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ASSISTANT PHTSIOIAN, AND LEOTCBEB ON BOTANY TO THE LONDOIf HOBFITAIi; rOBMEBLT PHTSIOIAN TO THE EAST LONDON HOSPITAL FOB OHILDBEN WITH FIFTY-OME ILLUSTRATIONS NEW YORK D. APPLETON AND COMPANY 1, 8, AND 5 BOND STREET 1886 U,: I; AIM' PREFACE. This work is addressed to those who are interested in studying Man as a living and thinking being. Mind is the highest faculty of man ; what Mind is we do not know, and probably we cannot know, but there is abundant evidence that mind is in some way connected with brain-action. In man, the manifestations of mind are very slight in those whose brains are small and ill formed ; defective action of the mind is often found to be coincident with physical disease of the brain; injury to the brain may deprive a man of his mental power. In animals, the signs of intelligence are in some degree proportional to the size VI PREFACE. and structure of the brain. A strong line of argument on this point has been put forward by Dr. Bastian.* I have found it convenient to use the term " mentation " for that physical action of the brain which is associated with the phenomena of mind ; as thus defined, mentation is a function of the brain, physical in kind, and capable of physical investigation. In the arguments here used it is postulated as a working hypothesis, that all physical phenomena are due to physical causes, or necessarily. follow upon certain physical ante- cedents, and that every physical change is due to a purely physical force. The methods here employed are those used in physical research; forces are studied in the bodies or material objects where they are seen, the physical expression of such forces being noted as an index of the actual but invisible. * " Brain as an Organ of the Mind " (International Soienoa Series), p. 188. PEEFACE. Vll In looking at any example, or mode qf expression, processes of analysis are used till we get at such elements of the phenomena as are capable of physical inquiry, and whose relations may be demonstrated. Biology, medicine, and philosophy, with their working hypotheses, are drawn upon for facts, analogies, and arguments. I have aimed at practical results rather than intellec- tual satisfaction alone, hoping thus to assist those engaged in scientific work and others engaged in social life. The general scheme and purport of this work may be gathered from the first chapter ; the more practical and illustrative descrip- tions are contained in chaps, viii. to xiv. Summaries are appended to certain of the chapters (see index). The chapter on Art Criticism illustrates the principles and arguments used throughout the work : as this may possibly be read by some without the preceding chapters, the principles of analysis of expression are here repeated ; VUl PREFACE. they can be passed over by the reader who became acquainted With them in the earlier chapters. The index has been rendered as complete as possible to enable such cross references to be made as may be required for a complete study of the scheme of the whole work. F. TV. 24, Hauiey Steeet, W. CONTENTS. CHAPTER I. PAGE rNTBODVCTOBT 1 CHAPTER II. EXPRESSION. The term "expression" explained — Speech expressive of life ; speech, a criterion of lite — The uniform coexistence of two phenomena makes the one an expression of the other — Abstract properties, and their objeotiye signs j criteria of mind — Comparison of an idiot, and an intelligent man — Certain sounds and a tracing of the pulse express the action of the heart^Signs due to an afferent force; action of the sight of an object upon children ; a ther. mometer indicates heat; the sensitive flame — The tele- phone exhibits impressionability; a receptive part, an expressive part, and an additional force thrown in — The phonograph exhibits localized impressionability, which is permanent — Impressionability and retentiveness in a child — Expression, direct and empirical — Impression- ability and retentiveness — Nutrition; its signs — Move- ments in plants ; by pulvini, by unequal growth — Expres- sion by form, colour, temperature — Vital processes can only be studied by their expression ; the importance of appreciating