercised upon them, to their own inherent tendency to discharge, as manifestly true, inasmuch as it would be ridiculous to imagine any physical or systemic activities without such controlling influences. We do not, however, go so far as to imagine that the state of inhibition is maintained by centres which exercise this function concurrently with others. The student must not confuse the notion of mere mechanical obstruction Avith that of so-called nervous resistance. The former may exist as a patho- logical factor of great significance in the causation of morbid mental states ; whilst the latter may exist as a law of physics, of which, however, we do not as yet grasp the full psychological significance. To put the matter shortly, we may sa}', that (1) the regulation of the activities of the nervous system is determined by physiological laws, which, by analogy, appear to warrant an hypothesis about "discharge" and "resistance"; (2) when a psychical element is involved, the inhibition of one act is only possible by the positive exertion of another act \\-hich overcomes or negatives the effects of the first act ; (3) the tendency to excessive activity of the nervous elements may be checked by the exertion of controlling nervous influences apart fi'om any psychical influence, in which case the inhibitory influence may be termed physiological ; but this physiological inhibition does not necessarily imply the existence of an opposing current which checks the positive current by an intra-tubular conflict ; (4) the tendency to excessive activity of the nervous elements may, by the involving of psychic influ- 432 THE WILL. ences. be controlled by the positive exertion of other activities which overcome or render inert the effects of the excessive nervous activities. Thus, we are warranted in steering clear between' the incomplete conceptions of physiological and psychological inhibition. Movements. — Mercier has classified movements according to their character and to the parts of the body concerned with them. He clearly points out the difference between central and jjeripheral movements in regard to their precision, number and variety, generality and speciality, simplicity and complexity. Generally speaking, peripheral are more precise, more numerous, more varied, more special, and more complex than central movements. The co-ordination of movements may be simvHa- neons or sequential — i.e., one movement may l)e combined with another movement simultaneously, or one movement may follow upon another movement as a sequence. " Those movements which are combined (co-ordinated) in simultaneity being mainly central, while those which are co-ordinated in succes- sion are predominantly peripheral." The movements of the more central parts serve as a basis for many peripheral move- ments. The human body is capable of carrying on several series of central and peripheral movements at the same time. Thus, the organist may co-ordinate the movements of simul- taneity and secjuence of his legs, as in the act of pedalling ; he may co-ordinate a similar series of movements of his arms in the act of fingering the key-boards and stops ; he may also read the score before him, and co-ordinate the movements of speech and song ; and moreover, in addition to all this complex activity, he may be conscious of totally irrelevant matters. In the insane we see every variety of movement in simultaneit}' and succession. Thus some idiots and imbe- ciles constantly sway to and fro ; others incessantly move their fingers or toes in a rhythmical manner. The flocci- tatlo of the comatose, the rocking movements of the agitated melancholiac. the picking movements of the general para- lytic, the constant restlessness of the maniac, the move- ments of the fingers in chorea, and the convulsions of the epileptic are all capable of classification. Space, how- ever, will not ])ermit us to consider all those variations of MOVEMENTS. 433 movements that depend primarilj^ upon diseases of bones, liga- ments, mnscles, tendons, or upon affections of the motor nerves ; nor can we discuss the influence of lesions of the sensory nerves, or the reflex mechanism of the spinal cord in the production of disorders of co-ordination. From a clinical point of view it is of interest to note, that cerebellar lesions determine movements which spread centrifugally, while cerebral lesions usually determine movements which extend from the periphery to the more central regions. Before entering upon the question of abnormal conduct, and the habits and limits of self-control, it is necessary that we should devote some attention to the physiological processes connected with the production of speech. The motor pro- cesses, so far as they affect the larynx, pharynx, mouth, and nose, in the production of musical tones and noises, do not concern us. Presently we shall take some account of the pathological variations of the voice and speech ; for the present we have only to do with the psychical and phj^sical processes involved. We have already considered the question of the locali- sation of the centre for speech, and we have taken some account of the motor tract, and the effects of its lesions upon the mechanism of articulation, so that it is unnecessary to revert to them. By far the most important mechanism of expression possessed by the human being is that of speech. By the move- ments of articulation we give expression not only to our sensa- tions and special emotions, but also to ideas derived from memory and innumerable associations. When the region of Yv^ernicke. in the auditory centre in the left temporo-sphenoidal lobe, is destroyed, words are still heard but not understood.* In studying the mode of expression in speech it is important to note the anatomical localisation of the tracts which have to do with expressive and imitative movements. Bechterewf and Ziehen j found that after the entire cortex of the cerebrum had been removed from a rabbit it still performed its characteristic * Ziehen, op. cit., p. 260 ; Wernicke, "Der Aphasische Symptomen-com- plex," Breslau, 1874 ; and in Friedlander's " Fortscliritten der Medicin," 1886; Grashey, " Archiv. f. Psychiatrie," 1885; Lichtheim, " Deutsch. Arch, f. Klin. Med.," Bd. xxxvi. + " Virchow's Arch.," Bd. ci. J "Archiv. f. Psych.," XX. 28 434 THE WILL. movements of expression, such as bobbing the tail. Nothnagel* believes, that the centre for the mimic expressive movements is located in man in the thalamus opticus, whereas the centre for the most complicated expressive movements is located in the cortex cerebri, the nerve-tract being chiefly in the pyramidal, tract. The tract between the thalamus and the cortex, which would provide the psychical factor, is not as yet determined. Ziehen! believes, that certain expressive movements, such as the bristling of the hair, blushing, etc., probably have their centres in still deeper parts of the brain, particularly in the medulla oblongata. This, he says, harmonises with the fact, that these expressive movements also result from psychical causes, but are virtually not subject to the volition, or, more properly, to the process of association at all ; they cannot even be voluntarily suppressed. Of the various forms of aphasia we have already spoken. Undoubtedly, it is to the study of such conditions as word- blindness (alexia, coccitas verhalis) and word-deafness (surditas verhalis) that we are to look for some clue as to the localisation of events revivable in memory. In word-deafness the patient does not hear words, but hears other sounds, and is not deaf. In word-blindness there is inability to understand printed or written words, or familiar objects, although he can see quite well. Lichtheim has pointed out, that the " auditory word- representations" form the starting point of language. Auditory images and motor images must be combined in order that an imitation of a sound may be produced. The physical equivalents of ideas of articulation are sup- posed to rest in the posterior inferior part of the frontal con- volution. When this part of the brain is destroj^ed the power of moving the apparatus of speech is retained, but the individual is unable to articulate anj?" word. For the com- plete utterance of articulate language it is essential that this latter region should be intact. Similarly, as we have seen in a previous chapter, it is essential that the regions for acoustic and visual images should also be working normally. In the case of visual images both hemispheres of the brain are * "Zeitschr. f. Klin. Med.," 1889, Bd. xvi. H. 5 and 6. t " Sphygmograph. Untersuchungen," 1887. MECHANISM OF SPEECH. 435 involved, whereas the images of articiilation and hearing appear to be deposited in one hemisphere only (in the left hemisphere in right-handed persons). For the complete conception in con- sciousness and the due utterance of articulate language, there- fore, it is essential that the regions concerned with the repro- duction of the images, both sensory and motor, should be intact, and that the tracts of communication with the higher perceptive centres should also be normal. It is hardly necessaiy to return to the question as to how the component parts of the idea of words become associated as a general concrete conception. We know so little about the formation of simple perceptions from a ph3'siological point of view, that we naturally hesitate to attempt to explain the formation of a general concrete conception such as is involved in articulate language. The view of Hughlings- Jackson, that words are revived, in silent thought, as faint articulatory processes taking place in motor centres, need not l)e discussed, inasmuch as it would only involve a repetition of the arguments against the existence of actual outgoing currents, or feelings of innervation. The fact, that some people read aloud, or give articulate expression to their thoughts, is obviousl}^ no evidence in favour of the theory. We agree with Bastian, who believes, that there are good reasons for rejecting the notion, and that the materials of our recollection, in the idea of words during silent thought, are revived articulatory sensations. The arguments we have given as to the nature of ordinary revived kingesthetic sensations apply equally \^■ell to actiTal speech. We are aware of the importance to be attached to the joint operation of the auditory and visual apparatiises in the development and production of speech, and we fully appre- ciate the fact, that total deafness supervening in a child in full possession of speech, as late as the fourth, fifth, or even the sixth jeav, will entail dumbness ; but that a revival of the auditory impression is not essential to acquired articulatory speech is evidenced by the fact, that the auditory word-centre may be affected without any impairment of articulation.* * Bastian, however, does not attach too much importance to the auditoiy impressions in the production of articulate speech ; his remarks apply rather to the revived imasfes of silent thought. 436 THE WILL. Before leaving this part of our subject it is essential that we should speak briefly of some of the clinical disorders of the kinassthetic word-apparatus. We have already discussed the auditor}' and visual word-apparatuses and their aberrations of external and internal origin, and when we take into account the lowered or excessive activity of them as associated even ^^ith various states of health, and also include the possibilities of their iDeing affected by the excitability of the perceptive centres supposed to exist elsewhere, we can more readily understand how morbid presentations and representations arise in the insane. Speech movements and writing movements may be affected secondarily through lesions of the auditory or visual woi-d- centres of the associative or thought-processes, or through lesions of the kin^esthetic word-centres, which serve to transmit the impressions derived from the active expression of our thoughts by speech or writing. Clinically, we have to note — (1) deaf-mutism as the result of congenital disease. Idiots may never acquire the power of speech. In some cases this is the result of disease before or after birth ; in others it is merely the result of deafness. Many idiots only acquire the po^^'er about the fifth or sixth year ; others have acquired the power, but lost it again owing to deafness, supervening. It is common to meet with idiots who can hum tunes, but who cannot repeat words. The auditory apparatus may be cjuite normal, and there may even be a certain amount of musical taste in idiots ; but there is not a parallel develop- ment of the vocal articulatory apparatus. Ireland observes that, in idiocy the gift of speech bears a pretty well-marked relation to the number and complexity of ideas. He describes a certain class of "idiotic aphasiacs" who remain obstinately mute, although thev have more intelligence than other children who talk volubly. In spite of the fact, however, that they are often able to hear and to understand speech, these cases do not make much progress. In some cases the defect is attributed to a want of power over the muscles of the tongue. Sir W. Wilde* has pointed out. that in many instances of defective articulation. * '• Aural Surifery and Diseases of the Ear,'" London, 1853, pj). 46.'i-7. Irt'land, op. fit., ]ip. '274-6. SPEECH DEFECTS. 437 as well as severe stuttering and of partial mutism, there is a peculiar narrowness and an unnatural height of the palate immediately behind the upper incisor teeth. As a rule, idiots cut their sentences verj^ short : sometimes the}^ confine their remarks to monosyllables. Another characteristic feature of their speech is that, when asked a question they repeat the question several times before they recognise its import and attempt to reply. (2) Ao/uired defects of speech may supervene at any period of life. Lesions of those parts of the brain con- nected with the associative apparatus of thought may so alter the intelligence as to render speech defective ; or the defect may lie in the articulatory apparatus (the kinesthetic word- centre, as well as the mere motor tract). Stuttering and stammering are usuall}^ the results of defective co-ordination of the articulatory movements. Aphemia is generally the result of defective movement alone. It is common in glosso-larj^ngeal paralysis and other diseases of the medulla oblongata ; it may also occur in association with paralysis from cerebral disease, general paralysis of the insane, disseminated cerebro-spinal paralysis, and hemiplegia, either cerebral or pontine. A lesion of one of the oro-lingual centres of Ferrier causes oro-lingual hemiparesis, which is characterised by slight unilateral weak- ness, and not by complete paralysis. When the lesion is on the left side of the cerebrum speechlessness results. The effects of lesions in the island of Eeil, and the not uncommon associa- tion of aphasia with heminansesthesia of the right side of the body, are subjects of great import, but we cannot discuss them here. In the insane we have to note the following varieties of speech : — (1) The slow and often difficult way of speaking in melancholiacs, and sometimes also in the feeble minded ; (2) the incessant and rapid talking of maniacs and general para- lytics (logorrJuea) ; (3) alliteratioii (Mendel), the derangement in which words are not placed according to their meaning, but according to their sound; (4) verhujeration, in which there is monotonous utterance of incessantly repeated words (Kahlbaum), the W'ords being in some cases forcibly enunciated in an ex- tremely strained manner, and with evident difficulty (Neisser) ; * * " Tuke's Dictionary," p. 1355. 438 THE WILL. (5) Keisser descrilies rnntism as being an important symptom in katatonia. The patient remains silent for months or even years ; there may be a desire to speak, but inability to do so. Verbigeration not infrequently supervenes upon this mutism. (6) AJcataphn^la is the term applied to that form of sj^eech in A\'hich the individual speaks of himself in the third person, common in Scotchmen, and in idiots ; (7) mutism in the insane may be due to deaf and dumbness, absence of ideas, or the presence of delusions. Such delusions may be hallu- cinatory in origin, and in the form of a special mandate to maintain silence ; or they may be hypochondriacal with a fear of the consequences of speech. Clinically, we have to note also, that speech defects occur : (1) As spasmodic stuttering or stammering in childhood, either as a temporary or permanent defect. Bristowe regards such defects as diie mainly to imperfect training, to bad habits or slovenliness, or to some defect in the relations between the ear and the organs of articulation. When it arises in adult life, he attributes it to an attack of fever or other acute disease, to hysteria or some other nervous disorder, to nervousness or excitement, or even to temporary soreness of the tongue or lips, or other parts engaged in articulation. Among other defects of speech due to bad habits, or imperfect education, he enumerates, the habits of interpolating such expressions as " You know," " I mean," etc. (2) As a character- istic tremulousness or stammering in alcoholism. This con- dition closely simulates the speech of general paralj'sis, but there is difficulty and embarrassment rather than true ataxy. Tuczek has described the occurrence of grandiose ideas with motor and speech derangements in ergotism, simulating cases of general paralysis. Toxic agents such as quinine, chloral, atropine, iodoform, etc., have been described as giving rise to speech perversions, either increased volubility, incoherency, or embarrassment. Atropine sometimes causes difficulty of articu- lation. ^\hilst iodoform has caused actual aphasia (Legrain). (3) Speech-changes following enteric fever have been desci'ibed by Colin ^I. Campbell, who found a distinct impairment of speech co-ordination during excitement and fatigue, and, tliat this state continued for some months after the fever. Mickle has SPEECH DEFECTS. 439 also described certain post-febrile speech defects which simu- lated those of general paralysis. A slow speech with deliberate drawling, and articulation of the syllables in a monotonous tone, and ^^'ith a nasal twang, has been noted by the author as follow- ing typhoid.* Westphal noted after typhus the scanned, nasal, and monotonous speech, in which the letters and syllables were not displaced, but separated by intervals and uttered jerkily, or with visible efforts, yet, as after typhoid, without co-existing tremblings of the lips and face. (4) The dyslogic and articula- tory defects met with in general paralysis are characteristic, but space will not permit us to describe them here.f As a rule, the presence of tremors of the lips, and the characteristic dra^\'L serve to distinguish the speech of the general paralytic from that of patients suffering from disseminated sclerosis. Cases of bulbar paralysis exhibit speech defects very similar to those of general paralysis, and often by themselves difficult to diagnose. (5) The photisms of the sounds of speech have alreadj- been considered. It is interesting to note further, however, that vowel sounds are more apt to give rise to photisms than con- sonants. Photisms for entire A\'ords have been described by Bleuler and others. The readiness with which photisms and phonisms are produced is suggestive of a possible explanation of several forms of sensory perversion in the insane, and assuredly, in the not very far future, we shall have some more definite account of the relationship between the activities of the special senses and the kinesthetic impressions. (6) Aphasia may occur as a transient condition in association with the hemiplegia of children. Such transient alterations of speech have been noted in hereditary syphilis, and in one case re- corded by Barlow and Burj'j: there was thought to be endo- arteritis of symmetrical branches of the middle cerebral arteries and degeneration of the cortical centres, especially of the third frontal of both sides. (7) Special affections of speech, either of a temporary character immediately following an attack of sunstroke, or as a continued impairment or failure in development of the faculty, have been described by the "^ "Takes Dictionary,"' p. 986. t See Mickle, "Take's Dictionary" — "General Paralysis." X " Tuke's Dictionary','' i). 1265. 440 THE WILL. author.* The somatic sequelfe of sunstroke may inchide tongue tremors, and thickness or slurring of speech very similar to those in general paralysis. (8) In sleep and its associated conditions, a person inay speak and sing in a perfectly automatic way without involving an element of waking consciousness. Owing to the kindness of Dr. Bram- Avell, the author was able to witness the artificial production of every variety of amnesia and aphasia in a hypnotised person. The suggestions were made during hypnosis, and the effects were manifested during the post-hypnotic state when the patient was only imperfectly roused. Conduct. — We have seen how voluntary movement is related to impulsixe movement, and we have come to the con- clusion, that voluntary movements of the body imply a consider- able development of the mental activities of ideation and volition ; but we do not know the physical basis of volition. We may, with the advance of our knowledge of the localisation of cerebral function, arrive at some more definite conclusions as to the structures concerned with the carrying out of an act of volition, but we are not so hopeful with regard to our prospects of ever knowing what molecular changes are correlated with the psychical elements. The theories hitherto given as to the nature of the will — those explanations which have sought to show that voluntary motions follow upon certain ideas or excited states of feeling, without a conscious fiat of the will — serve to illustrate the nature of truly impulsive actions. If we regard such actions as voluntarj^, we find ourselves in the diffi- cultj^ of having to differentiate psj^chologically between such activities and those which involve an element of conscious choice. We do not know what happens in the brain when the fiat of will issues in consciousness. • The phenomenon is some- thing above, or in addition to, mere forced attention, and it is unwarrantable to assume that the fiat is a purely mechanical state dependent upon the influence of mechanical stimuli. A complete study of conduct would involve the consideration of the various forms of action and resistance, together with the psychical elements known as the motifs and jiats, or, in other words, the whole of the physical and psychical factors which * " Sunstroke " — " Takes Dictionary," p. 1234. CONDUCT. 441 serve to bring about the adjustment of the organism to its environment. The physiological methods by which internal processes of the organism are adjusted to one another, and by which movements are brought about, are little known to us. The psychical methods, on the other hand, by which the organism is consciously adjusted as a whole to its environment, are more easily demonstrated. The nervous mechanism of conduct has already been con- sidered, and we have tried to understand the nature of the pro- cesses in the highest nervous centres, by which the acts of the organism are adjusted to external circumstances. We may say, briefi}^ that the appropriateness of individual conduct depends upon (1) the proper working of an educated reflex or automatic mechanism; and (2) the proper physiological and psychological adaptation of the nervous sj^stem and the mind to the environ- ment. Mercier says of a reflex act, "It is an act that was once intelligent, that was once preceded by deliberation, by choice, and by will, but that in the course of innumerable repetitions in the lifetime of many generations has become first habitual, then automatic, and finally reflex ; and to this end all our acts are tending." '* In another place he says, " If there is any- thing certain in life it Avould appear to be that we move our limbs and speak our thoughts by an effort of will, and that in this case, undoubtedly, the mental process is not only the fore- runner, but the actual cause of the bodily movement. It is not so, however The exercise of the will, which appears to be the cause of bodily movements is, in reality, the mental shado^^' of the particular nervous process which really is the cause." t In the first quotation, deliberation, choice, and will are regarded as essential to the development of reflex action. In the second, however, these factors are regarded as the effects, or " mental shadows," of nervous activities. In yet another place he speaks of the intensification of nascent activities, " all of which are striving, as it were, to become actual and to produce movement At length, owing to the nature of the im- pression, and to the direction of paths previously traversed by * "The Nervous System and the Mind,'' p. 166. t " Sanity and Insanity,"' pp. 53, 54. 442 THE AVILL. currents in circumstances somewhat similar, one of these struggling centres gains the preponderance. The fittest sur- vives. The tension among the bursting centres is relieved bj' the discharge of one of them, and thus the nervous accompani- ment of volition is not merely a discharge of a single centre, but a discharge which follows a struggle for preponderance, and marks the triumph of one of the conilicting factors. Hence, this feeling arises not only when actual movement follows this successful struggle, but arises also in a somewhat modified form when a similar struggle takes place on a higher plane of nervous action, and terminates in the preponderance of one of the struggling activities, without that activity finding imme- diate expression. In other words, volition or willing comes to be the feeling which accompanies the termination of a struggle among nascent activities b}^ the preponderance of one, just as hesitation is the feeling that corresponds with the duration of the struggle." Here we leave this discussion, in the hope that the struggle for preponderance of these conflicting statements may awaken among the nascent activities of the student a tendency to react in the right direction. That one or other of these factors will be successful ^^'e do not doubt ; we only trust that the right nascent activity may be intensified, that is, if he is to be denied the freedom of choice. Much of the confusion about the actual mental state that precedes voluntary acts arises from the fact, that an insufficient distinction is made between the guiding and instigating effects of kinassthetic impressions. Kina^sthetic impressions are guides only ; they do not instigate movements. In the exercise of voluntary movements the conscious accompaniments are epiphe- nomena, and there is every grade of mental accompaniment, ranging from so-called ideo-motor 'to true voluntarj^ activity. According to Ladd, voluntary movement implies (1) the posses- sion of an educated reflex-motor mechanism, under the control of those higher cerebral centres ^^•hich are most immediately- connected with the phenomena of consciousness ; (2j certain motifs in the form of conscious feelings that have a tone of pleasure or pain, and so impel the mind to secure such bodily conditions as will continue or increase the one, and discontinue or diminish the other ; (8) ideas of motions and positions of CONDUCT. 443 the bodily members, which previous experience has taught us. answer more or less perfectlj^to the motifs of conscious feeling; (4) a conscious fiat of the will, settling the question, as it were, which of these ideas shall be realised in the motions achieved and positions attained by these members ; (5) a central nervous mechanism, which serves as the organ of relation between this act of will and the discharge of the requisite motor impulses along their nerve-tracts to the groups of muscles peripherally situated. In our estimation of conduct we must distinguish between - acts and their effects. Sane individuals are liable to faulty and inaccurate psychological adaptations of the organism to the environment ; hence, imperfection of movement or fallacious reasoning is not necessarily an evidence of insanit3\ In everj- asylum patients are to be seen whose ordinary conduct is con- ventional in the extreme : moreover, they may possess a degree of intelligence and will-power superior to the sane, yet who are unable to manage themselves or their affairs. We have ob- served dements and even general paralytics rally after a period of apparent mental dissolution and converse rationally for a time, \\-ithout exhibiting a trace of their recent insanity. In the wards of an as3dum we see every variety of conduct, and witness the extreme limits of control, as well as of abandonment. If the student will refer to the following chapters which deal with the factors of the insanities, and build upon them the knowledge he has acquired of the development of morbid mental states, and then apply the rule, that exercise strengthens function, he will be able to recognise how a given set of circumstances arouses by its impress on the organism the same reaction that it has previously roused. Further, b}' applying the law of the " survival of the fittest," not only to stimuli, but also to their effects, he will be better able to understand how successful acts tend to be repeated, and un- successful acts to be suppressed. Among the insane, the novel and often amusing combinations of actions are explained as the adaptation of old ways of meeting some circumstances, to circumstances of a totally different nature. The conduct of the insane is usually determined either by the co-operation or the opposition of impulses. The existence 444 THE WILL. and co-operation of motives derived through some ideational or emotional derangement will often determine and further a special line of conduct. Coni3icting impulses, on the other hand, may cause a cessation of activity, and even a temporary paralysis of volition. We have already spoken of the effects of doiTbts, deterrents, and the rivalry of impulses in their relations to simple and complex actions, so that it only remains for us now to give some account of the state known as self-control. The will is able to check action or impulse by the voluntary exertion of an inhibitory or contra-action. The action which, in the natural course of events, would follo^^■ upon a motor idea can be inhibited by the will, by the exertion of another positive activity which checks the ideo-motor activity. Defect in this controlling influence renders an individual liable to become a passive participator in impulses which range from mere rashness to homicide. An individual with imperfect control is apt to act on the spur of the moment, and to respond to every stimulus from Avithout. In acute mania, active im- pulses, inability to inhibit sensory stimuli, and almost constant restlessness, are characteristic symptoms. In these instances there is loss of the higher order of development of the faculty of control— i.e., there is no subordination of the particular and temporary ends to the general and permanent interests. Control of the feelings is often a much more difficult matter. There are times when it is well-nigh impossible to control our emotional reactions. Undoubtedly, however, it is among the insane that the feelings are wont to play the greatest pranks. Emotions literally take possession of our muscular system, so that a greater expenditure of energj^ is necessary in order to overcome their effects ; and, moreover, the intensity of the emotion tends to weaken the force of the will from the psychical side. Perfect control of thought presupposes not only the faculty of attention, or fixation, or focussing representations before the mind, but also perfect control of feeling. Ferrier says the internal diffusion of nerve-energy involved in thought, and the external diffusion of it in muscular action, vary in an inverse ratio ; consequently, in the deepest attention, every movement which would diminish internal diffusion is likewise inhibited. LOSS OF CONTROL. Ub- Plence, in deep thought, even automatic actions are inhibited, and a man who becomes deep in thought while he walks may be observed to stand still. Mercier objects to the expression " loss of control," and seeks to reduce what we accept as a fact of psychological significance to its equivalent in molecular physics. This physical equivalent he finds in the stability of a mobile equilibrium of atoms. Reference might with advantage- be made bv the student to the cjuotation on p. 147, in which the same author demonstrates that similar hypotheses are, to use his own expression, '• nonsense." The amount of force which can be overcome by an effort of the will is the test whereby the strength of the will is measured. Some individuals are unable to resist forcible stimuli coming either directly from without, or indirectly by the association of ideas. An increase of the force to be overcome, or an impair- ment of the po\\'er of overcoming that force, may determine loss, of control. This is well sho\vn by Ribot in respect both of the loss of control over impulse, and of the impairment of control of the attention and the flow of ideas. In mental diseases there may be loss of self-control in a psychical sense, or defective inhibition in a physiological sense (as, e.;/., in im- pulsive insanity, and maniacal states) ; or, on the other hand, there may be defecti\e energisation or loss of power of exciting-^ activity (as in stupor, melancholia, etc.). Clouston puts it clearly when he says. '• The driver may be so weak that he cannot control well-broken horses, or the horses may be so hard-mouthed that no driver can pull them up." In some cases. it is difficult to say where the defect lies. Clouston states, that in the young "there is absolutely no such brain-power existent as mental inhibition ; no desire or tendency is stopped by mental act." Later, he says, " The power of control is just as gradual a development as the motions of the hands." With the latter statement we agree, and, in conformity with the fashionable phraseology of the day, we may posit the rudiments of mental inhibition as a " nascent state " with the first act of life. The processes of experience of the physical activities are parallel with those of the mental. There is no jDcriod in the life historj- of an individual when physical or mental inhibition can be said to develop as a. 446 THE WILL. siiperniimeraiy factor. The parallelism miist be complete from the beginning; the "nascence" of one must coexist Avith the " nascence " of the other. When dealing with the minds of idiots and imbeciles, however, we are scarcely warranted in assuming that their mental defects may be only nascent potentialities of the powers of a Mozart, Darwin, or Spencer. In mental disease loss of self-control is often a characteristic symptom. The loss of power of inhibition, viewed physiolo- gically, may be due to causes which interfere with the due regulation of the physical activities ; and in dealing with such modes of activity, we have to take account not only of the molecular physics and the possibilities of decomposition of unstable matter, but also the special molecular physiology which M^ould correspond to what we term " life." The loss of power, \Adien viewed psychologically, however, involves the consideration, not only of the phenomena of physics and life, but also of the epiphenomenon of mind. As we have already seen, it is utterly impossible to explain life by the mere enumeration of its physical manifestations, and it is just as impossible to explain mind by the enumeration of the mani- festations of life. We cannot explain the ivill hif the mere enu- meration of the contents of consciousness i^recedinrj the actual performance of a voluntary inovement. So long as we view self-control from a purely physiological point of view, we must of necessity view the mind as a mere passive spectator of the conflicting activities going on within the organism. Mercier asks us to try to imagine the idea of a beefsteak binding Uvo molecules together. Of course, it is impossible. We only ask in return, try to imagine two molecules binding themselves together so as to produce an idea of a beefsteak. Simply because there is no community in nature between the two series of events, such a conception is regarded as unimaginable ; and yet we are told almost at every turn that the phj^sical series can regulate its oaa'u activities, but that the mental cannot do so. Here, again, unless we develop a disposition to materialism, we must grant that the parallelism between the brain and mind series of events is complete ; otherwise we decide arbitrarily that the activity of the inevitable molecule is CONCLUSIONS. 447 the cause and not the concomitant of the psychical event. The tendency of most writers npon this vexed Cjuestion is, to dis- continue the parallelism after they have reached a certain stage in their inc[uiries. IMercier appears to regard the exercise of the will as nierelj^ " the mental shadow of the particular nervous process which really is the cause " ; thus making the nervous structure the guiding and controlling mechanism, the mental ecpiivalent being only a shadow of what takes place. The relationship of the molecule to its mental shadow is particularly susceptible to speculation, and it is only reasonable to assume, that the mental shadow may, in its turn, be a motor or inhibitory one. In fact, an inhibitory mental shadow is a necessary correlate of a physical inhibition. That one factor is essential to the existence of the other, we believe ; but we have no more authority to state that a material action can throw an immaterial shadow, than we have to state that an immaterial action can throw a material shadow. Both are shadows, so far as we are concerned, and we do not understand their nature. For an account of the so-called "fulminating psychoses," or states of defective inhibition, the student is referred to the various text books on insanity. It is in the insane that we meet with the most marked evidences of the existence of a will ^^dlich may become violently affected or rendered altogether inert. That this is coincidental with, some impaired vitality, we do not deny ; we merely stop short at the arbitrary decision that the manifestations of what we conveniently term the " will" possess any causal efficacy. Let us now briefly sum up what we can, with perfect fairness, assume as to the existence of a will. (1) There are no grounds to assume that a will exists /or us independent of physical or physiological activities. Matter, life, and mind are for us empirical correlative states, developed in a parallel series, and capable of manifesting their existence by activities, which are respectively equally complex. Any attempt at explanation of the one in terms of the other results only in confusion, or in an implied causal influence. (2) The fact, that the point to which the will is directly applied is ah\ays an idea, is no proof that the idea always determines the application of the will. The 448 THE WILL. idea itself is the mental equivalent of the instrumental means whereb}' the fiat becomes realised. Were this otherwise, the responsibility of remembering, comparing, and determining action would rest upon an idea. The struggle for survival among ideas is not one in which one idea has summed up the perfections or imperfections of other ideas, and has decided that its action is the one best fitted for the conservation of the organism. It does not, without the word of command, ride astride its material basis of " stable mobile equilibrium of atoms," and merely inform the ego of what it is doing. That the idea immediately precedes the action, we believe ; but that it causes the action is another matter. The ideas are the elements in consciousness from which the e;/o derives its knoAvledge of conflicting influences. It would be difficult to demonstrate, that ideas themselves possess the faculty of comparing them- selves with other ideas, or that the continuity of a life experi- ence is only an integral part of an idea. Here again we repeat, that just as in the leading principles in modern natural philosophy the terms attraction, gravitation, cohesion, etc., are used to represent the various manifestations of material move- ments, and just as the terms currents, mobile equilibrium of of atoms, inhibition, etc., are used to represent physiological manifestations of what we symbolise as life, so the' terms intel- lection, emotion, and volition are used to represent ps^^chical manifestations of what ^\^e symbolise as the individuality, or the eqo. (3) The outcome of the contentions is one of vast importance both to speculative theology and to science. On one point we are perfectly clear. The all-pervading condition of ignorance by which we are surrounded, most effectuall}^ prevents us from giving vent to one-sided dogmas, either in the cause of materialism or spiritualism. We can only contemplate the phenomena of matter, life, and mind as they exist for us, and avoid being blinded in our view by molecular dust or the film of fantasy. In concluding this chapter we may note that Impairment of the will may manifest itself as a condition of irresohition. This may be due to (1) weakness of motives or incitements ; (2) various states of doubt as to the nature or result of the action to be performed ; (3) excessive number of ideas, which DISEASES OF THE WILL. 449 tend to delay and counterbalance the impulsion to act in a definite direction. Ribot* divides diseases of the will into two principal classes, according as the will is impaired or abolished. Impairment of the will may be due (1) to lack of impiilse, or (2) to excess of impulse. Guislain,t Griesinger, :j: Leubuscher, § Esquirol, Carpenter,! Ribot, 1[ and Billed** have made observations upon the first group. When a patient is able " to will '' to act, or when the desire is present, but the impulsion to carr}^ out the act is absent, the condition is known as ahoulia. One patient, formerly an inmate of Bethlem, used to lament this inability to act. She was able to understand and reason upon her ordinary experiences without any observable impairment of intelligence. She was, however, unable to put into effect the result of her (ieliberations, and the desire to react to circumstances proved ineffective. Not uncommonly, such patients believe that their will is taken possession of by others, or that their actions are inhibited by some mysterious influence. Ribot believes, that the muscular sj^stem and the organs of movement remain intact; they offer no impediment. The automatic activity \A'hich con- stitutes the ordinary routine of life persists. The difficulty appears to be in passing from the consciousness of a desired end to the action, which would presumably acquire that end. The cause of this impotence of will is at present a matter of considerable doubt. Some authors maintain, that the affection is mainly due to impairment of the motor centres in the brain, and that it is the motor apparatus which is at fault. This theory, however, is generally held to be unsatisfactory. Certain it is, that patients affected with ahoulia are not necessarily deficient in guiding sensations or ideas of the movements which they are unable to perform. Ribot maintains, that there is principally an impairment of the incitements to action. * " Diseases of the Will," chap. ii. t " Legons Orales sur les Phrmopithies," vol. i. p. 479. t " Traite des Maladies Mentales," p. 46. § " Zeitschrift f iir Psychiatrie," 1847. Ii " Mental Physiology," p. 385. IT Op. cit. chap. ii. ** " Annales Mi'dico-Psychologiques," vol. X. '29 450 THE WILL. The cr)nditioii may n<:.t be due to weakness of the desire to act, Ijiit we do not concur with Ribot, that the aboulia invariably res^ilts from the absence of the states of feeling and sentiment which normalh^ accompany every sensation and idea. In some cases of aboulia — especially in melancholia and stupor — there is a comjaarative insensibility^ or even absence of the general sensibilit}' ; but again, in other cases, patients have been not only morbidly desirous of performing certain actions, but even liighly sensitive and morbidly susceptible to the emotional accompaniments of ordinary sensations. The performance of the actual action itself is purely physio- logical, brit the perception of sensations and their accompani- ments is psj'chical. We can hardly suj^pose that a pure state of consciousness is of itself capable of producing action or prohibiting it ; but, were we to eliminate the various mentj|l states which we symbolise as "will," the complicated adaptive, delayed, and purposive actions performed by the human being would be nothing short of miraculous. In fact, to A^'hatever extent the physiological theory of will be urged, it must always fail to give an explanation of those empirical psychical factors which we denominate as the will. The sense of fear acts as a deterrent of action. In such cases the incitement to act is not necessarilj^ absent. The power of readinrj to circumstances seems, however, to be entirely lost. Often there is no cause for the fear, but the motor apparatus is vhrowu completely out of gear for a time.'^ Afjoraphohia, for example, is a condition of anxiety which, as previoiisly men- tioned, renders a person powerless when he sees an open space. A condition similar in its effects to that of fear is sometimes witnessed among troops of men on active military service, and more partici;larly during the course of a fatiguing march. Suddenly, and Avithout any apparent cause, a panic seizes the men, and they halt in almost breathless silence. An old Indian officer has narrated many instances of this to me, and he states, that the panics are usually only momentary; * AVest])lial, " Archiv. fur Psj'chiatrie," vol. iii. ; Lej^rand dii .Saulle, " Annales Medicn-Psychologiqiies," 1876, p. 405 ; Ritti, " Diet. Encycloped. des Science* Mcdicales,"' art. '' Folie avec Conscience"; Ribot, "Diseases of the AVill," ]). ir, (Humboldt Series). DISEASES OF THE WILL. 451 for, at a word from the cominaiidiug officer, the men gener- ally pull themselves together, and, with a laugh, again fall into step. We now j3ass to the consideration of the second group of cases, in which there is impairment of the will through excessive activiti/ of the tneclianism of im^mlsion. The degree of con- sciousness of the operation varies considerably with different cases. Thus, the impulse may be sudden and without any fore- thought : the individual performs an action which is closely allied to the instinctive. In epileptics, hysterical maniacs, and in some forms of weakmindedness, with sudden explosive out- bursts, we find numei'ous instances of such excess of impulsion. Some patients, after an attack of an acute mania, will volunteer the information, that they were conscious of their actions through- out the whole attack, and that they could not account for the ex- traordinary things they did. Others are fully conscious of their own condition, and feel bound to perform certain actions which they at the same time condemn. A patient was brought to Bethlem bound hand and foot, at his own request, in order to prevent self- mutilation, which proved an ungovernable impulse to him. Another patient begged and implored that mechanical restraint might be emploj^ed to prevent him injuring himself. Instances of this kind are numerous ; and not infrequently patients will state, that the employment of some restraint to their actions has been a great source of relief. The fear of committing suicide, or of killing someone, often prompts patients to place themselves voluntarily under restraint. Thus, for instance, a bai'ber, admitted recently to Bethlem, felt the almost irresistible impulse to cut the throats of his cus- tomers while shaving them. Other examples, such as those of pyromania, kleptomania, etc., are so common that they need scarcely be referred to. Intoxication b}^ alcohol is especiall}^ productive of excessive impulsions. The usual explanation is, that the power of inhibi- tion is impaired, and that the reflex actions become excessive or violent as the case may be. The numerous cases recorded as instances in which the higher regions of the brain have been injured and the brain impaired have furnished several writers with the idea, that the will-power occupies a distinct locality in 452 THE WILL. * the brain. Ferrier has recorded a case in which, throiig-h injury to the prfefrontal region of the brain, a patient lost the balance between his intellectual faculties and his instinctive tendencies. He became nervous, disrespectful, and grossly profane. He showed but little politeness to his equals, was impatient of contradiction, and would listen to no advice that ran counter to his own ideas. At times he was exceedingly^ obstinate, though capricious and indecisive. He would make plans for the future, and forthwith reject them and adopt others. He was a child intellectually, a man in passions and instincts. Before the accident, though he had not received a school education, he had a well-balanced mind, and was regarded as a man of good natural abilility, sagacious, energetic, and persevering. In all these respects he was now so changed that his friends said they no longer recognised him. Ribot remarks, that in this case the will is impaired in proportion as the inferior activity becomes stronger. In all theories which seek to demonstrate how morljid symptoms arise as the result of activities within the undamaged remain- ing cerebral substance, we meet with the assumption, that all that is vicious, distasteful, and immoral is to be attributed to activities within these landamaged regions. In fact, some authors, in their endeavours to affix the physical evidences of dissolution to physiological factors, involve themselves in hypotheses as to the relative functions of nervous striactures which, on analysis, prove to be not only fanciful, but even absurd. Of these hypotheses, however, we shall speak more particularly in remaining chapters. Clinically, we have to note the following types of morbid impulse*: — (1) General impulsiveness, or the tendency to react immediately to all sorts of external or internal stimuli. Patients of this type break windows, strike others, and are continually getting into mischief. (2) Epileptiform impulses which are unconscious in character, or. in which, at any rate, the patient is unable to recall the reasons for, or the nature of, the impulsive act. (3) Sexual impulses, which include the excessive tendencies towards sexual intercourse, onanism, bestiality, etc. (4-) Morbid appetites in which * Clouston, " Mental Diseases." DISEASES OF THE WILL. 453 patients are unable to resist eating and drinking all sorts of filth. (5) Homicidal impulses. (6) Suicidal impulses. (7) Dipsomania, kleptomania, pyromania, etc. (8) Impulsive conditions which alternate with forms of intellectual or moral insanity. In some instances the morbid impulse is preceded by an aura similar to that of epilepsy. According to Bevan Lewis,* the morbid sensation is often peripherally referred, is of sudden accession, and may rapidly pervade distant parts of the body. Taylor, f Skae, Pinel, and Maudsleyij: have described the occuri-ence of various aurce, such as burning- heat in the epigastrium, constriction of the throat, colicky pains, flushings of blood to the brain, cold waves on scalp, etc. At certain critical epochs of life — e.;/., puberty, climacteriiim, and at menstrual and puerperal periods — there is often a ten- dency to excess of impulsion. According to Bevan Lewis, § homicidal impulses may prevail in one of four conditions in the epileptic subject — viz. : — (a) in epileptic furor or mania, associated with hallucination or delusion ; (l)) in the so-called "epilepsia larvata" (Morel), the "masked epilepsy" of Esquirol ; (c) in the dreamy state of epilepsy ; or, lastly, {(I) as a simple impulsive derangement during the inter- paroxysmal period. In the insane the various forms of morbid impulse are commonly found as follows : — («) The impulse to destroy, in mania, imbecilit}^ moral insanity, and dementia; (//) epileptiform imiDulse, in epilepsy, early stages of general paralysis, in the neuropathic diathesis generally; (c) sexual impulses — satyriasis in the male, nymphomania in the female — in maniacal states, at pubert}^, adolescence, climacterium, and at the senile epoch : ((/) morbid appetites — associated with menstruation, pregnancy, puerperium, and lactation, in acute mania, general paralysis, and in imbecility ; (e) homicidal impulses — in imbecility, masturbatic insanit}'^, puerperal, * "Text Book of Mental Diseases," p. 180. t "Med. Jurisprud.," vol. ii. p. 553. X " Responsibility in Mental Disease," p. 141. § Op. cit., p. 185. 