this in biological work — Summary 11 X CONTENTS. CHAPTEE III. KXPKESSION IN MAN AND IN ANIMALS. PAGE The fact of expression does not prove vitality — In living things expression is the ontoome of nutrition — Nutrition not considered here, only its expression — Expression when the outcome of processes in the subject is called direct — Growth results from local nutrition ; such processes are termed trophic — Nutrition is an expression of life — Per- manent impressionability ; it is opposed to evolution, it may be expressed by reflex action — Retentiveness need not be permanent — Development and reflex action as modes of expression — Apparatus for reflex movement; reflexes may be congenital, or acquired — Eeflected action, as expression by form or colour — Any outcome of function may be expressive — Expression by colour, sound, change of function in a part — Movements of an actor in anger — Trophic action illustrated by the growth of crystals, growth of the body — Coincident development of parts ; coincident defects in imbeciles — Properties demonstrated by external forces — Heredity— Expression of the emotions — Summary 31 CHAPTEE IT. MODES OP EXPRESSION BY MOVEMENTS, AND THE EESULTS OP MOVEMENT. Movement >• physical and visible action j it is often ob. served in physiological inquiries ; it is correlatable with other modes of force — A movement expresses the action that produces it — Examples of expression by movement : anger, laughter — Eesults of movement — Expression by the voice, apparatus of porcupines, stamping of rabbits — Secondary movements — Work done the result of move- ment — Posture as a result of movement —Subsidence of movement in sleep, in fatigue, and when the attention is attracted — Spontaneous and voluntary movements — Movements of a bee from flower to flower — Summary ... 48 CONTENTS. xi CHAPTER V. MOVEMENTS AND THE RESULTS OP MOVEMENTS CONSIDEEED IN THE AESTEACT, OE APAET JEOM WHAT THEY EXPEESS. TAG IS Movoments are means of expression — Movements classified as reflex, voluntary, spontaneous — The attributes of a movement are its quantity, kind, and time — Time of a movement most conveniently recorded by the graphic method — Frequency and duration, the importance of con- siderations as to time — Two niovementa, considered in relation to time, may be synchronous ; this may depend upon an organic union of the motors, or upon each working in similar rhythm — Expression may consist of coincidences or combinations of movements — -The number of possible combinations of synchronous movements of n subjects is 2m, the number of sequences of such combinations is unlimited — Actions described as a series of movements — Description of a dog in terms of movement and growth — Co-ordinated and inco-ordinated movements — Walking described as a series of movements — Movements of an aggregation of independent individuals — Principles of analysis of movements — Description in anatomical terms — Contrast of movements of small parts and large parts of the body In their physiological significance — Inter- differentiation — Collateral dilferentiation of parts — Sym- metry of movements, indicating like action on both sides of the brain — Asymmetry of movements common in the higher functions — Classification of movements : according to anatomical analysis; according to the physiological principles of analysis given above; as intelligent and non-intelligent; as synchronous or non-synchronous; as occmring in regular series ; as accompanied by feelings, other classifications are suggested — Summary OG CHAPTER VI. PHYSIOLOGY OE EXPEESSION. Modes of movement in plants ; in the amoeba ; the ascidian has a nerve-mechanism, and apparatus for reflex move- ments — Nerve-mechanism of vertebrates — Nerve-mus- cular apparatus; nerve-muscular action — Do certain nerve-centres produce certain movements ? — Perrier's xii CONTENTS. IPAGB experiments — Cerebral localization — Nerve-centres — Visual perception indicated by movements — Time requisite for a reflex movement — Inhibition of movement — Physio- logical effects of light, in man, in plants — Light stimulates ^ trophic and kinetic action — Effects of light in the new- born infant ; movements