454 THE WILL. epileptic, traiTmatic, alcoholic, religions, and dehisional insanities. Aboulia is commonly fonnd in simple melancholia, or in the early stages of mania, or of general paralysis. Hyperboulia is usually manifested as a condition of wilfulness in states of mental exaltation with excitement ; also in some forms of A\eak-mindedness and delusional insanity. 455 CHAPTER XIV. The Factobs of the Ixsaxities. Growtli and Development of the Mental Faculties — Development..! Processes in the Infant^Mici'okinesis — Micropsychosis — Rever- sion in Adults — Factors of Development. Internal Factors : — Original Capacities — Genius — Degeneration and Genius — Balance as the test of Mental Health — Genius a Suciulogical not a Psy- chological Concept — Hallucinations not Incompatible with Sanity — Mental Health not to be Estimated Entirely from nn Objective Standpoint — The Degenerate Advocates^Unreliability of Statis- tics — Inherited Disi:»ositions— The Views of Spencer and "Weis- mann — Hereditary Factors in Insanity — Consanguinity — Phthisis-) Scrofula, Gout, Kheumatisra, Syphilis — Alcohol — Diabetes — Neurotic Manifestations. External Factors : — Social Environ- ments — Psychopathic Epidemics — Children's Pilgrimages — Lycanthropy — liai>hania — Sensory Types — Religious Impot- tures — Sympathy and Mimicry — Endemic and Epidemic Psy- copathies — Folie a dewv — Ueligion — Physical Environment: Seasons — Climate — Occupation — Town and Country Life. THE FACTORS OF THE IXS-IXITIES. In speaking of the development of mental states, or of the human faculties, we must fully recognise that, as in the case of the physical organism, there is no parallelism betAveen groirth and develoinnerd. Mind is said to grow when it increases its stock of materials ; when it elaborates its materials into higher and more complex forms it is said to develop. With abnormal growth, development is sometimes impeded — e.g., in preparing for examinations the excessive growth of the bulk of- retentions may, for a time, impede true mental development • just as an excessive amount of nutriment may produce fatness, while, at the same time, rendering the physiological activities more 45G THE FACTORS OF THE INSANITIES. sluggish. When the mental retentions are elaborated, and their intellectual bearings reduced to the abstract, development results. If, however, they remain as mere retentions, growth results ; and, just as with phj^sical corpulency, we have lessened bodily activity, so \\'ith mental agglomeration, we have diminished power of thought. The develoiDment of the mental faculties involves an increased facility and rapidity of acquii'ed processes, requiring less effort or activit}^ on the part of the executive mechanism : new operations of the same grade of complexity become easier ; and with the increased capabilities, new operations of greater complexity and difficulty are more readily effected.* Exercise helps the physical organism to grow and to develop, and so with the mind, " exercise strengthens facility." How brain activity is brought about, or how it reacts on the particular structures engaged, we do not know : we can only assume, that with each activity some modification or physical disposition to act in a similar manner is created. The mechanical law is true under any conditions, and the repetition of the flow of nerve energy in definite directions gradually exerts a disposition towards activity being propagated along these lines of least resistance. In order that we may obtain some idea of the morbid processes of development of the mental faculties, it is advisable that we take into account the develoj)mental processes in the infant. Warner f has endeavoured to trace, from the movements of infants, indications of action in the nerve-centres, and thereb}' to demonstrate their spontaneity and impressionability to forces acting upon the organs of sense. By noting the attributes of the actions seen in series of movements as the evolution of the individual advances, he concluded, that some spontaneous movements indicated conditions of growth, while others were indicative of development of the mental faculty. The spontaneous (" microkinetic ") movements of the infant he regarded as analogous to the spontaneous movements in all young animals. J * Sully. " Outlines of Psychology," p. 42. f "Take's Dictionary," j). 465. J " Journ. Ment. Science," April, 1S89. GROWTH AND DEVELOPMENT. 457 With regard to the indications of mentation as observed in the movements of the infant, Warner says : — " Observation affords abundant evidence that the various members and parts of a healthy infant present constant movement while it is awake. " These movements in the new-born infant are not controlled through the senses by sight or sound, but movements of respiration and deglu- tition are controlled by impressions on the skin and mucous membrane. At this early stage we do not observe the phenomena of delayed ex- pression, cerebral inhibition, or compound cerebral action. " It is commonly said that the infant at birth does not give expression to the faculties of mind because it does not present signs showing that its nerve centres are impressed, even temporai'ily, by the sight of sur- rounding objects, its hands do not move towards objects within the field of vision, and none of its movements indicate that they are con- trolled by sight or sound. " When about three months old some control of movements through the senses may be observed, and the head may turn towards a bright light. " There is not much capacity for adapted action. " When the infant is about four months old, we find coming signs of impressionability to stimulation. Then the senses, the sight of objects, and sounds around, begin to control the microkinesis. " In the new-born infant it may be assumed that there is no menta- tion, no memoiy, no will. It is intrinsically possessed of a certain histological structure, with its proj^erties and powers of reflex action, microkinesis, susceptibility to impressions, received through the special senses. "Compare the action seen at birth with that seen at five months. Microkinesis still continues, but is capable of control by stimulation through the senses: it may be arrested temporarily by sight or sound, and this, after many repetitions, may be followed by new series of movements occurring upon less and lessstimulation, and with increasing- quickness and accuracy as time goes on. We infer a corresponding change in the nerve-centres. It appears that, whereas at birth they act slowly and independently of one another — as far as we know without any order in their acting — and the time of this action is not determined through the senses, at the age of five months they may temporarily be suspended from action by external stimulation, and during the time when no apparent currents are passing from them, undergo a change indicated subsequently by special combination and series of movements. This appears a great advance in cerebral evolution. " The following kinds of movements may then be seen in the infant : — Movements of the outcome of inherited conditions in the nerve-system (microkinesis). Movements following immediately upon stimulation by certain external agencies, as light, sound, etc. Movements resulting 458 THE FACTOIiS 0:< THE. INSANITIES. from the acquired association of nerve-centres. Movements similar to those previously resulting from a similar cause. Movements in different special areas, such as the small joints; asymmetry or symmetry of parts, etc. Action indicating delayed expression." When we consider these visible movements as indicative of the evolution of the nerve-centres, the first question we ask ourselves is : What is the significance of the movements which are universal at birth ? Warner says, " Each movement corre- sponds to actions in a nerve-centre, the mass of movements corresponds to a mass of nerve-centres in action. Further, these movements, as far as we can see, as to their tiine, and the parts moving, are not determined by forces arpund ; that is to say, the nerve-centres are not controlled in their attributes of action as to its time by external stimuli acting through the senses. We conclude that in the infant, iii it's earliest stages, the nerve-centres act separately and independent of special stimulation." Are we really in a position to ^ay that there is no mentation, no memory, no will in the new-born infant ? If with the first movement there is no corresponding first impres- sion in consciousness, then we are iii a position to assume that there is no mentation. This, however, we are far from being able to prove. Similarly with the .second movement, which should bear soriie relation in consciousness to the first move- ment if it is taken as involving the primary element of memory-. Unless, therefore, we postulate the' occurrence of mentation at the very beginning we become responsible for an account of its appearance at a period somewhere along the succession of physical phenomena. The term '' onicrojjsychosis'' is applied to the neural action corresponding to a certain known mode of irregular, spon- taneous uncontrolled thinking; but such an employment of the term is misleading, inasmuch as it is based upon an assumption which is unjustifiable, and would lead us to speak of matter in psychological terms. Because a mental act depends upon the formation of a didactic union among nerve-centres formed by stimuli from without or spontaneously, is no reason why we should term that physical process a psychical one. If we restrict the term ,to mean the exj^n-ession of mentation as witnessed in movements of the infant, we do not improve MICROKINESIS AND MICROPSYCHOSIS. 459 matters. The latter is apparently the way in ^Ahich Warner applies it. He saj^s : " The expression of all acts of psychosis necessitates the kind of neural action termed compound cere- bration ; we cannot then .expect to observe the expression of micropsychosis till we get evidence of acts of compound cere- bration occurring in the evolution of the brain as evidenced by adapted action in its visible parts. The first little adapted actions in the infant indicate compound cerebration, and pro- bably correspond to micro j)sychosis." From this it would appear, that the term " microkinesis " is applied to those move- ments which are spontaneous and purposeless, and " micro- psychosis " to those which are adaptive. The point we wish to be clear upon is, at what period of the evolution of the infant do the spontaneous movements become adaptive ? Does the first spontaneous movement form the basis for movements which become adaptive ? Or, to look at the question from another point of view, does the first adaptive movement evolve from some spontaneous movement, not at the beginning of the series, but at some later period ? The answer to this is clear. Every adaptive movement must take its origin from the .sum total of all the movements that have occurred before it ; that is to say, with the first movement we have the starting-point of the evolution of adaptive move- ments, and the microkinesis, in its physical sense, is synchro- nous in origin with the micropsychosis in its psj^chical sense. Warner fully appreciates the very early occurrence of thought or micropsychosis. He writes : — " The commencement of the rudiments of spontaneous thought in the evolution of tlie infant is not known to the physiologist — we cannot know the occurrence of thoughts before they are expressed by signs or words more or less like those used by adults. If thought depends upon the diatactic unions it may be assumed that such occur very early, tor we see signs of them in combinations of the spontaneous movements of microkinesis — diatactic unions occur Avith different discharge^-X)ro- ducing movements, and such may produce some vague thoughts. "We infer, then, that the neural action corresponding to the micx'opsychosis is a form of spontaneous diatactic neural action, not stimulated by the present surroundings, but due to inheritance ; it is known only, like all sorts of psychosis, by its subsequent expression. It is inferred t])at in the infant brain the centres act more or less separately and indepen- dently, but that when they act together they may correspond to 460 THE FACTORS OF THE ITsSANITIES. spontaneous thoughts; when they become controllable through the senses into special combinations, then they are signs of thought and intelligent action. Even later on in the child's life, much of its spontan- eous thinking and movement is not controlled by external impressions, but remains entirely spontaneous as micropsyohosis and mierokinesis. " It must not be supposed that in micropsychosis every act represents a definite thought, we do not say that every movement is a definite action ; special diatactic unions in combinations and series are called thinking, and special combinations and series of movements are called actions. The commencing signs of intelligence are actions following some stimulus, the intelligent character becomes more marked when we find some period of delay — a latent period — between the stimulus and its expression." The two tables constructed by Warner, to show the com- parisons and analogy between micropsychosis and mierokinesis in the infant, and the reversion of mierokinesis and micro- psychosis in adults, Avill prove of interest to the student. Infant Micropsychosis. There may not be defined thoughts. Dreams. A child's talk during play is frag- mentary. Early expressions of thought are vocal utterances — e.y., cooing, single words. Mierokinesis. There is movement, but no definite actions are performed. In sleep there are some spon- taneous movements. In play movements are spon- taneous. Simple acts or gestures feebly maintained. Reversion in Adults. Microlcinesis. Post- epileptic action. Fidgety movements. Movements in restless sleep. Uncontrolled movements. Movements controlled by sight. Micropi) there is a tendency to drink at an earlier age ; (c) the mental condition during drunkenness often reveals the inheritance of ideas or tendencies, which normally were kept in subjection; (^) the mental symptoms are often characterised by impulsiveness, and tendencies to commit rash acts ; (e) delirium tremens, transitory mania, and even epileptiform convulsions manifest themselves as symptomatic of a predisposition ; (/) in addition to suscep- tibility to alcohol, mental perversions may be caused suddenly by exciting causes in which alcohol plays no immediate part ; (g) alcohol may determine a psychosis which is inherited ; [Ji) the predisposed individual tends more to misinterpret his sensory impressions ; (?) the mental states or ideas are changeable, and constantly interrupted by lucid intervals ; (j) the melancholic symptoms are somewhat different, and suicidal tendencies are thought by some authors to be an indication of a special predisposition. Legrain* gives four varieties of the special predisposition to suicide in these cases — viz.. (1) Instead of having the form of genuine alcoholic suicide (an accidental act, or caused by fright in consequence of special hallucinations), the tendency is logically connected with the melancholic ideas as expressed by the patient ; (2) sometimes those who relapse into delirium tremens attempt suicide at each attack ; (3) in the course of one and the same attack of delirium tremens, several attempts may be made ; (4) in the ancestors of drinkers who become melancholiacs and commit suicide during an act of delirium tremens, a special predisposition to melancholia exists. In a predisposed individual, it is not uncommon to meet with maniacal conditions of an ambitious or an exalted kind. * " Tuke's Dictionary," p. 71. HEREDITARY NEUROSES. 479 In an attack of delirium tr-emens in a person predisposed, the delirium lasts longer and is more apt to be follo'\\'ed by another psychosis, than in the case of one \\-ho has not the predisposition. Diabetes. — The frequency of the occurrence of diabetes in the parents or near ancestors of insane patients is noteworthy. Savage believes that its occurrence is chiefly among the affluent classes. Whether there is any direct relationship between insanity and diabetes, we are as A^et unable to say. From the records of Bethlem Hospital it would appear, that most of the cases with a family history of diabetes have been of the melan- cholic or hypochondriacal type. This confirms the observations of Savage, who also noted that the periods of adolescence and the climacterium were especially prone to favour the occuri-ence of neuroses in siich cases. Other morbid factors, which tend to determine the life-histories of a family, might be mentioned ; but the scope of this work will not allow us to do justice to the innumerable investigations that have been made. We must, however, note one or two of the main functional and oro-anic diseases of the nervous system, which appear to be the result of ancestral taint, and which alternate or interchange in the life- history of the individual or of the race. There are some inherited neurotic tendencies which do not become manifest unless -the individual is subjected to exciting- causes. Such individuals are excitable, eccentric, very suscep- tible to shock, passionate, and easily affected by alcohol or by injury to the head. Others are affected by migraine, neuralgia, headaches, sensory epilepsy, spasmodic asthma, neurasthenia, and other neurotic manifestations. The various forms of mental disease in the adult may be, in great part, due to neurotic inheritance. General paralysis ma}^ be in part due to inherit- ance, but it is more common for the offspring of general paralytics to be neurotic. There are other forms of inherited neuroses which are apt to develop in the life history of the individual. Chorea, hysteria, and some forms of epilepsy, may develop into grave forms of mental disturbance. Sometimes a strong neurotic inheritance develops early in the life of the individual, and manifests itself in the graver forms of epilepsy, moral insanity, or 480 THE FACTORS OF THE INSANITIES. criminality. In infancy a strong inheritance may show itself in convulsions, epilepsy, hydrocephalus, imbecility, or idiocy.* External Factors in Development. — Social E71- vironment. — That the social environment of Avhich we are members may influence our minds through the media of our sense-impressions, there can be no possibility of a doubt. Not only are we influenced morally and intellectuallj^ by our social surroundings, but our mental development would be but rudimentary without them. As we advance in life these social influences gradually increase in complexity. That they are essential to the mental development of the ordinar}^ individual is manifest ; but, as already pointed out, they are not everything to the manifestations of genius. The influences of societ}'^ upon an individual may be exerted in a natural way — i.e., the individual adopts the prevailing tone of thought of his family and immediate acquaintances. It is impossible to extend our range of view so as to include all that belongs to social life ; nor can we attempt to consider all the implications of moral life, nor how moral law influences social life, organisation, and government. A philosophy of moral life would have to include the whole range of social questions. Just as the unity of a familjr is founded on biological and ethical laws conjointly, so all the relative duties of the social life conform to those universal laws which exist in accordance with the bonds of nature. Here we have only to consider how members of a society may combine to predispose the generation of a morbid psj^chosis. In the struggle for existence the stronger often carries off" the prey from the weaker. In the building up of character in man and of mankind generally, there is an enlargement of the evolutional activity, a finer elaboration of the moral and intel- lectual contents of consciousness, and the executive effectiveness * See Revington, " Neuropathic Diathesis," Journ. Ment. Science, April and July, 1888; Mercier, "Sanity and Insanity," also " Heredity "^" Tuke's Diet." ; Thomson, " Hereditary Nature of Crime," Journ. Ment. Science, vol. xv. p. 487 ; Spencer, " Principles of Biology," Part II. chap. viii. ; Dunlop, " Illus- trations of Heredity," Journ. Ment. Science, vol. xxvii. pp. 39, 1.31 ; Dexter, " Heredity," ibid., vol. xxii. p. 152 ; Compayre, " Heredity in Children," ibid. vol. xxvii. ii. 29. PSYCHOPATHIC EPIDEMICS. 481 of volition is progressively acquired. At any period of our habitu- ated cerebration, contrarieties of motive may affect the e(jo and germinal power of self-determination, and, by persuasion, cause the ego to decide arbitrarily, by fresh importations of energy, options which are significant of deterioration or dissolution. The whole historj^ of the world is covered by the shadows of beliefs, germinated endemically and in ignorance. Social requirements and traditions have given rise to the most diverse religions, views, and modes of life. It is susceptible of proof that, with the increase of refinement, the occurrence of nervous and mental disorders has increased in a proportion which has been maintained to the present day ; and, inasmuch as this subject is of great importance to the community, we must devote some time to its consideration. Psychopathic Epidemics. — Many of the narratives recorded in the Old Testament, and some of the Sac/jtovl^ofievoc in the New, are ascribed hj some authors to madness. Greek mythology, in the stories of Hercules, Ajax, Orestes, Athanias, and Alcmaeon, touches on these phenomena and on lycanthroj)y, and the madness of the daughters of Proetus, and the uterine disease of the Lythians are even quoted as examples of epi- demical psychopathies.* We have examples of manj^ psychical anomalies from the work of Galen. f The monomania of the Silesian maidens, | and the feverish psychical excitement of the inhabitants of Abdera, after witnessing the performances of the Andromache of Euripides, are adduced as being in some degree instances of an epidemic psychopathy. Many of these accounts of the ancients are, however, hardly germane to the inquiries of the alienist or the philosopher. And then again, the undefined word madness used in reference to religious matters is often misleading. All ages seem to have been characterised by absurd fables and exaggerated speculative conceptions. Ever, in the history of the world, new and mighty movements have agitated all nations, awakening men from their dream of permanent repose, and convulsed the whole or parts of the civilised uorld. * Frieder, " Litt. Gescli.," 17 etc. t " Diseases of the Mind." X " Plutarch de Virtut. Mulierum." 31 482 THE FACTORS OF THE INSANITIES. In the middle ages destnictive epidemics, for the most part advancing from east to west, visited the whole of the kno\\'n earth ; characterised during the earlier periods of this epoch, rather by cutaneous affections, and during the later, by- affections of the abdominal organs and sensori-motor system.* Of the latter we may specially notice the dancing mania (pilgrimage mania), f which first appeared about the year 1212. Thousands of young people, mostly approaching the age of puberty — i.e., from twelve to eighteen — assembled together, and formed what were called " children's pilgrimages." They proceeded (1237) till they sank exhausted to the ground, so that many died, and the survivors were afflicted with tremors which continued as long as they lived. This disorder seized boys and girls suddenly, and, together with other phenomena, was combined with a morbid antipathy to red colours and to weeping; and, when the disease was at its height, tympanic swellings of the abdomen ensued, and parox3'Sms of howling, screaming, leaping, and an excessive love of dancing set in. In the time of Paracelsus the form of this disorder was milder, and approached that of St. Vitus's Dance. Haser com- pares this epidemic with the lijcanthropy of the ancients. However hypothetical any notion may be, which we are able to form as to the nature of this disorder, a psychical momentum was certainly in operation, | and a very able writer § treats even the Crusades as an epidemic of mental disease. At the begin- ning of the eighth century rapJiania, which often commenced with mania- and terminated in imbecility, became particularly prevalent. Webster speaks of an epidemic madness which prevailed in England in 1354, which attacked the lower classes, and subsequently spread through France and Italy. " During periods of plague," he adds, as if by way of explanation, " some general influenza appears to have seized the brain, even of persons who were not attacked by the plague itself." Since the middle of the eighteenth century neurotic storms in social life have become more and more developed. || Un- * Haser, " Geschicte der Epidemisclien Krankheiten." I Hecker, " Die Tanzwuth." X Feuclitersleben, "Med. Psycli.," p. 42. § Wawriich, " De Morb. Pop.," (MS). II Leuj)holdt, " Gescli. d. Ges. n. Krankh." 13G. PSYCHOPATHIC EPIDEMICS. 483 doubtedly all ages have been characterised by absurd beliefs and speculations ; and the mental epidemics of the days of old are thought by some writers to have their equivalent in the mental rhapsodies of the present day, as shown in almost incredi- ble psychical deviations and beliefs in the fantastic and unreal. The mystical aberrations of primitive people, were, in their universality, no more within the actual borderland of true psychopathy, than many superstitious beliefs and traditions of the present age. The endemic beliefs, with their histories and endless variations, however, do not form part of our subject ; so we propose to deal more particularly with those morbid manifestations which have passed the borderland of sanity, and in their nature and violence have appeared as clearly marked epidemic psychopathies. Considered seriatim, the various psychopathies ma}^ be de- scribed, as the}^ have been characterised, as purely mental or moral perversions, or as physical aberrations secondary to the physical contagion. Of the sensory type, the world has witnessed many curious illustrations. The spectral illusion occurring on the banks of the Clyde (168G) affected a great many persons who saw, while others failed to see, companies of men in arms marching along and disappearing. They also saw bonnets, guns, and swords. In this instance, emotional predisposition doubtless favoured production. There is a striking observation made by Theresa, whom M. Maury characterises as the metaphj-sician of feminine mysticism and of ecstatic illumination — namely, '• I have known some of weak mind who imagine they see all that the}^ think ; and this," she adds, "is a very dangerous condition." Many writers believe, that whatever mental or bodih' state can be excited through the senses from without, may also arise from within from imagination proper. It is this principle which continually turns up in the consideration of the cjuestions now engaging our attention, and which would seem to enable some psychologists to form a successful clue to many otherwise inexplicable sensory manifestations. We have already seen that, whatever the cause may be, in some conditions of the brain, the sensory centres may be so powerfully excited that the effect is identical in sensory force (in objectivity) with 484 THE FACTORS OF THE INSANITIES. that which results from an impression produced upon the peripheral terminations of the nerves, causing hallucinations or phantasmata. The mind, under certain circumstances, can, by attention, recall the sensorial impression so distinctly, as to produce (e.g., in the case of sight) the spectrum or image Avhich was impressed on the retina and perceived by the sensorium.* It cannot be denied, however, that there are sensorial phenomena, whose origin, at any rate at present, cannot be explained by an exercise of the imagination process, as such, either voluntary, normal, or unduly stimulated. Yet many of the astonishing psychological dramas which have at various epochs arrested the attention of the world, have arisen through phenomena allied to the products of the imagination and propagated by imitation.! At the present day we look back with a degree of wonder at the belief in witchcraft, \\hich may be said to have formed an article of religious faith in every European country throughout the sixteenth and seventeenth centuries. A notion was uni- versally entertained, that the devil and some subordinate evil spirits, in pursuance of their malevolent ends, went about, sometimes in visible shape, seducing poor human nature. Such " trafficking with the powers of darkness," as it was technically called, was witchcraft, and, according both to the letter of Scripture and of civil law, was a crime punishable with death. Originating in ignorance, together with a love of the mar- vellous and from many religious misconceptions, the belief in witchcraft maybe traced through the earl}^ ages of Christianity; but the modern prevalence of the delusion may be said to date from the promulgation of an edict of Pope Innocent VIII., in 1484, declaring witchcraft to be a crime punishable with death. Like all popular manias, the witchcraft delusion had its paroxysms. It followed the well-known law of supply and * Hack Tuke, Body and "Mind," p. 80, vol. i. t Due to imagination, understood in tlie sense of expectation, we have, • as examples, the Okeys, the Wizards of Kamschatka, tlie Whirling Dervishes of India, the Second Sight Men of the Highlands, the Serpent Eaters of Egypt, and the Wise Men and Prophets who may still be found in York- shire, all knowing how to excite convulsions, or delirium, or spectral illusion and somnambulism in themselves or their dupes, by mental acts or drugs. PSYCHOPATHIC EPIDEMICS. 485 demand, and the frenzy never lacked victims. As soon as witches were in request they made their appearance. The folly while it lasted was complete, and received the solemn sanction of people of every quality and profession. It is a curious law of human nature, of which we have seen many modern illustrations, that even crimes, real or imputed, when they excite much public attention, tend to produce repe- titions of themselves. In this way, such oifences sometimes assume a character approaching that of epidemical diseases. In 1515, during the space of three months, 500 witches were burned in Geneva ; in a single year, in the diocese of Como, in the north of Italy, 1,000 were executed; and it is related, that altogether more than 100,000 individuals perished in Germany before the general mania terminated. In France, the belief in witchcraft led to a remarkable variety of superstition, known in French law as hjcanthropij, or the metempsychosis of a witch into a wolf. In the reign of Henry VIII. , 1541, Elizabeth, 15(32, and also of James I., witchcraft, though alwaj^s penal, then became of itself a cajntal crime. James I. passed an act in the first year of his reign, which, on account of its degree of minuteness, is almost unprecedented. He defined witchcraft distinctly, and enacted that, "Any one that shall use, practise, or exercise any invocation of any evil or wicked spirit, or consult or covenant with, entertain or employ, feed or reward any evil or wicked spirit, to be for any lyarpose, or take up any dead man, etc. etc. etc. ; such offenders, duly convicted and attainted, shall suffer death." Many years had not passed a^way after the passing of this statute, ere the delusion, which had theretofore caused but occasional and local mischief, became an epidemical frenzy, affecting every corner of England. The revolting crimes of the monster, Matthew Hopkins, who, with his assistants, moved from place to place in the regular and authorised pursuit of his trade of witch-finding, will give an example of the horrible fruits of the witchcraft frenzy in general. From each town he visited, Hopkins exacted the stated fee of twenty shillings ; and in consideration thereof, he cleared the locality of all suspected persons, bring- ing: them to confession and the stake in the followino; manner : — 486 THE FACTORS OF THE INSANITIES He stripped them naked, shaved them, and thrust pins into their bodies, to discover the witch's mark ; he wrapped them in sheets, with great toes and thumbs tied together, and dragged them through ponds and rivers, when, if the}^ sunk, it was held as a sign that the baptismal element did not reject them, and they were cleared ; but if they floated, as they usually would do for a time, they were then set down as guilty, and doomed. In short, such abominable cruelties were practised upon the accused, that they were glad to escape by confession. After he had murdered hundreds, however,- the tide of popular opinion Avas turned against him, and he was subjected by a party of indignant experimenters to his own favourite test of swimming. It is said he escaped with his life, but from that time forth he was never heard of again. It A\'as during the era of the Long Parliament that the growth of witch-mania proceeded. Three thousand persons are said to have perished, during the continuance of the sittings of tliat body, by legal executions, apart from many summar}- deaths inflicted by a ruthless mob. This long and black cata- logue of murders was only completed after the number of those put to death had reached 30,000. Thus, we have with the " D^monologie " of the sapient James a record of a popular mania, which in time would have abated, had not the spirit of Puritanism gained strength, and the belief in witchcraft, by the great and educated, had the natural effect of i"eviving the frenzy among the flexible popu- lace. Once more the old impossible and abominable fancies were revived, but this time witchcraft assumed the form of a religious persecution, and with even a deeper degree of attendant horrors than at anj'" other time. This mania was not confined to Great Britain, but ex- tended with virulence to North America, where the inhabit- ants, carrying their religious opinions to excess, yielded a remarkable credence to the popular superstition, and carried it as far, in their modes of judicial punishment, as it had gone in any European nation. Of the ultimate causes of such transient delusions which run so high and terminate so fatally, no definite explanation can be given. Such moral desolations often pass over the RELIGIOUS IMPOSTORS. 487 face of society. The thunderstorm does its work^the atmo- sphere becomes clear, and the sun shines forth and reveals to all the work of death. Next, we come to the spirit of the religions pilgrimages of which we have spoken. On the establishment of Christianity in the Roman Empire by Constantine in the year 321, Palestine and Jerusalem became objects of interest to all Christians, and crowds of pilgrims flocked to the localities celebrated by the ; Evangelists ; but it was not until Peter the Hermit, with his strange and wild aspect, his glittering eye, his shrill and unearthly elocpience, and the grandeur of his theme, had traversed the whole of Europe, and had produced everywhere the most extraordinary sensations by his pathetic descriptions of the state of Jerusalem and the Christians there, that the love of adventure, the spirit of chivahy, and the desire to wage deadly war with falsehood and guile, burst into a passion so powerful and deadly, that the force of it not only overmastered thousands of noble and refined human beings, but compelled into his heterogeneous train, robbers, murderers, and all sorts of criminals, until the vast masses set in motion towards Holy Land amounted to millions of souls. Evidently, ver}^ numerous were the miscreants and fanatics of that age ; poor ^\•retches who had been hurried on by a blind, impulsive kind of mania into the enterprise, without forethought or preparation of any sort, and whose main anxiety was to be the first to reach the sacred shrine. There were to be seen hundreds of thousands of human beings, the mere tools of the enthusiasm, and the monster result of that grief and rage which had filled the breast of Peter the Hermit ; and the conclusion and consummation of their desire was a carnage and work of blood in the redemption of the very birthplace of the religion of peace. Beligious Impostors. — Of religious excesses originating in imposture, or the delusions of overheated neurotic tempera- ments, the world has had many lamentable examples ; and of all excesses, that of excess in mistaken or misguided devotional feeling has proved the most dangerous. History abounds in accounts of Messiahs, and of their contagious influence and temporary success in working on the credulity of their followers. We have only to mention the Munzer fanatics in Germany, 488 THE FACTORS OF THE INSANITIES. who, amid the turmoil of the Reformation, by their pretended visions, miracles, and prophecies, kindled the flame of fanaticism in the minds of the peasants ; and the equally infatuated zeal of the followers of Bockholt or John of Leyden. Here, in both cases, the doctrines of an hallucination spread into a popular belief which held its sway over great multitudes of people. In almost all countries of Europe an enormous number of these people preferred death in its worst forms to a retraction of their beliefs. Neither the vie\\' of the flames kindled to consume them, the ignominy of the gibbet, nor the terrors of the sword could shake their invincible constancy, or induce them to abandon tenets that appeared dearer to them than life and all its enjoyments. The would-be more enlight- ened policy of modern times would either leave alone siich beings, or, at the most, endeavour to consign them to the humane treatment of a lunatic asylum. The mass of absurdities — blasphemous in the extreme, if viewed as the outpourings of mental sanity — of the New- foundland prophet, Richard Brothers, excites a sense alike of the painful and ludicrous. That the man was neither more nor less than a confirmed lunatic may be easily seen by the perusal of the gross specimens of his ravings as set down in his work, called '• A Revealed Knowledge of the Prophecies and Times." The victims of such a contagious epidemic create a world of their own around them, and in imaginary inter- course with the beings that people it, find more pleasure than in any commerce with the material creation. Richard Brothers, as far as he lived at all for the ordinary world, lived only to afford another proof of the irregular exercise of the superstitious feeling and love of the marvellous in man, as well as of the difficulty which even education has in repressing their undue exercise. During the past century the religious world has been scandalised by the wild fancies and pretensions of several female fanatics, equally mad or self-deceiving with the most visionary impostors of the male sex. Anna Lee, the founder of the religious sect commonly called Shakers, was a violent, hysterical, vehement, and ambi- tious girl, who claimed to be the Bride of the Lamb seen in Revelation by St. John. Yet, such was the powerful influence SPECULATIVE MANIAS. 489 of the morbid visions of this illiterate, hysterical factory-girl, that the course of American thought and sentiment was con- siderably altered by it. The extravagant pretensions of the fanatics Jemima AVilkinson (" the universal friend"), Mrs. Buchan ("mother of the elect"), and Joanna Southcott. with her 100,000 excited followers, are other instamces of uncouth epidemics, in which thousands of crazy dupes became infected by the crude and oftentimes coarse raving of a maniac. The religious wanderings of Matthews, " the prophet," excited a frenzy in America, which in ordinary times would lead to no other result than the committal of such a madman to an asylum. The assumption of Divine power by John Nicolls Thoms in Cornwall, was followed by confinement in an asylum, but not until his exhortations and denunciations had induced an enthusiastic fervour amongst his vast concourse of deluded followers. Lastly, mention must be made of the 80,000 enthusiastic disciples of Sabbathias Zwi, A\ho claimed to be the Messiah, and endeavoured to convert all humanity by the magic and mystical doctrines of the Cabbala. Closely allied with hysterical insanity on the one hand and epileptic insanity on the other — and when ceasing to be sporadic, forming the best illustration of epidemic insanity — is a form of mental disorder known under the various designations of Taran- tism, Dancing Mania, Tigretier, Chorea-Demonomania, and Choreomania, but which must not be confounded with ordinary chorea in combination with insanity.* It consists of an irresist- ible impulse to active movements, remarkably stimulated by music, Avith marked perversion of the feelings. On several occasions this remarkable disorder has deeply affected the course of political and religioiis national life.f Speculative Manias. — Another important series of epidemics are catalogued under the speculative manias, among which the avaricious desire of being speedil}^ rich has been a prominent * Bucknill and Tuke, " Manual of Psychological Med.," p. 400. t Dr. Tuke has given the narrative of epidemic choreomania occurring in Madagascar, "Manual of Psych. Med.," 3rd edit.; and Dr. Constans has given an interesting account of the " Epidemie d'Hystero-Demonopathie," in 1861, at Morzines, in the Department of Chablais (in Haute-Savoie), Paris, 1863. 490 THE FACTOUS OF THE INSANITIES. feature. Sometimes the schemes, though visionmy, arose with no bad intention, laeing nierel}^ a consequence of inconsiderate enthusiasm ; but in others, if not originating from deception, tliey were continued with a reckless disregard of consequences, and evidentlj^ for the sake of immediate and iinjustifiable returns. John Hunter laid down the law, that " ever}^ part of the body sympathises with the mind ; for whatever affects the mind, affects also the bod}" in proportion." * The mischievous influence of sympathy or imitation is exemplified in the following case quoted from Dr. Tuke's work. In a. workshop where sixty Avomen were at work, one of them after a violent altercation with her husband had a nervous attack. Her companions pressed round her to assist, but no sooner had they done so, than first one, then another, fell a prey to the same kind of attack, until twent}" were prostrated by it. The contagion appeared likely to spread through the company, but Mas checked by clearing the room.f That there is a pernicious influence in connection with reading the graphic reports of atrocious crimes is at the present day manifest ; the images of these crimes are impressed upon the mind through the senses, and "sA'ith defective control there is simply a reproduction of the acts as pictured. There can be no doubt, that siiicide is frequently brought about by suggestion in this way. A case is qiioted by Tuke of a sentinel in Napoleon's ann}^ who com- mitted suicide by hanging himself in his sentrj^-box, and whose example was immediately followed by several others, when they became his successors in the same box, until Napoleon found it necessary to entirely destroy the box by fire. The comparatively recent epidemic of suicide among the j-outh of Austria furnishes us with another illustration. Everj^ youth who failed, or nearly failed, or fancied he might fail at any examination whatever, immediately began to think of suicide, and sometimes even committed it, without waiting to hear the result of the examination. Of mimicry of disease there are innrmierable instances. The cases quoted by Weir Mitchell, of six or seven inmates of the * Tuke, " Influence of Mind on Body," p. 167. t " Journ. des Connaissances Med. Chir.," Feb. 1, p. 16, 1851. MIMICIIY OF DISEASE. 491 Pennsylvania Hospital who imitated another patient suffering from croup ; and Durand's account of the influence of imagina- tion causing vomiting in 80 out of 100 patients simultaneously, exemplify the influence of suggestion. Tamburini and Tonnini* make a distinction between endemic and epidemic insanity. Endemic insanitj^ is confined to one region or district, but may extend and become epidemic. Besides their local character, the particular forms of endemic insanity are described as being stable, and as tending to propa- gate without any active moral contagion. They are also thought to reflect the tendencies of primitive races. When the endemic psychopathies spread among people of different habits and conditions, the disorder tends to become less intense and less frequent. Epidemic insanity extends over a much larger area than endemic. The epidemics may develop under the influence of the same psychological tendencies — i.e., the same morbid tendencies may exist throughout a large number of individuals. It is more common, however, for an epidemic to arise through the influence of some individual who infects others with his own morbid ideas. The psychic manifestations maj?" take the form of (1) illu- sions or pure hallucinations, which affect man}^ persons at the same moment ; (2) morbid psychoses, in which there may be melancholia, excessive religious zeal, political or pseudo-scientific intemperance ; (3) sensorj' perversions with ecstasy, impulses, and morbid activities ; (4) actual convul- sive attacks, as in the various epidemics of hysteria, epilepsy, and chorea. Insanity may be communicated {Folie d deux) from one individual to another m various ways : — (1) Occasionally one patient becomes infected by the mental disorder of another. Not only may the actual existing delusion or moral perversion be communicated, but also numerous abnormal activities, such as the rhythmical movements of idiots. Thus, in County asylums it is not uncommon to see several insane individuals of a degraded type who have copied the perverted activities of their neighbours. (2) In consequence of the shock of witnessing an attack of insanity, and the strain occasioned by nursing, etc., * " Tuke's Dictionary of Psychological Medicine," p. 434. 492 THE FACTORS OF THE INSANITIES. some individuals break down mentally and may acquire the same insane ideas as their patients. These instances of course differ from those in which two or more persons liecome insane simultaneously from the same cause. On the whole, however, from an analysis of the clinical facts, it would appear jiTstiliable to state, that (1) the insane have little influence upon the sane — i.e., other things being equal, attendants upon the insane are not especially liable to attacks of insanity. (2) When an individual breaks down in conse- quence of association with the insane, the probability is, that that individual has a neurotic inheritance, or is subjected by disease or other causes to mental and physical strain. (8) It is more common for women to break down than men. (4) The young are more likely to become affected by the delusions of the old than vice versa ; especially if the old are related to, and intimately associated with, the development of the former. (5) An individual who is obviously insane seldom influences the thoughts of those who are sane. The greater danger arises from the insane person who is able to conceal his madness and apply his intellect in a methodical way, so as to influence another in the direction of his own delusion.