stimulated, inhibited, co-ordi- nated — Eetentiveness to effects of light — The brain of an idiot not thus impressionable to light — Summary of the efifecta of light — Extrinsic stimuli, mediate and im- mediate — Trophic action of light — Summary of effects of light on plants 82 CHAPTER VII. PATHOLOGICAL FACTS AND EXPRESSION IN PATHOLOGICAL STATES. Disease may destroy or irritate parts of the brain — Destruc- tion of corpus striatum — Lateral deviation of the head and eyes — Effects of iixitation in contrast with destruction of a. brain area — Eliects of disease on diflEerent sets of muscles — Facial palsy — Localization of disease — Epilepsy ■ — Chorea — Analogy to movements in plants — Experi- ments with the mimosa — The study of chorea — Finger- twitching in nervous children — Tooth-grinding — Head- aches in children ; the physical signs — Cases of athetosis — Defects of development ; their frequent coincidence ... 104 CHAPTER VIII. i POSTURES CONSIDERED AS MEANS OF EXPEESSION. Definition of a, posture— Simplicity of study — Historical records of postures — Postures of all parts — A change of posture is movement — A posture is due to resultant action of muscles and their nerve-centres — It is a direct mode of expression — Pree or disengaged parts most expressive A limb labouring is not susceptible to mental expression Organic postures, as from difficult breathing — Postures due to gravity— Effect of gravity on plants— Gravity acts differently duriog sleep— It can affect the postures of the CONTENTS. xm PAGE face — Postures due to reflex action — Spontaneons postures —Fallacies — ^Classification and analysis of postures — Coin- cident postures — Symmetry — Postures in art — Postures in animals — Postures in plants — Summary ... ... 140 CHAPTER IX. P03TUEES OP THE UPPBB EXTREMITY. Method of examination — Anatomy — The convulsire hand contrasted with the hand in fright — The feeble hand and the hand in rest — The straight extended hand, normal — Application of the principles of analysis — Straight ex- tended hand with the thumb drooped — The nervous hand, seen in art — Energetic hand the antithesis of the nervous hand — Table giving analysis of postures, and application of the principles — Principles of analysis —Anatomical analysis — Small parts contrasted with large parts — Inter- differentiation — Collateral differentiation — Symmetry Excitation of weak centres — General excitement or weakness — Analogy — Antithesis — Fallacies — Methods of determining whether a posture is the outcome of the spontaneous action of the nerve-centres ... ... 154 CHAPTER X. EXPEESSION IN THE HEAD. Positions and movements of the head defined— Flexion the only symmetrical movement — Action of light in cansing head movements ; varying effect of such stimulus in different brain conditions — A weak posture — Effect of gravity — The head usually free — Application of the principles of analysis to head postures — Movements of the jaw — Physiognomy, or certain forms of the head — Summary ... ... ... ...~ ... ... ... 182 CHAPTER XI. BXPKESSION IN THE HUMAN FACE. The face as an index of the mind — Definition of the face ; its structure — Facial muscles and their nerve supply ; the sympathetic nerve — Form, colour, and mobile con- XIV CONTENTS. FAGE ditions of the face — Direct expression of brain action in the face ; expression by coincident development — Action of the facial muscles — Method of analyzing a face : the npper, middle, and lower zones ; symmetry ; analysis of the expression of anxiety — Expression by trophic signs, skin — The intellectual and the rnlgar face — The necessity of considering nerve-muscular signs as well as permanent conditions — Faces of idiots — Nutrition of the face ; a dull and a bright face — What may be seen in a man's face — Impressions of previous movements of the face — Mental suffering compared with bodily suffering — Asymmetrical expressions ; winking, snarling — The long face, due to paralysis of the nerve on one or both sides : due to mental states ; facial palsy from brain disease — Intellec- tuality of facial movements — The face in fatigue; the expression of headache — The disengaged face free for mental expression — Cases of expression from brain disease — Conflict of muscles in the face ... 