* Delusions of persecution, and the beliefs in conspiracies to defraiid of property, are the commonest forms of communicated insanity. Patients seldom mimic an attack of mania, melan- cholia, or dementia. Occasionally among the hysterical there is mimicry of the paralytic affections of their neighbours. One patient at present in Bethlem has copied the incoherence of a maniacal patient, but his efforts have the appearance of being voluntary, and the seriality of thought is too evident to resemble the rapidity of utterance, and the inconsequent ramblings, of the acute maniac. Of direct stress and the various physical caiises of insanity we shall speak in the next chapter. It only remains for us now to sum up our conclusions with regard to the influence of our social environment. Sooner or later the question must arise within the mind of each of us whether, as physicians, it is our dvity to study man as man, devoting ourselves to the contemplation of the mental * "Tuke's Dictionary of Psychological Medicine," p. 241. EELIGION. 493 faculties possessed by him in a greater degree than any other animal, and to apply these laws as principles for the synthetical explanation of the phenomena of the understanding, and thereby support the philosophy which Hippocrates contem- plated, and which led him to give the character of " Divine " to the medical art ; or whether we are to brand ourselves with the reproach of advocating an irrational materialism. When we reflect that, in the old-world days, the relations of mind and bod}^ were recognised and discussed in their various bearings, and that the fundamental problems of Hippocrates are still unsolved, we marvel that, even at this day of methodically regni- lated exj)erimental investigation, we are no nearer the solution of the all-important problem of the ultimate relation of the mind and bod3^ In the history of philosophy, we see in clear detail that all our modes of thought, so far as they rest on specific funda- mental differences, have been anticipated in the systems of the Greek philosophers. No matter how the various problems may clothe themselves to us, the human mind has always been con- fronted with the same metaphysical hnpasse. When we review the philosophy of to-da}^ we see its exact representation in antiquity. Plato's " Freedom of Rational Ideality," Aristotle's " Legality of Intelligible Realism," Zeno's " Intellectual View of the World," and the materialistic views of the Epicureans, fully represent the possible directions of our own present thoughts. The philosoph}^ of the infinite, far from becoming a source of aberration of thought, is the ultimate point of our mental evolution. Beliefs which are narrow and deal with traditions in the concrete are but symbols of dissolution. A true and philosophical religion raises the mind above a mere incidental emotionalism, and gives stability. With no religion, and no moral obligation, the organism becomes a prey to all the lusts of the flesh with their consequences. Gasquet* observes, that religion may either produce or tend to hinder unsoundness of mind ; that it may cause certain symptoms of insanity, or modify them ; and lastly, that it may be- employed as a means of moral prevention and treatment. He believes, that every * "Tuke's Dictionary," p. 1088. 494 THE FACTORS OF THE INSANITIES. religion, however widely it may differ from our standard of the truth, if it enforces the precepts of morality, is a source of strength to the sound mind that sincerely accepts it. " An agent which can effect so much good must, however, be equally potent for harm. The mind on which religion acts may be abnormal ; in which case it is not wonderful, as an old author puts it, ' that the light should be painful to the sick eyes, which to healthy ones is de- lightful.' Or the fault may lie in the application of religion, like a drug which can save a life, but is equally able to destroy it, if given inoppor- tunely or excessively. The sense of responsibility to omniscient justice may pass into a belief in condemnation irrevocable and inevitable ; the habit of communing with God may easily grow into self-contemplation and ecstasy ; the repression of the lower part of human nature may be strained into practices ruinous to health of mind and body. The common factor in all these exaggerations is fanaticism, which looks only at one side of religion, and commits the fallacy of supposing that the depend- ence of man upon a higher being must supersede all those other duties which, on the contrary, derive therefrom their greatest sanction. As one of the natural growths of an ill-balanced mind, fanaticism is closely akin to the other manifestations of the insane temperament : and this accounts for the fanatical habit of mind that is so often associated with the hereditary neuroses, above all with epilepsy. Overstrained and one-sided religious views are, however, not so often the primary cause of an attack of insanity, as its first symptoms, though symptoms which in turn act as causers of further evil and intensify the disease. For instance, an endeavour to study the mystery of existence and solve the problem of evil has been rightly denounced as highly dangerous to mental health ; yet it is recognised as an early symptom (' C4riibelsucht') of an otherwise deranged mind. Or, again, a case of melancholia in Avhieh religious delusions seem at first sight to have been the cause of all the troubles, will be found, if traced from the beginning, to have originated in disordered bodily health.'' The same author believes, that a dehision which is to account for the morbid feelings of a lunatic must be constructed out of the previous beliefs, and that many religious delusions must, there- fore, be confined to the members of particular religious bodies. The form of mental disorder generally determines the colouring of the religious delusion : thus maniacal patients have exalted delusions; melancholiacs depressed ones; general paralytics those of an inconsis<"ent and wild character; while chronic delusional cases have more or less definitely fixed ideas that they are special messengers of God, or even the Almighty Himself. Oasquet mentions the mixture of erotic and religious excite- PHYSICAL ENVIRONMENT. 495 ment in many epileptics, the simple belief in perdition common in amenorrhcBal melancholia, and the manner in which insane masturbators will assert that they are heroes and martyrs under some special dispensation of Providence. Dr. Hack Tuke classifies religious delusions according as they (1) accompany the mental development of over-stimu- lated and injudicioush' educated children (fear, remorse, etc.) ; (2) characterise the insanit}* of pubescence (fear, depression, and wish to do penance) ; (3) are caused by self-abuse (self conscious, unpardonable sinners, Aveak minded, auditory hallu- cinations, visions, trances, ecstasies, suicide) ; (4) are associated Avith (so-called) paronoia (delusions of superior spirituality, fanaticism) ; (5) are associated with epilepsy, dementia, and general paralysis (rarely fear, usually unworthiness, or exalted ideas) ; (6) are observed in melancholia and climacteric insanity (unworthiness, fear of endless life, etc.) ; (7) arise in chronic mania or toxic insanity (usually exalted). Physical Environment. — Tie Seasons .- Climate. — Par- chappe and Esquirol have estimated that admis.sions into asylums are more numerous during the summer months. Guislain believes, that there is some relation between the warmth of the atmosphere and mental disturbance. Aubanel and Thore also formed the same conclusions. Guislain has pointed out, however, that we do not find more insanitj- in hot climates than in cold.* Moon.- — -The influence of the moon is doubtful. ]Most modern observers believe, that mere increase of light is suffi- cient to cause the excitement in some patients. Occwpation : Toivn and Goitntrij Life. — Sibbald believes, that of insane patients a more considerable proportion may be assigned to previous urban surroundings than has generally been supposed, that cases of general pai'alysis and other rapidly fatal diseases of the nervous system are more common under the conditions of town life, and that attacks of insanit}-, swift in their onset and swift in their retreat, are also more common. The general opinion now is, that civilisation, abounding A\ith artificial conditions and influences, is the most general cause of stress and strain, and, as a consequence, mental disordei", irre- * Bucknill and Tuke, " Psychological Medicine," p. 78. 496 THE FACTORS OF THE INSANITIES. spective of any special occupation or locality". When we discussed the special senses, we took account of the forms of iUusion as determined by the environment and hj the organism, and we saw how unusual relations between the phj'sical environment and the organism afforded data for misinterpretation by the mind. In conclusion, the student will do well to bear in mind, that next in order to the process of determining the nature and significance of phenomena is that of discovering their causes. We cannot afford to dispense with philosophy, for it is by that, in our efforts, the laity are most apt to measure us. Instead of bewailing our ignorance of natural causes as the most fruitful source of superstition and disease, it is our duty to exert the prerogatives of philosophy, and to endeavour to free ourselves from the traditions and shadowy appre- hensions of others. It is eminently true of the medico-psycho- logist, that the fears and hesitancy with which he approaches the treatment of mental disease are in exact proportion to his ignoi-ance of its causes. If he is only a physiologist, or only a psychologist, he does not possess that privileged understanding of cause which alone can give him confidence. He must be both. He must combine a philosophy with a handicraft. In his efforts to combine the two, however, he must beware how he proceeds. Nearly fifty years ago Simon said, " It would be difficult, in polite language, to find phrases sufficiently strong for stigmatising, according to its deserts, the state of medical aetiology In the absence of exact physiology how, indeed, could it exist, save as nurses' gossip and sick men's fancies, and the crude compilations of a blundering empiricism?" Since this statement was made great advance has taken place in many departments of our science. We still, however, are asked to accept many vague generalities of expression. At every turn we are asked to rest satisfied with post hoc, ergo propter hoc, as our indiTctive formula. Some of our most advanced schools of thought ivy to teach us to say. " I don't know I am sure " instead of " I am sure I don't know." Lord Bacon reprobates the " over-earl}'' and peremptory reduction of know- ledge " into systems as a " mere covering and palliating of ignorance, that men have used of a few observations on any COXCLUSIOXS. 497 subject to make a solemn and formal art, b}' filling it up with discourse and accommodating it with some circumstances and directions to practise " ; and he further notes, that " as young men when they knit and shape perfectly, do seldom grow to a further stature, so knowledge, while it is in aphorisms and in observations, it is in growth; but when it once is comprehended in exact methods, it may perchance be further polished and illustrated and accommodated for use and practice ; but it increaseth no more in bulk and substance." * When we review the absurd superstitions that have been connected with the so-called congenital malformations, and observe the process b}' which we have been led to the solution of the mystery in simple and intelligible laws, the furnishing of such a physiological standard for interpreting the apparent anomalies of birth, encourages us to persevere in trying to find the true teleological interpretation of whatever in nature may seem at first to be causeless and capricious. In the problems of pathology there are always two methods of investigation.f Firstly, morbid phenomena must be generalised in the direction of the vital forces concerned in their production ; secondly, morbid influences or causes must be contemplated, not in the multiformity of the outward world whence they originate, but in their relation to the living agent, whose excitability is the condition of their causativeness ; the living agent whose i^owers and functions they excite or depress, or whose organic material the}' modify. * "Advancement of Learning," 31, and " Interpretation of Nature," 18. t Simon, "Aims and Philosophic Method of Pathological Piesearch," London, 1847. 32 498 CHAPTER XY. The Factoes of the Insanities {Continued). Physiological Periods of Life — Infancy — Causes of Idiocy and Imbecility —Types of Infantile Mental Defect — Night-Terrors — Dreams — Nightmares — Somnambulism — Infantile Insanity — Causes — Heat — Fevers — Masturbation — Puberty — Adolescence — Puerperium — Menopause — Senescence — Bodily Affections as Factors — Genital — Urinary — Digestive— Circulatory — Respiratory — Other Diseases — Neuroses — Spinal — Sympathetic ■ — Cerebral — Intoxicants — Immediate Factors — Vaso-Motor — Vascular — Nutritional — Hughlings-Jackson's Scheme of Factors — Conclusions. THE FACTOPtS OF THE INSANITIES. In order to make our account of the aetiology of insanity fairly complete it is essential that we should devote our attention to the consideration of those affections of the body which either determine or are associated with morbid mental states. We cannot undertake to discuss in ' detail all these numerous relationships. It must suffice that we disciTSs the various questions from a general point of view, and note more particu- larly those bodily and mental perversions which are most commonly met with as associated conditions. The physiological periods of life which are most fraught with danger to an individiial are those of birth, infancy, puberty, pregnancy, the menopause, and senility. AVe now propose to study these periods somewhat in detail. FACTORS DURING INFANCY. 409 Infancy. — The various forms of idiocy and imbecility may arise from causes acting before birth, at birth, or subsequently. Of the causes acting before birth we have to note — in addition to those dependent on a neurotic inheritance of insanity, epilepsy, syphilis, alcoholism, tuberculosis, etc., — the liability of the mother to suffer from abnormal mental or physical condi- tions during gestation. The causes acting at birth may be, premature birth, difficult labour, instrumental delivery, accident, asphyxia neonatorum, or primogeniture. Those acting subse- quently to birth may be, infantile convulsions, epilepsy, cerebral affections, febrile disturbances, paralytic affections, sunstroke, nervous shock, or physical injury to the head.* Among the more important factors which determine mental defects or aberrations in the infant, we have to note the follow- ing structural abnormalities of the brain and spinal cord : — (1) Anenrep]ialus,'\ in which the vault of the cranium is absent, the base of the cranium being occupied by a mass of connective tissue and blood-vessels, formed from ingrowths of the pia mater; (2) Absence of the ']jrosenceplialon,\ in which there is found a rudimentary thalamcephalon, the cerebellum, pons, and medulla being reduced in size owing to the absence of develop- ment of the prosencephalic fibres ; (3) Cyclops, § in which there is an undivided anterior cerebral vesicle occupied by only one ventricle, and in some cases the presence of only a single optic nerve and a single eye. One case has been described, in which there was merely a superficial furrow between the frontal lobes. A tri-lobular brain, and a double brain of four hemispheres, have been recorded. The other abnormalities of the brain and spinal cord have been grouped as follows || : — * Shuttleworth and Fletcher Beach, " Tuke's Dictionary," p. 659. t " Encycloptedia of Diseases of Children," vol. iv. part II. p. 728. :;: Starr, " Journ. Nerv. and Ment. Diseases," July, 1886 ; Dana, ibid., Januarj', 1888. § Vide " Edin. Med. Journ.," vol. xxxii. No. 3 ; Hadlich, " Arch. f. Psych.," 1880, Bd. X. p. 97 ; Wille, ibid., 1880, Bd. x. p. 97 ; Heydenreich, " Virchow's Archiv.," iv. 1885, Bd. c. p. 24 ; " Internat. Monatschr. f. Anat. u. Phys., ' 1888, p. 11 ; also " Virchow's Archiv.," Bd. cvi. p. 390. II McNutt and Post, " Encyclopfedia of Diseases of Children," vol. iv. p. 730. 500 THE FACTORS OF THE INSANITIES. 1. Abnormalities accomjjanied Inj defects in the envelopes of the part : — {T^ncephcdocele. HydTencephalocele. Meningocele. ( Myelocele, (h) Bachischisis . . < Meningocele spinalis. \ 8pina Infida occidta. 2. Abnormalities in ivhicJo the envelopes are entire : — I Hydrocephalus. Microcephalus. Porencephaliis . Aberrant arrangement of fissures and convolutions. Agenesis of cortical elements, commis- sures, and associative tracts. The consideration of these structural abnormalities is of great interest, and at the hands of Spitzka,* Mills,! ^^^d Sachs,:!: the arrangement of convolutions and the degree of develop- ment of the nerve-elements, in connection Avith the brains of imbeciles and criminals, have received a certain amount of attention. We lack space, however, to give a more complete review of the subject. Of the various types of congenital and acquired imbecility which may be diagnosed during infancy, we have to note the following § : — 1. Congenital, in which the individual is usually of a low type, with a tendency to physical weakness, strabismus or nystagmus, a highly-arched or elongated palate ; also, automatic movements, contractures, or spastic rigidity. Such patients not infrequently slaver, and appear to be incapable of caring for themselves. Their special senses may be defect- ive or only partially developed, and there may be little or no power of attention or volition. * " American .Jouni. of Neur. and Psych.," 1882, p. 386. t " Journ. Xerv. and Ment. Dis.," Sept. and Oct. 1886. + Ihid., Sept. and Oct. 1887. § Vide Shuttleworth, " Brit. Med. Journ.," Jan. 30, 1886. CONGENITAL AND ACQUIRED FACTORS, 501 The types of congenital imbecility have been classified as follows : — (ft) Simple congenital, which include those forms without any obvious physical deformity of the head or limbs. The Mongol or Kalmuc idiot belongs to this class. A typical Mongol idiot, however, is nsnally of stunted growth and brachy- cephalic. His fingers and hands are short and dwarfed. Defective circulation, and inability to resist acute diseases, usually incapacitate them from attaining to adult age. (h) Microcephalic, in w^hich the brain has ceased to grow, due either to some internal cause or to the premature closure of the sutures of the skull. As a general rule, heads below 17 inches in circumference are held to be too small for ordinary intelligence. Vogt believes, that microcephaly is an instance of atavism ([\xe to the inheritance from some very remote ancestral ape. (c) Hydrocephalic, in which the fontanelle is raised : the head is globular, with the widest circumference at the temples, and occasionally a slight bulging above the super- ciliary ridges, (d) Scaphocephalic, in which the head is keel- shaped, (e) Paralytic, in which there is arrest of development of part of the brain, due to injury, disease, or apoplexy. In such cases the mental powers can sometimes be cultivated to a certain extent, but the physical development is locally arrested. Usually one hemisphere only is affected, (f) Cretinism, which may be sporadic or endemic. 2. The types of acquired imbecility are as follows : — (ft) Eclamjysic, in which there is arrest of development of the mental functions, due to the occurrence of convulsions soon after birth, and which have damaged the structm-e of the brain. (h) Epileptic, in which, as the result of frequent fits, the intellect becomes dull, and the individual becomes incapable of advancing intellectually, (c) Paralytic, in which the paralysis is accjuired at some period after birth. Some of the cases are due to the occurrence of fits, or to cerebral apoplexy, (d) Inflammatory is usually a sequel to some acute illness, such as measles, typhoid fever, whooping-cough, sunstroke, etc. The amount of impair- ment of the mental faculties depends in great part upon the amount of damage to the brain-tissues, (e) Hypertrophic, which may or may not be associated with rickets. Usually, the brain is not so large as in hydrocephalus. The head is somewhat 502 THE FACTORS OF THE INSANITIES. square, and bulges above the superciliary ridges. Hypertrophy- is said to differ from hydrocephalus in the fact, that in the former there is no elasticity over the late-closed fontanelle as in the latter. In hj^drocephalus the distance between the eyes is increased ; in hypertrophy this is not the case.* (/) Trau- matic, due to a fall or blow on the head. kSometimes the injury has caused the occurrence of fits, which serve to prevent mental improvement. (inal fluid l^e unimpeded, and that the blood itself be adequate in amount and efficient in quality. In heart disease any of the above conditions may be deficient, and, as a consequence, there may be impaired nutrition, access of poison to the cerebral cells, or even total destruction of the brain-tissue. Mickle* believes, that special forms of cardiac valvulai- lesions are attended by fairly-well defined mental symptoms. Mitral regurgitation is attended by some depression with * "Goulstonian Lectures," 1888. CARDIAC DISEASE. 513 delusions of suspicion and persecution ; not uncommonly the j^atients are morose and sullen. With mitral stenosis the patients are excitable and impulsive, discontented, querulous, and fr('<|uently have delusions as to ill-usage, or as to their food being poisoned. With aortic regurgitation there would appear to be associated restlessness and sleeplessness, together with misinterpretation of internal sensations, sometimes delu- sions of exaltation, and at times loquacity and general excite- ment. Aortic stenosis is sometimes attended by impulsiveness, violence, and delusions as to persecution and poison. When the aortic valve becomes atheromatous there is a tendency to rapid mental decay. When mitral and aortic diseases are asso- ciated there may be also a gross cerebral lesion, with dementia and degradation of the bodily functions generally. With hy])ertro]ihy and dilatation of the heart there may be depres- sion or delusions as to persecution. Degeneration of the cardiac muscle is sometimes attended with irritability, rest- lessness, and ideas of persecution. The relative frequency of the various forms of cardiac disease occurring in association with different mental mani- festations is a subject of interest, but we are unable to explain the nature of the mental disturbance solely from the considera- tion of the cardiac disease. Were the cardiac disease the sole cause of the mental disorder, the wards of general hospitals ought to pi'ovide us with innumerable data upon which to base our conclusions. Since no one individual reacts to circum- stances in precisely the same way as any other individual, it is impossible, without full consideration of the life-historj', habits, and mental characteristics, to do more than conjecture. as to the nature of the mental reaction which may occur in association witii any bodily disease. From a clinical point of view we know that, in an insane person, vague ideas of fear, sleepless- ness, and subaciite forms of excitement, are commonly associated with caidim- disease. The numerous investigations upon the character of the pulse in insanity have only taught us, that there may be low or higli tension, and that the variations bear some relationship to the general ])hysical condition of the patient. The blood has also been subjected to much analytical examination. We may say 88 514 THE FACTORS OF THE INSANITIES. briefly, that it may or may not be deficient in quantit}^ or quality according to the physical condition of the patient at the time of the examination. An excess of bile or uric acid may be associated with depression or irritability respectively ; but the condition of the serum, fibrin, and globules bears no constant relationship to the mental state. Deterioration of the blood maj' be attended by any form of mental disease ; or, conversely, mental disease may be associated with any form of blood deterioration. It is obvious, also, that poor blood is not neces- sarily associated with insanity. In general paralysis absence of rouleaux, and increase of the colourless blood-corpuscles at the expense of the red. have been noted, especially in the later stages ; but similar conditions are found in other degenerative diseases, and do not necessaril}', therefore, bear any obviously constant relationship to the mental symptoms. Hitherto, this line of research has not yielded much towards the solution of the main question — viz., the direct delation of the blood to the mind. The only conclusion at which we can arrive is. that in some instances blood-deterioration and mental diseases are asso- ciated, or possibly they are mutually causal factors ; but, at the same time, it must be remembered, that each condition is rela- tively more frequent by itself than in association with the other. Phthisis is regarded as bearing a fairly definite relationship to morbid mental states. Phthisical patients are liable to become insane, and, conversely, insane patients are liable to become phthisical. Beyond the characteristic hopefulness of phthisis, however, there is no definite or obvious clinical relationship. The irritabilit}- and the tendency to find griev- ances upon the slightest pretext are in no wise more commonly associated with phthisis than with other exhaustive diseases of the body. Idiots and imbeciles are particularly prone to become phthisical, and, according to Ireland, two-thirds of them die of it. Some authors believe, that there is a distinct form of phthisical insanity. This, however, is by no means satisfactorily established. Undoubtedly, mental diseases which are attended by bodily exhaustion and malnutrition predispose to the occurrence of phthisis. In such cases the mental symptoms obviously appear before the phthisis. Sometimes many of the symptoms of phthisis are absent when insanity is FEBRILE .\FFECTIOXS. 515 present, or the functional processes of the two diseases mav alternate. On the phj-sical side the svniptoms are usuall}' those of phthisis, and on the psychical side those commonly associated with exhaustive diseases. Other diseases of the respiratory system may cause such exhaustion of the bodily functions that insanity supervenes, or vice versa : or the symptoms, bodily and mental, may alternate. Fehrile Affections * — The occurrence of insanity as a com- plication of, or as a sequel to. acute febrile disease has long- been noted. The mental disorder may occur as the earliest symptom, but more commonly it appears during a later stage of the fever, especially during the period of convalescence. The intensity of the fever bears no constant relation in the produc- tion of insanity. Xasse classified the mental affections origin- ating in fever according as they are the immediate result of the fever itself, as they constitute a prolongation of the delirium when the fever has subsided, or as they arise during convales- cence. The specific infectious fevers, intermittent fevers, and long agues are apt to be followed by insanity. Erysipelas, articular rheumatism, acute angina, diphtheria, erythema nodosum, miliary roseola, purpura, febrile urticaria, guttural herpes, and other acute febrile diseases are also sometimes followed by insanity. There does not seem to be any definite relation between the different forms of insanity and the nature of the febrile disease. One point of clinical interest to be noted is, that after tvphoid. typhus, smallpox, scarlatina, cholera, diphtheria, influenza, or malaria there may be physical symjjtoms M'hich. ^\•hen associated with insanity, closely simulate general parah'sis of the insane. The general constitiitional disturbances and de- generation of the tissues of the bod}- (especially of the cerebro- spinal system), which occur in pellagra, are frequently attended by morbid mental states. These mental states, however, have nothing unusual or characteristic in their nature to distinguish them from those of other exhaustive diseases. Influenza has frequently proved itself to be a determining cause of insanity, and this more readily in individuals who are predisposed to neurosis. * Hyslop, " Diet, of Psycli. Med.,'' p. 985. 516 THE FACTORS OP THE INSANITIES. Syphilis may or ma}^ not cause insanit3^ Some individuals may have syphilophobia as a symptom without any actual syphilitic affection. Others may have contracted syphilis and break down mentally in consequence of dread of the results. Savage* describes the following relationships between syphilis and morbid mental states : — (1) Insane dread of syphilis ; (2) insane dread of results of syphilis ; (3) syphilitic fever, delirium, and mania ; (4) acute syphilis leading to mental decay ; (5) syphilitic cachexia and dyscrasia, and mental dis- order ; (6) sjqDhilitic neuritis (optic), with suspicion, or mania ; (7) syphilitic ulceration, disfigurement, and morbid self-con- sciousness ; (8) congenital s^^philis, cranial, sensory, or nerve- tissue defects ; (9) congenital syphilis, with epilepsy, or idiocj' : (10) infantile S3q:)hilis may be acquired. (11) Constitutional syphilis (a) vascular or fibrous ; (h) epilepsy ; (c) hemiplegia ; {(1) local palsies; (e) general paralj'sis, cerebral, spinal (spastic and tabetic), peripheral. (12) Locomotor ataxy (a) with insane crisis, (A) with insane interpretation of the ordinary symptoms. That S3q3hilitic affections of the nervous system may cause insanity is a statement which requires no justification. There is much difference of opinion, however, as to the part plaj^ed by syphilis in the production of general paralysis. Our experience in Bethlem leads us to believe, that more than half the general paralj'tics admitted to the hospital owe their disease to syphilitic factors. Savage believes, that at least seventy per cent, of his private cases of general paralysis have clear histories of constitutional syphilis. Clinically, we have also to note that syphilis sometimes gives rise to a pseudo-general paralysis m which, during the early stages, the symptoms may be identical with those of general paralysis ; but subsequently there is an arrest or protraction of the symptoms in the pseudo- form, so that the patient may live for many years. The syphilitic disease may manifest itself in lesions of the bones of the cranium, the membranes, blood-vessels, brain- substance, cerebral ner\'es, or of the organs of special sense. The skull bones may be absorbed owing to gummatous infiltra- tions, or small area^ of caries with exfoliation may occur. The dura mater and the pia arachnoid may be thickened and ■" •' Tuke's Dictionary," p. 125.3. EPILEPSY. 517 affected by various inflammatory deposits, or there may be gummata. The middle and inner coats of the arteries may show the characteristic endarteritis. Peri - arteritis and inflammatory deposits round the smaller arteries also occur. The brain-substance may be affected by means of an extension of the disease from the membranes, or as the result of deficient blood-supply. The nerve-structures of the cortex are apt to degenerate in proportion to the amount of overgrowth of the neuroglia substance. The cerebral nerves and the organs of special sense may be implicated symmetrically or otherwise. The nerve-fibres may become atrophied and fail to perform their functions. Diseases of the nervous system may be the predisposing or exciting factors of an attack of insanity. Epilepsy may depend upon general nervous instability, and this in turn may be due to cerebral lesions. It is important to remember that injury or disease which leads to insanity in one individual may lead to epilepsy in another. In neurotic families it is not uncommon to find one child epileptic and another insane. The children of neurotic parents are particularly liable to suffer from convul- sions which may become epileptic in character, and when habitual, the mental development is apt to be arrested. Morbid mental symptoms may precede or follow an epileptic fit. When they precede the fit they may be in the form of sensory perversions (illusions or hallucinations), delusions, or maniacal outbreaks : when they follow the fit they may appear as confusion, melancholia, irritability, suspicion, hallu- cinations, false accusation, moral perversion, and, not uncom- monly, mania, or epileptic furor, with suicidal or homicidal impulses. When there is imperfect loss of consciousness with automatic action, the condition is termed mashed epilepsy. The patient does not fall down, and in some cases actions are performed automatically. Sometimes violent emotion, with violent or vicious acts, take the place of the automatic act. Jacksonian epileptic attacks differ from ordinary epileptic attacks in that the spasm progresses in a definite direction. Consciousness may be lost late in the paroxysm, and temporary- paralysis or aphasia may follow the seizures. This variety is mostly due to cortical irritative or degenerative lesions. 518 THE FACTORS OF THE INSANITIES. Epilepsy includes all paroxysmal sensori-motor discharging lesions of the nervous system. The affection may involve anj" or all parts of the cereljro-spinal system — i.e., the " lowest, middle, or highest levels " of Hughlings-Jackson. Nutritive molecular changes in parts of the nervous system are apt to cause discharging lesions, which necessarily vary according to the importance and complexity of the functional provinces involved. Discharging lesions involving the highest centres throw the organ of the mind more or less out of gear. In the severe forms of ej)ilepsy the discharging lesion may begin in the cerebral cortex and extend to the lower levels of evolution. Jn minor ej)ilepsies, on the other hand, some part or parts of the anatomical substratum of thought, may alone be affected, so that the temporary defects of consciousness are the sole manifestations. The analogy between what happens in epileps}^ and in maniacal and uncontrolled mentation is thought hy some authors to be well-nigh complete. They assume, that in both conditions the mental symptoms are due. to excessive cerebra- tion. Of this view we shall, however, have to speak again, so we now return to the consideration of other neuroses which may be factors in the causation of insanit}*. Hysteria has its physical basis in an (apparently) functional disorder of an}- or all parts of the cerebro-spinal system. The symptoms vary according to the functional provinces mainly involved. The mental characteristics are usually manifested in paroxysms with or without uncontrollable physical sym- ptoms. By some authors it is assumed, that hysteria is an affection of functional provinces which are often actuallj^ controllable hj the influence of other and higher centres. This, however, is an hypothesis which is scarcely susceptible of veri- fication. The bodily and mental causes which lead to hysteria may also lead to insanity ; or insanity?' may supervene upon hysteria. There is no hard and fast line of demarcation between h^'steria and mania : the one shades imperceptibly into the other. In l)oth there may be sensory or motor disturbances with inorbid perception and misinterpretation of their import. Chorea is commonly attended b}^ mental hebetude, in- attention, loss of memory, and hallucinations of sight of an un]:)leasant nature. The mental sjanptoms may precede the SPINAL DISEASES. 519 actual choreic paroxysms. Choreic insanity may be of any type, and it exhibits nothing that is characteristic. It may appear in children, in pregnant women, or in old age. Myxoedema is usually followed by insanity. During the earlier stages of the disease there is languor, indifference, and impaired memory. Sometimes there is irritability with hallucinations or delusions. The insane sjanptoms may be those of acute or chronic mania, melancholia with suspicion and self-accusation, or dementia. The insanity may be due either to morbid self-consciousness as to their changed appear- ance, or to the morbid state of the vaso-motor nerves which directly affect the cerebrum. Whitwell* has noted the occurrence of inflated globose and curiously distorted nuclei, vacuolated in almost every conceivable way, in the cells of the third and fovirth layers of the cerebral cortex. JExophthahnic fiottre is supposed to be closely allied to the neuroses. Sometimes lesions of the sympathetic ganglia have been observed. The pathology of the affection is at present undecided. It has been regarded in turn as a scrofulous d^^scrasia, a neurosis of the sympathetic, a disease of psychical origin, and as a paralysis of the vaso-motor centres and cervical ganglia. The disease is not uncommonly associated with mental symptoms. It may occur in association with melan- cholia, acute mania, delusional insanity, and even general paralysis. The exophthalmic symptoms may occur sjm- chronously with the mental attack, and they may return with each recurrence of the insanity. It is more frequent in women than in men. In one case admitted to Bethlem the mental symptoms arose in connection with the change in aspect of the patient : painful self-consciousness gradually changed to ideas of persecution. Another case began with exaltation and excitement : two others were first depressed, then melan- cholic, with refusal of food, impulsive violence, and dirty habits. Exophthalmic goitre has been observed as occurring temporarily from sudden shock. Sometimes it is associated with epilepsy, paralytic affections, hemiantesthesia, or even with aphasia. Spinal afedions may precede, occur in connection with, be symptomatic of, or follow, various forms of mental disease. * "Brit. Med. Journ.,"' Feb. 27, 1892. 520 THE FACTORS OF THE INSANITIES. Insanity withont paralysis is not attended by spinal changes. Traumatisms, slow compressing lesions, cornnal or columnar lesions, indiscriminate lesions, or functional defects of the spinal cord ma}' be associated with insane symptoms of a temporary nature, or they may be associated with cerebral lesions and progressive mental deterioration. To describe the various spinal diseases which may be associated with insanity would necessitate an account of all the extra and intra-medullary lesions dependent upon recog- nisable organic causes, and also of the various intrinsic or functional defects, such as the toxic spinal paralyses, inter- mittent, hysterical, ideational, and reflex paraplegias, etc. It must suffice for us to remember, that the spinal lesions may be primary or secondary to cerebral lesions. Beyond this general statement we cannot venture. There is no more definite relationship between system lesions of the spinal cord and insanity than there is between lesions of other systems and the mind. Every variety of spinal disease may occur in the insane, and every variety of spinal disease may occur without insanity. There are no special mental symptoms of spinal lesions, and there are no special spinal symptoms of mental diseases. In general paralysis we meet with nearly every variety of spinal degeneration, but there is no constancy in the relationship. Affections of the sym.jiathetic are but imperfectly understood. The intimate relationship between all parts of the cerebral cortex and the exquisite mutual dependence of the various parts of the nervous system — cerebral, spinal, and sympathetic — on each other, render this subject one of extreme intricacy and difficulty. The sympathetic system is undoubtedly affected in many morbid cerebral states. Whether the affection is de- veloped as a reflex irritation, or whether the sympathetic system possesses a special pathology of its o\^-n and acts as a primary factor in determining the morbid cerebral state, we are unable to decide. The intimate relations existing between headache, insomnia, epileps}^, or other cerebral affections, and the regula- tion of the vascular tone through the sympathetic, lead one to suppose that possibly the sympathetic plays a ver}^ jDrominent part in the production of many changes of structure and INTOXICANTS. 521 lesions of nutrition in the cerebrum. It is generally believed, that the influence of the sympathetic is brought about secondarily by reflex irritation from some other organ in the body. Cerebral affections have already been in part considered ; but in order to render the physiological part of our subject more complete it is necessary that we should briefly enumerate some of the causes of paralyses of encephalic origin. Among these causes we have to note, traumatisms, meningeal, cerebral and cerebellar haemorrhages, occlusions of vessels by thrombosis or embolism, tiimours of the brain and its meninges {e.g.. tubercle, scrofula, cancer, giiomata, sarcomata, myxomata, tumours of the pituitary body, and exostoses), abscesses within the cranium, meningo-encephalitis, disseminated sclerosis, aneurysms, hydatid cysts, cysticerci, simple cysts, and congenital or eavlj infantile pathological states of the brain. The signs and symptoms of these various affections do not form part of our subject ; and as we have already discussed their value from the point of view of localisation of mental phenomena, we, therefore, now pass to the consideration of those intoxicants which act as factors in the production of mental diseases. Intoxicants. — Alcohol. — The effects of alcohol upon the exquisite structures of the brain, and consequently upon the mental faculties which these structures subserve, have been so widely investigated that the subject need only be briefly referred to here. The derangements due to alcohol may be mainly sensory, motor, or intellectual. Alcohol may produce a temporary disturbance of the intellect by means of its direct poisoning influence on the brain, or it may cause structural alterations of the brain which are characterised by progressive weakening of the mental faculties and finally dementia. The symptoms of direct poisoning and slow decay of the brain and mind need not be dwelt upon. Alcohol may be absorbed through the serous, mucous, or respiratory surfaces, and may leave the system unchanged. It produces changes in the blood which lead to profound nutri- tional disturbances in the brain and sympathetic system. The action of alcohol upon the cerebrum is so wide-spread and so variable that any mental symptom may appear. Bevan Lewis 522 THE FACTORS OF THE INSANITIES. says, "The symptoms of implication of special cerebral territories too often dovetail and overlap for any trustworthy clinical classification to be adopted ; and still more frequently if the history be one of progressive invasion of one territory after another. The more characteristic forms, however, under which cerebral alcoholism presents itself to our notice in asylums for the insane, are the following: — (1) Pureh^ sensorial type — (a) common sensibility ; (A) visceral ; (c) special. (2) Primary amnesic forms. (3) Premature senility, especially implicating motor areas of cortex. (4) Delusional forms with vascular lesions in basal ganglia and medullated tracts of the cerebrum. (5) Motorial types." Andriezen* believes, that while cases of the extensive and generalised type of alcoholic insanity are by no means rare, the majority of the alcoholic insane are those who belong to the other class in which the main morbid stress and evolution of the symptoms develop in this or that " intensive and specialised way." He also believes, that changes occur in the anatomico- physiological connections between the neurons. '• Change of a very striking and unmistakable character occurs in the ultimate protoi^lasmic expansions and • contact-granules ' situated upon them on the one hand, and in the ultimate naked fibrils (collaterals and terminals) which everywhere come into relation with such protoplasmic termini and granules on the other. Beginning with a softening and swelling of these contact granules, and also of the protoplasmic twigs on ^^•llich they are situated, the earliest noticeable changes are a coales- cence of these into small irregular ' composites ' of such, recotiiiisable hei*e and there as a local coarseness. As the changes progress in coarseness and extent, they can now be more easily recognised as commencing moniliform swellings along the course of the terminal protoplasmic twigs." These earh' dynamical changes in the field of conjunction are held to represent, on the psychical side, the diminished capacity of the neurons to be excitable to presentative sensorial stimulations : the diminished permeability in the pathA\'ays of nerve-currents issuino- from one neuron by its nervous processes and its terminals to another neuron in the cortical area, having its * "Brain," p. 666, 1894. INTOXICANTS. 528 psychical countei'part a slowness in the arousing of associated images, and delay of reaction time. These observations are of great interest to cerebral pathology, and did the associated mental sjnnptoms present any uniformity they would be valuable to mental physiology. It is more particularly in the early stages of alcoholism that all kinds of mental manifestations are possible, and swellings of the " contact granules " may serve to explain delay in the passage of nerve-currents, and therefore also delay in the physiological manifestations : but these swellings afford us no explanation as to the origin of the hallucinations or the delusions so commonly met with in the alcoholic insane. They may possibly serve to throw some light upon the amnesic defects as manifested in the slowness in arousing associated images, but they do not account for the positive mental affections which are characterised by emotional or intellectual perversions. Lesions of the spinal cord uiay serve to delay sensation or reflex action, and the description of such lesions might suffice to account for the dela}'. Such a description, however, would furnish us with no explanation of the ultimate physiological factors associated with the mentation. Similarl}*, lesions of the '• fields of conjunction '" in the cortex afford us no ultimate data for the explanation of morbid psjxhical manifestations. Here, as in other instances, we must have recourse to physiological hj^pothesis as to the ultimate material elements concerned with mind, and by so doing we can onlj- speculate about the un- known and unknowable. The most that pathology has done in this instance is to partly verify the opinion as to the co- existence in time between the events, the physical and mental series. Lead poisoning is not infrequently . attended by symptoms which somewhat resemble those of general paralysis. Saturnine cases may exhibit' symptoms of mania, melancholia, dementia, or pseudo-general paratysis. Kegis notes the frequencj^ of nightmares, terrifying hallucinations, and ideas of persecution with, also, very marked tremor of the limbs. The pseudo- general paralytic symptoms generall}^ appear after the delirious symptoms of the lead intoxication have passed off. Under appropriate treatment the disease proves itself to be essentiall_Y 524 THE FACTORS OF TEIE INSANITIES. curable. The presence of neuralgic pains, convulsions, cramps, headache, delirium, stupor, amaurosis, paralysis of the extensor muscles of the wrist, ansesthesia of the affected part, fatty de- generation of the muscles, and the other special symptoms of lead poisoning render a diagnosis possible. The lead appears to act primarily on the muscles, then on the nerves, and lastly on the nerve-centres. Morphinomania resembles in its effects the symptoms of the other toxic insanities. The abuse of morphia is usually attended by well-known mental and physical perversions, which sooner or later become symptomatic of cerebral degeneration. Sudden withdrawal of the drug is also apt to be attended by a characteristic train of symptoms which may range from mere irritability to maniacal delirium. The fact that morphia produces an exaltation of the mental faculties, a greater brilliancy of the imagination, and an aptitude for study, has proved itself to be the cause of the mental ruin of no few individuals. Other toxic agents, such as belladonna, hyoscyamus. stra- monium, absinth, ether, chloroform, chloral, cocaine, haschisch, nicotine, etc., when taken in large quantities are apt to cause cerebral disorders and various psychical symptoms, but space will not allow of their consideration. Immediate Factors.— Hitherto we have devoted our attention to the consideration of bodily factors which act upon the brain either directly or indirectly ; it now remains for us to refer to some of the more immediate brain factors them- selves. The mechanism of cortical functional hypertemia is, as we have already seen, only imperfectly determined, and we do not as yet know how functional hypereemia is im- mediately brought about. The theory, that the special func- tional activities concerned with mental events are attended by a special functional hypergemia is supported upon the crudest and most slender grounds. We are told that the cortex of a man's brain bulges through a hole in his skull when a mental stimulus is applied,* and that with the occurrence of activities within definite brain-areas there is, or ought to be, a sudden rapid change of blood-supply to those areas, t * " Pathology " — " Tuke's Dictionary," p. 896. t Meynert, " Psychiatry," p. 214. FUNCTIONAL HYPEREMIA. 