193 CHAPTER XII. EXPEESSION IN THE EYES. The eyeballs : their position and the mechanism for their movement — Iris, a muscular apparatus ; its nerve supply — The pupil contracted by light, and accommodation for near vision ; its reflex dilatation, and its variation in con- ditions of emotion and on brain stimulation — Mechanism of the eyelids— Importance of distinguishing expression by the eye and the parts around — Movements of the eyes — Loss of associated movements of eyes under chloro- form, and in deep sleep — Movements of eyes from brain stimulation— Horizontal movements most common At- traction-and repulsion of the eyes by sight of an object — Spontaneous movements — Byes free or disengaged — Mental states expressed by attraction or repulsion of the oyes^Horizontal and vertical movements contrasted Intellectuality of upward movements ... , 214 CONTENTS. XV CHAPTER XIII. EXPRESSION OP GENEKAL CONDITIONS OF THE BRAIN AND OP THE EMOTIONS. PAGE Expression of consciousness — Sleep — Fatigne — Exhaustion — — Irritability — Nutrition — Best — Activity — Impressiona- bility — Expression of instinct and mentation — Expression of pain — The ataotion of the beautiful 225 CHAPTER XIV. EXPRESSION OP MIND IN THE INFANT AND ADULT. Materialistic questions only entertained — The criteria of mind, what are they ? — Physical study of signs of mind from infancy upwards — A subjective condition is only known to us by its physical expression — Brain properties necessary to mentation — Impressionability — Retentive- ness — Relation of ontcomings to afferent stimulus — Com- parison of an infant with the adult, and an idiot with a healthy child — Description of an infant : its develop- ment and signs of potentiality — Impressionability : its attributes ; delayed expression of impressions — Modes of expression are criteria of mind — Expression of distress — Memory — Subjective conditions studied by their expres- sion—Thought 210 CHAPTER XV. ANALYSIS OF EXPRESSION. Analysis of the expression of fatigue — Localize the ex- pression — Observe trophic signs, postures, movements — Analyze and classify movements according to the prin- ciples given — Analysis of Darwin's description of laugh- ter, and Sir Charles Bell's description of joy — The importance of such analysis — Pope's description of Achilles — Study of a nervous subject — "A school in- spection" — National modes of expression .. . ... ... 255 XVI CONTENTS. CHAPTER Xyi. CONSTDEKATIONS AS TO THE ATTKTEVTES OP A PEOPEKTY OB rUXCTION — TIME, (JUANTITT, KIND ; AND A3 TO THEIE EEL ATI ON. PAGE The attributes of a, property or function : time, quantity, kind — Attributes of the functions trophic and kinetic action, in one subject, in two or more subjects — Combinations and sequences of action — Proportional growth; equal proportional growth; similar development — Analogy between series of kinetic and trophic actions — Special combinations of action may result from afferent forces ; this an important element in evolution — Heredity — Summary ,,, ... 267 CHAPTER XVII. AET CEITICISM. Art teaches the physiologist ; all men can study expression — Bulwer's opinion — All expression of feeling is by nerve- muscular action — Importance of such studies — Expression of mental states — Hand and face specially indicative of the mind — Venns de' Medici, the nervous hand — Diana, the energetic hand — Composition — Etruscan drawing — Cain at Pitti Gallery, the hand in fright — The Dying Gladiator — ^Writings of Camper; his descriptions of ex- pression—Antony Baphael Mengs— Study of nerve- musoular action — Weakness should not be expressed in place of beauty — The free hand — The object of figure composition in art — Fixed and mobile expression — Prin. ciplea of analysis ... ,,, .. ... ... ... 2S9 CHAPTER XVIII. LITEEATUEB. Bulwer — Hartley — Gregory — Camper — Blane —Marshall Hall — Tyndall — C.Darwin — Bibliography, with dates ... 