525 Let ITS for a moment consider these suppositions a little more closely. It is assumed, that in the ordinary course of psychical events the immediate substratum of physical activity rests somewhere within one or more of the exceedingly minute cortical cells, or in the ramifications of its processes. If now we take for illustration an "idea" — which presumably derives its component parts through association paths from several areas — it seems reasonable to assume, that with the activities within these different areas there is a corresponding functional hypertemia. This necessitates a rapid change of circulation in several areas at once. In fact, if the theorj^ is to be complete, the hyperaemia must follow the mind through all its variations. This may be the case for all we know to the contrary ; but it is scarcely credible that any psychical act taking place, presumably within a structure so minute as a nerve-fibril, should also determine a hyper£emia which would make the cortex of the brain bulge through a hole in the skull. Undoubtedlj^, the vascular suppl}- ( »f the brain is arranged so as to favour the rapid production of hyperEemia ; but surely the extreme rapidity of thought is not entirely and immediately dependent upon a mechanism which lumbers along in its wake, causing here and there a turgescence or bulging of the whole structures ? That the finely molecular activities of the nerve-substance require such a vastly disproportionate blood-supply is scarcely credible. kSuch a relationship between the visible hypergemia and the molecular activity would appear to be proportionate to the relationship between an Atlantic wave and the activities in coccoliths and coccospheres embedded in the Bathybius of the sea-bottom. Interference with the nutrition of the nervous tissues, it long continued, is followed by a series of changes in those tissues. In idiopathic brain disorders there is supposed to be primarily an abnormal supply of blood to the brain. This may pass on to a sub-inflammatory condition, in which more leucocytes are deposited than in the normal state between the adventitia and muscular coat, or there may be proliferation of the connective tissue cells of the vessel. Should these leucocytes and connective tissue cells break down, the debris occupies the 526 THE FACTORS OF THE INSANITIES. perivascular spaces, and thereby implicates the lymphatic cir- culation. Eetention of the waste products tends to affect the functional integrity of the nerve-cells and of their processes and fibres. The actual degeneration of the cell protoplasm is supposed to be due to toxic action from within and deprivation of proper nutriment from without. The pathological appearances of inflammatory action in the skull, membranes, and blood-vessels are fully described by Sevan Lewis, Batty Tuke, Sims Woodhead, and others. The neuroglia and connective tissue cells have also been very carefully described by these authors. Finally, the numerous and elaborate investigations upon the pathology of the nerve- cells have furnished us with so much valuable material that a mere dilettante consideration of them would only prove unsatis- factory to the student, and hardly do justice to the importance of the subject. We propose, therefore, merely to consider the factors of the insanities in so far as they are dissolutions,' or reversals of evolution. To Hughlings- Jackson * we are indebted for a forcible conception as to the pathogenesis of maladies of the nervous s^^stem. He assumes, that in every insanity there is morbid affection of more or less of the highest cerebral centres, or, synonymously, of the highest level of evolution of the cerebral sub-sj^stem, or, again synonymously, of the anatomical substrata or phj^sical basis of consciousness. There may be discoverable disease destructive of nervous elements, or there may be loss of function from some undiscovered pathological process inferred from symptoms. In every insanity more or less of the highest cerebral mechanism is out of function, temporarily or permanently, from some pathological process whatever it may be. In studjdng the insanities as dissolutions we have to take into account not only the depths of dissolution of the highest cerebral centres, but also the evolution going on in the undamaged remainder of them — the mentation remain- ing possible when various centres have been mutilated in different degrees. * " Factors of the Insanities "' — '• Medical Press and Circular," Dec. 9, 1S74 ; ibid., Aug. 30, 1S93 ; ibiiL, June 13, 1S9-1 ; "Transactions Ophthalmic Soc, " vol. vi. • . PATHOGENESIS. . 527 In every I'orm of insanity (dementia excepted) there is a double symptomatic condition — viz., a negative and a positive condition. The negative is dne to disease (negative lesion) ; whilst the positive is the outcome of activities of the healthy structures remaining. Disease, therefore, only causes the physical condition corresponding to the negative mental element. The positive symptoms vary inverselj* with the depth or extent of the negative lesion. For illustration, Hughlings-Jackson takes the case of a general paralytic who believes he is Emperor of Europe. " The delusion arises during activity of perfectly healthy nervous arrangements, presumably those of the posterior lobes and those left intact of the anterior." The disease of the anterior lobes he regards as responsible for the patient's not knowing that he is X.Y., a clerk in the city. This illustration we believe to be unfor- tunate, inasmuch as general paralytics at one moment may state that they are kings or emperors, but at the same time they do practically recognise that they are X.Y. Similarly, general paralytics construct schemes for the distribution of fabulous wealth, but immediately after^^•ards beg for tobacco, and tell you, with perfect accuracy, that they possess only a few pounds sterling, or that they are bankrupt. Moreover, they almost invariably ans^^'er to their names (especially during the early stages), and make a sharp distinction between their real and ideal existence. This, however, does not really interfere with the validity of the hypothesis. Illusions, delusions, extravagant conduct, and abnormal emotional states in an insane person may signify evolution, and not dissolution. The positive mental states are held to imj.)ly the coexistence of negative mental states, defective perception, less reasoning po^^'er, less adaptation to present surround- ings, and absence of the finest emotions. The examples given are, («) any illusion implies, that a thing is not recognised as it would have been before the insanity, and this means, that there is a coexisting negative element ; (1)) any delusion implies, that the patient does not believe as he would have done iDefore he underwent dissolution, and this means, that there is a co- existing negative mental element. Whilst admitting the difficulties in demonstrating the 528 THE FACTORS OF THE INSANITIES. physical nature of the negative lesions, we agree with Conolly, who defined insanity from the ps^'^chical standpoint as " an impairment of one or more of the faculties of the mind, accom- panied with, or inducing, a defect in the comparing faculty/" The psychical elements of the comparing faculty are derived from experience. Hence, the negative lesion would in reality consist in the deprivation of the individual of some part of his experience, and this (from the negative point of view) would mean merely a defective or perverted memory. The negative lesion would, therefore, imply an interference with the material residues of experience. But this alone does not explain the nature of the positive symptoms. In popular language, the fact, that one batsman "retires hurt" from the cricket field, does not necessitate "tall" scoring of the undamaged remainder. Similarly with the general paralvtic, the existence of a negative lesion does not account for the exaltation of his ideas and his delusions of grandeur. Undoubtedly, the exaltation and the delusions are the work of the undamaged remainder, but this is no explanation of how they originate. In conclusion, we may state, that hitherto brain pathology has only served to demonstrate, (1) that part or parts of the complex process of our mental experience may be, by the existence of negative lesions, rendered inert or incapable of revival in consciousness. (2) That mental and physical pheno- mena do bear time relationship to each other ; perversions of the latter are in some cases attended by altered mental time reactions (as compared with normal psychical reactions). (3) AVe have no pJij/sioloijical data which give the faintest solution to the probleni as to hoir the positive activities of the mind, both normal and morbid, come to exhibit such endless diversities and infinitely varied relations. 529 APPEXDIX A. HYPNOTISM. The phenomena of hypnosis, in spite of having been sub- jected to scientific treatment, are still very obscure. The observed facts in cases of hypnosis consist of various physio- logical and psychological manifestations which are regarded as causallv connected with each other. Before entering, however, upon any question of their causal relations, it is necessary that \\e should briefly review some of the more important factr; observed on the physical and mental sides respectively. Mesmer (1734) first studied artificially-induced sleep. He attributed the effects to the action of the heavenly bodies, and " animal magnetism " was regarded as the special agency of the phenomena. Deleuze (1825) believed, that a magnetic influence (magnetic fluid) belonging to the vital principle passed from one person to another. Braid (1842) first attributed the phenomena to the laws of nerve-action. Since then. Charcot, Lu}-s, Doumontpallier, Binet, Fere, Liebeault, Bernheim, Forel, Moll, Dessoir, Sperling, Preyer, Baierlacher, Tuke, Bramwell, and others have contributed man}' observations which throw some light upon the subject. Methods of inducincj hyjpnotic sleep. — (1) Braid made the sub- ject fix his eyes on a bright object placed a little above the eyes opposite the middle line of the forehead, so that visual fatigue quickh' followed, the eyes being directed in convergent strabismus. (2) Lasegue pressed lightly upon the eyeballs with his fingers. (3) Pitres pressed upon special regions of the body (zones hxjijnogenes). (4) Monotonous sensory impres- sions produced by passes, etc., will induce the Iwpnotic state. 34 530 APPENDIX A. (5) By the ps^ycliological principle of suggestion. (6) Hj combinations of any of these methods. Operators vary in their power of inducing hypnotic sleep. Subjects also vary in the extent to which they can be hy]:)no- tised. Children under three or four years of age are difficult to hypnotise. The power of attention, of concentrating the con- sciousness upon the matter in cjuestion, renders a person more susceptible to hypnotism. Hysterical individuals are readily hypnotised. Idiots and imbeciles are unusually hard to hypno- tise. Similarly, insane persons are often difficult to affect in this way. Hitherto we have had (in England) little success in hypnotising insane patients. The English race does not appear to be very susce^rtible to hypnotic suggestion. Robertson* tried to induce hypnotic sleep in some insane patients at Morningside Asjdum, and he met with a certain amount of success. Our experience at Bethlem, however, has not proved so satisfactory. Drs. Percy Smith t and A. T. Myers found, that of twenty-one cases in which h^'pnotic suggestion was tried, only two were certainly hypnotised. In one case, hoM'ever, the suggestions made were not acted upon ; and in the other, although sug- gestions seemed at first to be in a very small degree successful, the effect, instead of increasing, diminished rather rapidly. Where any improvement was noticeable in the other cases, the results gained were attributable more to the large amount of personal attention devoted to each case than to any hj'pnotic influence. In order to awaken the subjects, it is customary to blow on their ej'elicls, or to rouse them in some vigorous manner. Symptoms of the liypnotic state. — The different phenomena have been divided by Charcot, and with the approval of Richer, Tamburini. and Seppili, into three fundamental types- -the cataleptic, the lethargic, and the somnamlmlistic. In the cata- leptic state the limbs retain the positions in which they are placed for a considerable time, and without effort. In the lethargic state the subject is insensible to the most painful stimiTli; the muscles which are relaxed are found to possess the power of contracting in a definite way under gentle * " Journ. Ment. Science," Jan. 1803. t I^id-, April, 1890. HYPNOTIS]^!. 531 mechanical applications. His intelligence seems to be abolished, and he does not respond to Cjuestions or react to suggestions, although he may realise them when he awakes. The phenome- non of neuro-muscular hyper-excitability proves itself to be the most interesting feature of the lethargic state. Charcot has demonstrated, that if in the subjects of la grande hysterie one compresses a superficial nerve, there follows a contraction of the muscle it supplies. This contraction is sometimes A^ery intense ; the muscles become rigid and stiff, and would be torn sooner than bend. In order to cause this rigidity to disappear, pressure is made upon the antagonistic muscles of the contracted ones.* The somnambulistic state can be induced by rubbing the vertex of a person in the lethargic state. The explanation of this is unknown. The remarkable neuro-muscular excita- bility is retained, but in a somewhat transformed state. According to Charcot and Gilles de la Tourette, it is no longer by hard pressure or friction of the muscles or compressing the nerves that it is brought about; it is, on the contrary, a simple, superficial, purely cutaneous stimulation which makes the underlying muscles contract. These observers state, that lightly pressing anything over the skin — the movement of the stratum of surrounding air — is sufficient to produce this effect. The mental condition during hi/pnosis is very varied. Sub- jectively considered, the experiences as to sensation, concep- tion, memory, and volition are of great interest. In previous pages we have discussed the relationship of hypnosis to memory (p. 349) and to volition (p. 424) ; it now remains, therefore, for us to give a brief account of sensations peculiar to it. Except in the early stages of hypnosis, there is usualh^ insensitiveness to pain. At the suggestion of the operator, however, it is possible to produce hyper-algesia. Ordinary tactile sensibility may re- main unaffected. The sense of smell ma}^ be absent, so that strong ammonia or pepper produces 210 reaction ; or there mav be hyperesthesia, and a vastly heightened sensibility of the olfactory nerve. Visual sensations are partial!}' affected in the early stages : in the later states the sense of sight may become preternaturally acute. There may be anaesthesia or hyperaesthesia of the sense of hearing. "Sometimes the subject * " Hypnotism "' — " Tuke's Dictionary,"' p. 608. 532 APPENDIX A. liears what is said to him bj^ the operator and by no one else. Taste is generally suspended, or, by suggestion, the subject imagines various tastes. Consciousness, objectively considered, may appear to be present and normal ; or there may be an abnormal susceptibility to psychical impressions. In the deep stages of hypnotism, however, the mind is much more markedly obedient to the suggestions of the operator. Some individuals when hypno- tised have the peculiar experience that they exist in duplicate. The one self is fully aware of what the other self is doing. This condition of duplicate consciousness is not uncommon in insane individuals. Hack Tuke* recorded the case of a patient several years ago in Bethlem Hospital, who, having lost himself — i.e., the self he was most familiar with — used to seek for himself under the bed. Hack Tuke believed, that the explana- tion of this division of consciousness was to be sought in the relation between the two halves of the brain, or between different centres in the entire cortex. One patient now in Bethlem used to say that his body did not belong to him, and complained bitterlv of the false position in which he was placed by an apparatus which was no part of himself. Such instances are not uncommon, but their phj'siological explana- tion is still a matter of conjecture. Suggestion. — As we have already said, the susceptibility to outside suggestions is one of the most noticeable features of the hypnotic state. Some obseiwers maintain, that the hypno- tised subject is at the mercy of everj^ suggestion, however absurd, and every crotchet, however wild and impractical. This, however, is not strictly true. The hypnotised subject is not necessarily always passive ; or, as Charcot says, " the sub- ject's credulity has its limits." Moreover, it has been found im- possible to make a subject commit an actual crime. A state of ecstasy can be induced by suggestion. Hallucinations and delusions are readily induced, and they may persist for some time after the subject is awake. Theories as to the hypnotic state ; (1) Theory of animal magnetism is now almost entirely given up, or, at any rate, scarcely ever referred to. (2) Theory of neurosis. Charcot and * " Sleep Walking and Hypnotism," p. 82. H YPNOTISM. 533 his colleagues at the Salpetriere maintain, that hypnotism is a neurotic manifestation which has been evolved, in a vast majority of cases, on a soil prepared by hysteria, with which it has many points in common. They also believe, that " sugges- tion" is an important element, but that it is not more im- portant than that which must be assigned to somatic phenomena. They argue, that although the psychical phenomena are sus- ceptible of being stimulated, the same cannot be said of the physical ones which are completely independent of the will of the subject in the hypnotic state. (3) The theory of suggestion denies the neurosis theory. It assumes, that the bodily sym- ptoms are the result of expectation' and training. In proof of this we have the fact, that all the neurotic manifestations may be induced by suggestion. Man}^ of the physical symptoms are due to the methods employed at the Salpetriere. Simple verbal suggestion, as employed at Nancy, is but seldom attended by any of the classical lethargic, cataleptic, or som- nambulistic states, except when induced by the influence of the operator. Although the theory of suggestion has at the present day the greatest number of supporters, we must not forget that the psychical factor " suggestion " does not explain the occurrence of the extraordinary bodily states, or of the subject's increased susceptibility to the suggestions. We agree with Ladd,* that the principle of suggestion is definitely a ■psychological- principle, and nothing else ; but we cannot say, that the psychological principle of suggestion is explanatory of any of the physical manifestations. The phenomena of the hypnotic state are both bodily and mental. No j)^ychological principle can account for any phj^sical state, and no bodily state can account for the psychical phenomena. The suggestion theory is regarded as satisfactory when it refers to psychical phenomena, although even there it does not explain the increased , susceptibility to suggestion. Or, as Professor James t j^^stly remarks, " the suggestion-theory may therefore be approved as correct, pro- vided we grant the trance-state as its pre-rec{uisite. The three states of Charcot, the strange reflexes of Heidenhain, and all " " Philosophy of Mind," p. 277. t " Principles of Psychology," vol. ii. p. 601. 534 APPENDIX A. the other bodily phenomena which have been called direct con- secjuences of the trance-state itself, are not such. The_v are products of suggestion, the trance-state having no particulai- outward symptoms of its own ; but without the trance-state there, those particular suggestions could never have been suc- cessfully made." Post-hypnotic sii/irjestions are those suggestions given to a subject during the hypnotic state with the intention of making the effects last in the waking state. The therapeutic bearings of hypnotism are manifold. Among the sane, the condition has been utilised to correct morbid habits and ci'avings. Some individuals have acquired considerable talent in special direc- tions by the aid of hypnotism. Thus, one person who suffered from nervousness and a certain amount of hesitancy in his speech was enabled to overcome both defects by post-hypnotic suggestion. He now displays considerable talent as a public speaker. Among the insane, it has been employed, as a sleep producer, as a sedative in excitement, to dispel fieeting delusional states and the minor psychoses, to overcome morbid resistance of patients, and as a substitute for mechanical restraint.* * Robertson, •' Journ. Ment. Science," p. 11, 1893. ooo APPENDIX B. PSYCHO-PHYSICS. Experimental psychology has as its aim the investigation of the general laws ^^•ith regard to the relation of processes of stimulation and sensation : it also includes the consideration of the processes which intervene between stimulation on the one hand and the complex processes of mental action on the other. In practical psycho-iDhysics attention has lieen more par- ticularly directed to the cpiestions of absolute and compara- tive sensibilit}'. The methods whereby stimuli are measured in relation to sense-impressions are, according to Fechner*: — (1) The method of ascerfaiiiinr/ differences of sensation, vliich are just distingiiishahle. This may be done — aj., by comparing the difference between two weights : if the difference be great, it is easily distinguished ; if not great enough, it will with difficult}^ be distinguished, or perhaps not at all. The method con- sists in finding that difference which just becomes appreciable, and this difference is reciprocal to the sensibility — i.e., if the appreciable difference is great, the sensibilit}^ is small, and vice versa. (2) The method of rir/ht and v-ronrf cases. This con- sists in testing the sensibility — e.g., by weights or light, constantly varjdng the amount of the former and the intensity of the latter. Cases in which the difference is coi'rectly appre- ciated are called " right cases *' ; those in which it is not recognised or appreciated are called "wrong cases." From these results is ascertained the mean difference, which, as before, is reciprocal to the sensibility. The method yields very good results, but a considerable number of observations * " Elemente der Psychophysik," 1889. 536 APPENDIX B. must be made. (3) The method of ascertainintj the mean error. It consists — e.(j., in trying to find from a number of weights one ■\^■hich is equal to a given weight previously determined, or to draw a line equal to a given line. The difference between the actual weight or line, and those erroneously chosen or drawn by the person malving the experiment, as being equal to the former, serves to determine the mean error, which again is reciprocal to the sensibility.* Mental operations are regarded as measurable quantitatively as to their degree, duration, and number. By degree is meant the intensity, vividness, and, according to some authors, the distinctness of the impression or idea. (The amount of con- scious effort — att(^ntion — involved is also taken into account.) By duration is meant the length of time involved in sensation, perception, ideation, sequences of ideas, memory, etc. The duration of mental operations is rendered susceptible to mea- surement by means of external arrangements. By nurnlier is meant the stages or steps involved in mental operations ; or the estimation of the number of operations involved in a sequence of ideas or train of thought. The various psijcho-pliysical lines of investiijation are as follows, after excluding all distractions: — (1) Test the discriminative sensibility of the skin with compasses, or by the aesthesiometer. (2) Test the sense of locality by touching different parts of the body. (3) Test the temperature sense as to the discrimination of differences at various regions. (4) Test the sensibility to heat and cold by applying metal points suitably warmed or cooled. (5) Test the discriminative power of motion by cb'awing a point up or down the skin of a limb, to determine whether the direction can be recognised. (6) Test the pressure sense by placing weights successively on the same spot, the patient to detect the difference between any pair of weights. With regard to the senses of sight, hearing, taste, smell, etc., it is unnecessary to repeat the enumeration of the various data which have to be determined. Enough has already been said in regard to them when "\^'e discussed sensations and their perversions. * See also Wundt, " Grundziige der Physiologischen Psychologie "" ; and Miiller, " Bibliothek f iir AVissenscliaft und Litteratur," vol. xxiii. PSiCHO-PHYSICS. 537 Reaction time is the time ^^•llicll elapses between the appli- cation of a stimulus and a conscious reaction. The psychical process involves a greater length of time than does a simple reflex act. Keaction time is usually measured by causing the person experimented on to indicate by means of an electric signal the moment when the stimulus is applied. The reaction time is supposed to consist of the following events : — (1) The duration of the perception — i.e., when we become conscious of the impi-ession. (2) The duration of the time required to direct the attention to the impression — i.e., the duration of appercep- tion. And (3) the duration of the voluntary impulse, together with (4) the time required for conducting the impulse in the afferent nerves to the centre ; and (5) the time for the impulse to travel outwards in the motor nerves.* There is much difference of opinion as to the mental processes involved in reaction time experiments. The apperception pro- cess is now generally regarded as equivalent to the process of attention or of focussing the object. We do not agree with those observers who maintain, that the reaction of which the time is measured is practically a reflex action pure and simple, and not a psychic act. It is impossible to eliminate the ps3"chic element from consideration, and its existence is most assuredl}- a pre-requisite. The facility of reaction will vary directly with the development of the cerebral mechanism ; but, without the psj'chic pre-requisite what becomes of the reaction ? The very nature of the experiment is dependent upon the existence of a will which is freed from all distractions. Ex- pectant attention helps to facilitate the reflex action, but it does not form the only psychic element to be considered in reaction time experiments — i.e., expectancy is a pre-requisite, and con- scious volition is a requisite, in all time-reaction experiments. Expectant attention facilitates the process of conscious guidance ; it does not determine the actual activity itself. The instruments emploj'ed to test reaction time are : — (T) The •■Bowditch Xeuromoebimeter," or "nerve-reply measurer,"' which has been employed by "Warren.f (2) The "Hipp Chrononoscope,"' * Landois and Stirling, " Text Book of Human Pliysiology,'' 3rd edit, p. 685. t " Journ. of Physiology," vol. viii., 1887. 538 APPENDIX B. which is recommended by Jastrow.* (3) The " A-fomn Chrono- scope " introduced by Galton.f (4) Marey's Chronograph has also been used.^ In order to measure the simple reaction time with tactile, auditory, and visual sensations, the discrimination time, and the choice or volition time, Waller § uses a clockwork and cjdinder covered with smoked paper, a chronograph, and Marey's tympana. The reaction times are taken, according to Waller's methods, as follows : — To measure the simj)le reaction time with tactile, auditory, and visual sensations. — Tactile. — The subject, blindfolded, places a finger on a lever. The operator taps the finger. The subject responds by i>ressing the lever as soon as he feels the tap. The interval between the two marks on the smoked cylinder gives the measure of the reaction time to a tactile stimulus. Auditory. — The subject, blindfolded, places his hand ready to press the lever. The operator strikes the lever so as to make a sharp sound. The subject responds by pressing the lever as soon as he hears the sound. Reaction time as before. Visual. — (The butt-end of the lever is painted white, the rest of the apparatus and the movements of the operator are hidden by a screen.) The lever is depressed quickly and quietly. The subject responds as soon as he sees the white end move down. Reaction time as before. Take an average of the observations in each case. To measure the discrimination time. — A double lever is now used. Tactile. — The subject, blindfolded, places the index-finger of each hand on each lever, it being agreed that he is to react only to a touch on one side ; sometimes one, sometimes the other, finger is tapped by tlie operator. Take the average of ten resi)onses made in succession without mistake. Auditory. — A single lever is struck, now with a small bell, now with a bit of wood. The subject, blindfolded, has to answer only to one or other of these two sounds. Take average as before. Visual. — (The butt-ends of the two levers are painted of different colours.) The subject has to signal the movement of one or other of them as agreed upon. Average as before. The result = simple reaction time. -|- discrimination time. To Tueasure the volition time. — Repeat the previous series of observations, but with the understand- * " American Journ. of Psychology," Dec, 1891. t "Journ. of the Anthropol. Institute," Aug., 1889. + Cf. " La Methode graphique," part ii., chap. II. § "Tuke's Dictionary," p. 1021. PSYCHO-PHYSICS. 539' ing that the left-hand is to be used to signal touch, sound, or sight in connection with the left-hand lever, and the right-hand for differing stiruuli of these three kinds in connection with the right-hand lever. Average to be taken as before. The result = simple reaction time. + discrimination time. + choice or volition time. Reaction time in tlie sane. — According to Jastrow,* the influences affecting reaction time may be (a) objective, or affect- ing the condition of the experiment ; and (h) suhjective, or affecting the attitude of the reactor. The objective influences are due to the nature of the impression, the intensity of the stimuhis. and the mode of reaction required. The subjective influences are derived from the subject's foreknowledge of the experiment, the effects of distraction, the direction of the attention, practice and fatigue, individual variations, and varia- tions under abnormal conditions. The influences affecting com- plex reactions are merely extensions of those already named. Beadion time in the insane. — According to Bevan Lewis, in the earlier stages of general paralysis the reaction time to visual stimuli is uniforml}' delayed, and later on both visual and acoustic stimuli show a retardation in the response. In chronic alcoholic inscmity there is delay in reaction time for both acoustic and optic stimuli. In epileptic insanity there is also delay ^vhich tends to exceed the retardation in either general paralysis or in chronic alcoholic insanity. Bevan Lewis says, " It will be apparent, from the observations on heaWnj subjects, that, whereas from twelve-hundredths to eighteen-hundredths of a second formed the limit of variability for acoustic stimuli, and fifteen- hundredths to twenty-two hundredths for visual stimuli, in the insane the former is only exceptionally below twenty- hundredths, and the latter rises from twenty-four-hundredths to thirty-hundredths of a second. j The fundamental outcome of these time-reaction experiments would appear to be, that some people react more readily than others, and that bodil)- or mental perversions may further or retard the reaction. The practical value of such investigations will doubtless be proved in future. * " Tuke's Dictionary," p. 1068. t " Text Book of Mental Diseases,"' 1889, p. 136. 541 INDEX, A. Aboulia, 449, 4o4 Accommodation phosphenes, 267 Acquired idiocy and imbecility, 501 ^Esthetic feelings, 387 After-images, 326, 332 After-vibrations, 272 Agenesis of cortical elements, 500 Ageusia, 265 Agoraphobia, 272, 450 Agrammatism, 365 Akataphasia, 438 Akusis, 273 Albumin in nerve-substance, 58 Alcohol, 477, 521 Alexia, 434 Allbutt, Clifford, on congenital syphilis, 476 Alliteration, 437 Allochiria, 279 Althann, 84 Amnesic states, 341 and aphasia, 362 in hypnosis, 349 partial, 361 periodic, 346 senile, 359 Anaesthesia, 278 Analgia, 279 Anarthria, 365 Anatomy of cortex, 24 Andriezen, 40, 41, 42, 43, 359, 417, 522 Angular gyrus, visual centre in, 95 Anencephalus, 499 Animistic theory, 15 Anosmia, 266 Anxietas tibiarum, 283 Aphasia, ataxic, 364 commissural. 364 sensorial, 364 transient, 439 Aphemia, 437 Ajjperception, 205 Aj)petites, morbid, 453 Apselaphesia, 279 Arnold, 82 Arterioles of cortex, 65 Association fibres, 107 Association school, 17 Atavism, 475 Ataxaphasia, 365 Atomistic hylozoism. theoiy of. 161 Attention, 291 adjustment of, 299 and genius, 300 morbid condition of, 301 neural processes, of, 294 psycho-physical theory of, 293 reflex, 297^ voluntary, 298 Aubert, 189 Auditory centres, 99, 100 paths, 100 Automatic actions, 47, 420 Azam, on memory, 347, 348 542 INDEX. B. Baginsky, 503 Baillanjer, 26, 261, 263, 288 Bain, 17, 154, 293, 294, 388, 392, 425 Baldtinn, 3, 17, 338 Ball, 249, 320, 321, 322 Baratoux, 247 Bastian, 57, 91, 109, 125. 126, 137, 191, 274, 283, 293, 362, 425, 435 Baxt, 45 Beach, Fletcher, on cono-enital syi^hilis, 476 Beaunis, 234, 349, 360 Bechterew, 190, 433 Beevor, 101, 105, 108, 125 Belief, 319 Bell's law, 115 Berkley, 34 Bernhardt, 57 Bernstein, 'y2, 81 Bibra, 59 Billod, 449 Binet, 234 Bland/ord, ■21 o, 276 5/eMZer, 243, 245 Bloch, 217 Blood in insanity, 513 Bodily diseases as causes of in- sanity, 508 Boll, 58 Bolton, 185 Boulimia, 399 Bradyphasia, 365 Braid, 327 Brain, double, 312 movements, 75 vascular supply, 63 Bramwell, 351, 352, 424, 440 Brierre de Boisniont, 263 Broca, 25, 101, 312, 364 Broivne, Crichton, 425 Brown-Sequard, 312 Bruce, 73 " Bucket, theory " of hallucina- tions, 256 Burckhardf, 76, Buret, 209 r8, 87 c. Cajal, Ramon y, 25, 26, 28, 32, 53, 54, 55, 315 Calderwood, 155, 158 Camx>hell, 438 Carpenter, 6, 420, 449 Carter, 43 Catalepsy during hypnosis, 530 Caudate neuroglia fibre-cells, 40 Cells, relation between, 38 Cerebral affection and insanity, 520 arteries, structure of, 67 cortex, 27 fluid, regulation of pressure of, 70 locahsation, 92, 104 value of, 109 Cerebration, unconscious, 165 Cerebrin, 60 Cerebro-spinal fluid, 73 Chabalier, on secondary sensa- tions, 247 Charcot, 63, 64, 92, 125 Chemical properties of nerve-sub- stance, 56 Choice, 410 Cholesterin, 60 Chorea, 518 demonomania, 489 Chossat, 59 Christian, on hallucinations, 269 Cingulum, 108 Climate, influence of, 495 Clouston, 445, 452, 475 Coccitas verbalis, 434 Cohnheim, 65 Collective hallucinations, 268 Colour blindness, 200 sensation, 201 Colours, simple and mixed, 199 Common sensation, 189 INDEX. 543 Comte, loU Conception, 304 physiological, 310 psycho-physical theories of. 308 Conduct, 440 in the sane, 443 insane, 443 Conductivity of nerve-cell, 44 nervous impulse, o2 Congenital idiocy, oOO syphilis, 476 Consanguinity, laws of, 474, 477 Consciousness, 125 in lower centres, 141 the accompaniment of nerve- action, 31o Control of feelings, 444 thought, 444 loss of, 445 self, 444 Cormcinder, 59 Cortex, anatomy of, 24 arteries of, 65 Cortical structures, arrangement of, 25 Coupland, 149, 154, 171, 176, 392, 409 Courtier, 234 Cramer, 282 Cranioschisis, 500 Cretineux, 407 Cretinism, 407 semi, 407 Cyclops, 499 Cyples, 146, 158 Cysterna ambiens, 71 chiasmatis, 71 corj)oris callosi, 71 intercruralis, 71 magna cerebello-medullaris, 71 D. Dancing mania, 489 Daniletvski, 57 Barkscheintsch, 95 Dartvin, 155, 388, 462 Deaf-mutism, 436 Deafness, psychical, 100 Be Crozant, 278 Degeneration and genius, 465 instances of, 466 theory of, 468 objections to, 469 Deiters, 32 Dejerine,, 25, 91, 125 Deliberation, 410 Delusional insanity, 329 Delusions, 329 origin of, 330 Dendrons, 31 Descartes, 153 Desire, nature of, 412 Diabetes, 479 Diakanou', 60 Diemerbrock, 138 Digestion, disorders of, 510 Disgust, feelings of, 401 Dispositions, inherited, 471 Bonders, 75, 203 Double-brain, 312 Doubt, insanity of, 320 Boicn, Langdon, 476 Dreams, 286, 290 Brechsel, 58, 60 Brobisch, 335 Dualism theory, 18 Buchenne, 284 Buret, 63, 64, 65. Ecker, 25 Eckhard, 45 Eclampsic imbecility, 501 Effort, feeling of, 388, 425 Emotions, 375 disorders of, 393 theory of, 375 Empirical psychology, 14 Encephalocele, 500 511. ixi>i:.\. l']ii(l('iiiic crctiiiisiu, ■■)l>i' insanity, 4!U Enfjclmann, .'57 I'jitoiitical ])iils(', i'()7 l^pidiMnic insanity, tsl, t'.tl Epilepsy, impulses in, 4").". Jaeksonian, r)17 masked, ")17 Epileptic idioey, 501 Ksij^urol, i^c:?, 441) Ealcnhn-fi, 284 Eirald, •Mi, ")8 E-nwr, l.'ii), \r>-2. lCx()i)htlialmic goitre, •")1!» Expression, movcniciits in, .".SO physical, oSl) External factors in dcvclopnient. 480 Eye-nnivcinciits, !)(> F. Fnlret, PA-2 Fear, morbid states ol", lO.'J Febrile affections and insanity, 51.") Ff'chner, 153, 293, 294, 89G Fechner's law, 179, 180 Feeling, 373 aesthetic, 404 connected with h(»])r and fear, 403 disorders of, .">!>;', inner sense, 400 intellectual, 404 in the insane, 402 of shame, reproach, etc., 404 ])hysiol()«ical thfiory of, 387 rational, 405 relation to kiiowiri;;, 374 tone of, 383 varieties of, 390 Ferricr, 25, 92, 99, 102, 105, III, 123, 125, ]3f5, 239, 388, 425, 427 Fibrse proprise, 107 Fibre-cells, 40 Fide, 20(J I'Mrst impressions, .">.".."> Eisclwr, 57 Flcchxig, 91, '.i;;, 91i, IOC Floarcm, 1 12, 1 1."), Id;', Fluid, cerebro-spinal, 7") Folic a deux, 491 Fore-brain, 130 Forgetfulness, 340 Fossa Sylvii, 71 EoaiUe, 294 Fouruir, 2()0 Foveje glandulares, 75 For, Loiuj, 82, 83, 81 Franklin, theory of colour-vision, 202 Er'nlilich, 2<)() FrdiiHiii II, .')7, •"(>> Frontal IoIm-. I2(! Fiihninal inn' psyclioscs, I 17 Functional liypcra'niias, S|, 525,, 52(i Functions of nrrvcs, 10 G. (iatton, 243, 271 Gaintjce, 57, 59, 00 (lasqiu-t, 493 (iri(fi'l, 85 (icnci'ic ideas, ."{17 (icnius and attention, 301) and defeneration, 4t)5 nature of, 4(i2 G('()(]hc(jan, 5! ) (lihnon, 88 (ilobus hyHteri(Mis, 51 1 (ioJdHchnHdrr, 18(;, I'ls, I'l'O, 2H5 (loUji, 25, 20, .•'.;!, 31, 53 (ioiln; 203 aoUz,H:',, li:;, 125, 120, |:;i, .-.I fiotch, 53, 120 (lOut and insanit v, 170 GowcTH, 3, 100, I I."., 135, 171, 278 Grand nial. •", |j INDI'lX. 545 IniHhrii, K(l, H7 inilinirl, 'jr,, !>;{ /rl'.vinji r, hi(i, '.'(lO, L'7HS in, 'JM liatlitiid^y <'i', -7-1 pHVcllii-iiiittdl', L'77 Vlll'iclicM III', 'JIIO IhtmiltDii, !).'!, '.M. 107 Ihnnilloii, Sir II'., KiS, :\\)-2 I la|i|iiii(',s,s, I'i'fliii;;' dl', .'lil7 ll<(rrin, l-JO IhirlDKiini, I, -JO!) Il<(nlniii, -'7«'{ //-(((/, W, -JHI ll("ariii«', i)it ('(Mili'c i'oi', !ti) pi'i'vci'.sioii.s ()!', i.'7() Nciisaliiiii <)!', |!)| I ii'.irl, (li,s('ii.si>H t»r, oil* ll( idiiiliiiiii, IlT) III il:iiii(iiii, l\7 Ihlmholh, :'|0 II. mull, :,()\ II. iiri, -j;!! 1 1. iisilit II, i;i| //. //i<(/7, 17, -Jl, ;iiiL' l!»l, -JOI), 2:22, 231, I li'i'i'tliiai'v luniroMi'.s, •I7.'l Ihrinn, 7(i, 'JOI 1 1. mill II 11^ 111, 170 llrii.hiiir, (i;{, (il, do lllm-li, \m llilzi.j, ill, 1 10, [-s,, I;; I ll.iililSDii, 17, ;!!»-' Ilnj/.liii.i, 1 1:{, 1H2 lloppr-Sri/liv, (')() //m-.v/ri/, liH, -).•{, !)|, '.i;;, 1, lO.,, ILT), ll'O. Iloriric:, ;{7 I, .'{HI lloiiiliii, I!)H lliiiiiiDj/] \-jr, IliiilliHiuiii-.liivLsuii, '2X, lOl, li'.'j, ijo, iL's, iij, loj, ;}|J, : •l2o, .OOl', r,!K, .'■,i>(i lliniir, 17 lliiiil.r, 100 llll.llijl, L'O, ML', id") I Ivdrciiccplialdccic, oOO Ily(lr()('('|i|ialiis, AOO llypaku.siH, i^J^ ll.vpiil^iii, L^i) II ypi'r;<'s(lu'Hia, l!7!) I I \ pciakiisis, 272 ll.vpcrMl^^iii, i;70 ll,vp('i-!ill(>iili(Mi, :!0l res nils of, ;{()2 II.Vpt'i'wtMisiii, L'Or) llypcniiiit'sia, .'Ui(i llypcro.siiiiii, 2(i(i ll_Vp(>rp.st>lapii(«sl!i, 27!) I l_vpiM'tr()|)liii' idiof.v, AOI llypiiii>>'o^'i(r illii.sidii.s ami liall iiiitidiiH, 287 llypiidsi.s, TiJO aiiiiK'sja and aphasia no liiH((»i\v dl', ."ii'it im'iiioi\v ill, 'M\) nit'iilal sdilo in, i^M mcllidd.s df, .VJO. .sympldin.s dl', o.'lO \dlil inn ill, li'-l I ly pii;',ciisia, •_'()•") I lypd|i.solapli(>sin, 270 llypo.siuia, 2(!(i 0(1, 121, :i.VI, III, 546 INDEX. I. Idiocy, 449 Illusions, active, 230, 239 definitions of, 228 in dreams, 286 of perception, 229 passive, 229, 230 Images, latent mental, 337 primary and revived, 338 Imagination, 323 a constructive process, 324 images, 326 morbid conditions of, 329 neural process of, 326. Imbecility, 499 Impulses, epileptiform, 452 excessive, 451 general, 452 homicidal, 453 morbid, 450 nerve, 50 sexual, 452 suicidal, 453 Inattention, 302 Incisures of Schmidt, 36 Infancy, disorders of, 499 Inflammatory idiocy, 501 Inherited dispositions, 473 Inhibition, 427 theories of, 428, 429, 431 Insanity of doubt, 320 delusional, 329 Instincts, 375 Intemperance, 477 . Intercellular connections, 53 Internal factors of dcveloiiment, 460 Intoxicants, 521 Invariable concomitance theory, 148 Ireland, 282, 312, 406, 436, 475, 514. Irradiation of functions, 115 Irresolution, 448 James, 9, 11, 19, 21, 91, 126, 140, 160, 163, 175, 210, 214, 220, 231, 236, 239, 250, 254, 258, 284, 307, 318, 356, 375, 423, 426, 462, 533 Jastrow, 539 Joly, 463 Judgment, 317 degree of perfection of, 318 K. Kammlcr, 189 Kant, 392 Kiesow, 184, 185 Krnn'nthesia, 283, 442 Kirchhoff, 110, 114, 141 Klinke, 283 Kdlliker, 53 K'oppe, 271 Krsepelin, 368, 369 Krause, 57, 82 Krohn, 185 Kiiline, 36, 58 Kupffer, 36 Kussmaul, 364 L. Ladd, 10, 12, 18, 49, 111, 147, 187, 199, 207, 213, 221, 224, 384, 442, 533 Laiblin, 198 Landois, 279 JMuge, 376 Langendorjf, 185 Langer, 73 Latent mental images, 337 Laycock, 121 Lead poisoning, 523 Lecithin, 60 Legrain, 438, 478 Lehmann, 243 Leibnitz, 21, 378 INDEX. 547 Lepsius, 243 Lethargic state in hyi^nosis, 530 Leubuscher, 449 Leuhossek, 192 Lewinski, 220, 284 Lewis, Bevan, 2-5, 26, 28, 29, 30, 38, 39, 40, 42, 43, 68, 70, 72, 91, 344, 359, 400, 453, 521, 539 Lemj, 86 Leydig, 37 Lichtenfels, 266 Lichtheim, 434 Liebermeister, 74 Liebreich, 61 Linea terminalis, 71 Lipps, 222 Local memories, 142 Localisation, cerebral, 104 of mental faculties, 111, 211 Logorrhoea, 437 Lotze, 21, 212, 384, 385 Lower centres, consciousness in. 141 Luciani, 91, 139 Ludu'ig, 425 Lussana, 246 Luys, 368 Lycantlai'opy, 482 Lyman, 288, 289 Lymph-cisterns, 71 Lymphatic system, 70, 72 M. Magnan, 342 Majendie, foramen of, 78 Marinotti, 26 Masturbation, 506 Materialistic theory, 17 Material monad theory, 121 Maudsley, 355, 368, 453, 463 Maury, 289, 483 McDowall, 267 Mechanical restraint, 394, 451 Medullated fibres, 34 Meissner, 32 Melius, 103 Memory, 332 active, 333 in general paralysis, 358 in hypnotic states, 349 in organic brain disease, 358 in stui)or, 344 local, 142 methods of cultivating, 334 passive, 333 proper, 332 psycho-physical theory of, 335 secondary, 332 Mendoza, 247 Meniere's disease, 272 Meningocele, 500 Menopause, 507 Menstruation, 507 Mental automatism, 342 faculties. 111 pathology, 6 physiology, 6 Mercier, 15, 147, 315, 386, 392, 429, 441, 446 Merkel, 187 Meschede, 408 Meijer, 59, 75, 240 Meynert, 57, 65, 70, 80, 82, 87, 91, 101, 106, 109, 115, 120, 127, 130, 144, 389, 419 Michelson, 185 Mickle, 270, 278, 438, 512 Microcephalus, 500 Microkinesis, 456 Micropsycho^s, 459 Mill, J. S., 113, 152, 155, 156 Mills, 17, 100, 500 Mimicry of disease, 490 Mind, 149 evolution of, 154 methods of study of, 149 stuff theory, 159, 163 subjectivity of, 143 Misery, 394, 397 Moelii, 91 Moizard, 504 548 INDEX Monakow, 91 Money, 504 Monism, 19 Monoideism, 290 Monomania, 330 Moon, influence of, 49;j Moral defects, 406 insanity, 405 Morel, 453 Morphinomania, 524 Mosso, 76, 88 Motions and sensation, 172 Motor nerves, 102 Mott, 91, 92 Movements, 432 in the insane, 432 of eye, 96 of speech, 436 Midler, 60, 258, 388, 425 Multiple monadism, 21 Munk, 91, 96, 100, 113, 117, 125, 127, 144 Milnsterberg, 156, 217, 222, 293, 419, 427 Muscular sense, 190 perversions of, 282 sensation, perception of, 220 Mutism, 436 Myelocele, 500 Myxoedema, 519 N. Nansen, 37 Nasse, 271 * Nativistic theory of perception, 208 Natural selection, adecjuacy of, 472 Naunyn, 76 Negative after-images, 327 variation, 52 Neiglick, 246 Nerve-cell, 28 conductivity of, 44 physiology of, 43, 144 processes, 31 sizes, 29 Nerve-elements, energy, 175 impulse, 50 nutrition of, 79 substance, chemical properties of, m sp. gr. of, 57 Nerve-fibres, classes of, 49 functions of, 49 non-meduUated, 34 structm'e of, 34 Nerves, motor, 102 sensory, 90 Nervous discharge, 430 resistance, 430 Neuralgia, 279 Neural inference scheme, 12S Neuroglia cell elements, 40 Neuro-keratin, 58, 59 Neurons, 31 Neuroses inherited, 475 Newhold, 323 Netoington, 344 Nishet, 464, 465 Nordau, 140 Nothnagel, 139 Nuclein in nerve-substance, 58 Nutrition of nerve-elements. 79 0. Object, consciousness, 151, 380 Occasionalists theory, 15 OccuiDation, influence of, 495 Olfactory centre, 101 Optic fibres, 96 Original capacities, 461 Ormond, 16 Pacchionian granulations, 73 Pain, laws of, 378 Panic, 450 Parageusia, 265 INDEX. )49 Paragraphia, 365 Parakusis, 273 Paralgia, 279 Paralytic idiocy, oOl Paramnesia, 368, 369 Paraphasia, 36-5 Parous, 60 Parosmia, 266 Passy, 234 Paul hem., 388 Perception, 20-j abnormal conditions of, 226 illusions of, 229 of muscular sensation, 220 of spatial order, 210 of visual space, 221 physiological conditions of, 206 theories of, 208 special channels of, 21;"i Pericellular sac, 72 Perivascular channel of His, 67, 71 system, 68 Perroud, 247 Petit mal, 342 Petroivskij, o8, 60 Pettingen, 19o Philippe, 234 Phonisms, 243 Photisms, 243 Phrenology, 109 Phthisis, 475, ol4 Physical environment, 49o Physiological psychology, 9, 12 Pierce, 217 Pinel, 4.03 Pleasure, laws of, 378 Pollak, 59 Polyi'deism, 296 Polyzoism, 21 Porencej^halus, 500 Post-hypnotic suggestion, 534 Prsefrontal lobes, 134 Pre-esta1)lished harmony, theory of, 15 Presentationism, 156 Presentative feelings, 391 representative feelings, 391 Pressure phosphenes, 267 sj)ots, 189 Preyer, 217 Projection cell, 33 system, 106 Prosencephalon, absence of, 499 Protagon, 61 Protoi^lasmic cell, 42 Psychical deafness, 100 Psychological process of inference, i31 Psychology, 3 empirical, 14 Psychopathic epidemics, 481 Psycho-physical parallelism, 11 Psycho-physics, 535 instruments employed in, 537 lines of investigation, 536 methods, 535 reaction time, 537, 539 Puberty, 506 Puerperiura, 507 Pulsatory movements of brain, 77 Pulse in insanity, 513 Purkinje, 198 Q. Quantitative relation between blood and cerebro-spinal fluid, 74 Quinke, on Pacchionian glands. R. P»,anvier, nodes of, 35 Ratiocinative method, value of, 133 Recepts, 317 Recollection, 333 Reflex action, 45, 419 attention, 297. Pegis, 279, 523 Regression, law of, 353 Peid, 392 )50 INDEX. Religion as a cause of insanity, 493 Religious impostors, 487 pilgrimages, 487 Ilcmak, So Rendu, 92 Rtepresentative feelings, 391 Ilei)roach, feelings of, 404 Re-representative feelings, 391 Resolution, 410 Retinal shadows, 207 Pu'tzius, 25, 40, 192 Revington, 475 Reymond, 92 Rheumatism, 476 Ribot, 293, 301, 335, 342, 343, 345, 353, 369, 449 Ritti, 269 Robertson, 530 Romanes. 239 S. Sachs, 500 Salivation, 510 Sandjord, mZ Savage, 240, 265, 267, 273, 276, 279, 343, 344, 476, 516 Schafer, 30, 37, 43, 50, 53, 91, 93, 96, 99, 106, 125, 134, 187, 192 Schiff, 125, 385 Schlossberger, 59 Schneider, 374 Schopenhauer, 209, 374 Schrader, 112 Schreiber, 76 Schtdtze, 37 Schwann, 35 Scrofula, 475 Seasons, influence of, 495 Seglas, 277 Senile amnesia, 359 Sensation, 170 analysis of, 1 70 and perception, 171 characters of, 177 excentric projection of, 212 Sensation, function of, 183 local characters of, 183 maximum intensity of, 179 motions affecting, 172 of special senses, 184 quality of, 182 secondary, 243 Sense feelings, 391, 393 Sensory paths, 90 perversions, 225 origin of, 225 Sentiments, aesthetic, 393 intellectual, 393 moral, 393 Seppili, 91 Shame, feelings of, 404 Shaw, 269, 277 Sherrington, 98, 99, 103, 107 Shuttleworth, 476, 477 Sight, 93, 196 perversions of, 267 Silbermann, 503 Simon, 497 Skae, 453 Smell, 101, 185 centre for, 101 perversions of, 334 Smith, R. Percy, 530 Social environment, 480 Sollier, 378 Soltmann, 503 Somnambulism, 530 Spatial order, perception of, 210 Specific gravity of nerve-sub- stance, 57 Si^ectral illusions, 483 Speculative manias, 489 Speech, after sunstroke, 439 defects of, 437 during fatigue, 438 in general pai"alysis, 439 in the insane, 437 mechanism of, 433 movements, 436 Spencer, Herbert, 9, 124, 155, 160, 206, 209, 334, 374, 382, 385, 391, 406, 462 m])Ex. 551 Spina bifida, oOO Spinal affections, rAd Spiritual theory, lo Spitzka, 269, oOO, 506 Stammering, 437 Starr, 91 Steinbach, 198 SteinbrUggc, 246 Slehier, ill, 112 Stellate fibre-cells, 41 Stewart, 335 Stump/, 217, 222 Stuttering, 437 Subarachnoidal space, 73 Subject-consciousness, 151, 380 Suggestion, 334, 533 SuUi/, 151, 205, 229, 238, 293, 300, 30*5, 375, 411, 412, 4.:6 Sunstroke, 504, 505 Surditas verbalis, 434 Sympathy, 393, 401,490 Syphilis, 476, 516 congenital, 476 T. Tactile corpuscles, 187 Tactual perception, 277 Tamhurini, 491 Tarantism, 489 Taste, 102, 184 centre, 102 perversions of, 265 Taylor, 453 Teeth in insanity, 510 Telepathic hallucinations, 268 Temperaments, 378, 394 Temperature sense, 189 spots, 189 Thane, 96 Thelohan, 234 Thompson, 475 Thudicum, 61 Tigretier, 489 Time relationships of sensations, 380 Tinnitus aurium, 272 Tone of feeling, 379, 380 Tonnini, 491 Touch, centre for, 92 sensations of, 185 Traumatic idiocy, 502 Trigonum olfactorium, 101 Tripier, 91 Trollard, 75 Tuke, Batty, 23, 88, 268 Tuke, Hack, 6, 248, 269, 277, 290, 405, 490, 495, 532 Tumultus sermon is, 365 Turner, 25 Tyndall, 9 U. Unconscious cerebration, 165 Urbanfschitsch, on secondary sen- sations, 247 Urinary system, diseases of, 509 Uterus, diseases of, 508 Y. ]'an der Kolk, 475 Vascular supply of brain, 63 Vaso-motor centre, 81 Velocity of blood circulation, 85 Venous circulation, 74 Verbigeration, 437 Veyssiere, 92 Vicq d'Azyr, 108 Vierordt, 198 Vignier, 235 Visual apparatus, 95 centre, 95 space, i^erception of, 221 Voigt, 59 Volition, 409 a delayed reflex, 411 during hypnosis, 424 nature of, 412 psycho-physical process of, 417 Volkmann, 221, 222, 236, 373, 395 INDEX. Voluntary action, 421, 442 Von Jaksch, 68, 59 Von Kries, '200, 217 Vulpian, 111 W. Wcdlnce, loo Waller, 115, 118, 119, 126, 131, 145, 156, 425, 538 Ward, 156, 157, 164, 172, 176, 257, 294, 374 Warner, 456 Water in nerve-substance, 57 Weber, 170, 179, 182, 184, 185, 219 Weisbach, 57 Weismann, 472 Wernicke, 106, 364, 433 Westphal, 439 Wiglesworth, 477 Will, 409 as a delayed reflex, 411 definition of, 409 freedom of, 413 Impairment of, 448 Will, nature of, 412 psycho-physical processes of, 417 Willis, circle of, 77 Winslow, 367 Witchcraft, 484 Woakes, 83 Word-blindness, 365 deafness, 100, 365 Worm-Muller, 59 Wundt, 19, 91, 125, 130, 156, 180, 184, 201, 205, 209, 219, 222, 292, 294, 374, 377, 386, 392, 425 Wyllie, 363 Young-HelmhoUz theory of colour vision, 201 Ziehen, 14, 46, 173, 175, 179, 182, 261, 289, 292, 295, 308, 331, 379, 415, 421, 433 rardon ct Snns Printers, M'iiie Office Court, Fleet Street, London, E.G. JIo. 3. Lcn.loit, 7, Great Marlborotigh Street, March, 1S96. A SELECTION J. & A. 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