321 CONTENTS. XVll CHAPTER XIX. METHODS AND APPAKATU3 FOB OBTAININO QBAPHTC RECORDS OP MOVEMENTS IN THE LIMBS, ETC., AND ENUMERATING SUCH MOVEMENTS AND THBIE COMBINATIONS ; PROBLEMS TO BE INVESTIGATED BY THESE METHODS. Movement as a result of vital action is capable of physical experimentation — Early attempts to record movements — Apparatus described : the motor gauntlet ; the recording tambours ; the contact-making tambour ; electrical coun- ter; method of using the apparatus — Problems; as to muscular twitching in exhaustion— Movements of an infant — Inhibition by light — Measurement of differentia- tion of movements — Retenti veness — Signs of emotion — Potentiality for mind— Co-ordination — Athetosis — Chorea 347 [vu££ M 363 LIST OF ILLUSTRATIONS. no. 1. Longitudinal section of a pulvinus ... 2. Chorea flexor movements ... .,, 3. Nervous system of an Asoidian 4. Upper surface of the hemispheres of the monkey 5. The left hemisphere of the monkey ... ... 6. Upper surface of the human brain 7. Lateral view of the human brain ... 8. Hydrophobia. Head repelled by sight of water ... 9. Tracing showing how the spontaneous movements of an infant were inhibited by sound and, again, by a strong light ... 10. Eight hemiplegia, with cerebral facial palsy, right side 11. Left hemiplegia, with cerebral palsy, left side 12 and 13. Tracing of involuntary movements of the finger in a nervous child 14. Finger- tracings in chorea IB. Tracings of movements in athetosis 16. Cases of athetosis showing hand postures 17. Dying Gladiator .. . 18. The convulsive hand... 19. The hand in fright 20. The feeble hand 21. The hand in rest 22. The straight hand ... 23. The straight extended hand with thumb drooped 24. Hand intermediate between the hand in rest and the straight hand ... 25 and 33. The nervous hand ... 1G3, PAGB 25 68 84 86 87 88 89 98 101 108 109 112 113 128 130 145 156 157 158 159 160 161 161 297 XX LIST OF ILLUSTRATIONS. no. PAGE 26. The energetic hand ... 164 27. Complete paralysis of the right side of the face 202 28 and 29. Face o£ imbecile ... ... 205 30. Paralysis agitans, in advanced stage 213 31. Tracings of the spontaneous movements of an infant's hand during fifteen minutes ... 245 32. Venus de' Medici 296 34. Diana ... ... 298 35. Feast of the gods 300 36. Cain ... ... 302 37. Hercules at rest 305 38. A countenance perfectly placid ... 307 39. Expressing surprise ... 307 40. Contempt ... 308 41. Complacency, friendliness, tacit joy 308 42. Laughter ... 309 43. Sorrow ,,, 309 44. Weeping ... 310 45. Diagram showing facial zones... 320 46. Motor gauntlet ... ... 349 47. Motor gauntlet on hand 350 48. Junctions for motor tubes ... 351 49. Frame supporting the recording tambours, and eleo. trical signals ... ... 352 50. Contact-making tambours arranged in circui t ... 353 51. Electrical counter ... ... ,. ... 354 PHYSICAL EXPRESSION, 9 ITS MODES AND PRINCIPLES. CHAPTER I. INTRODUCTORY. This work has been written as the outcome of observations made on children and adults, and it is hoped that, inasmuch as it is the result ot observa- tions on humanity, it may be found of some social use. The principles here put forward and illustrated have been applied very frequently to the considera- tion of questions of importance to individual men, women, and children, and this gives me some confidence that others may find practical results from these studies of the modes of expression. Children are the subjects most often referred to: and this is the result of many years' study of childhood. When I commenced the special study of children, it soon struck me that a sound and well-developed nerve-system was of primary importance as, firstly, giving vitality, and the power to endure organic diseases ; and, secondly, on account of the great 2 2 PHYSICAL EXPEESSION. impressionability of the nerve-mechanism in child- hood, and the immense importance of such impres- sions on the future moral and intellectual condition of the child. In every scientific inquiry, whatever be the ultimate object in view, it is necessary to use the utmost accuracy as to method of procedure. The present work contains an analysis of some of the usual means of investigating the nerve-system, with a view to the establishment of an experimental method of inquiry as to the forces leading to its growth and development (see chap. xix.). This is a somewhat bold and ambitious project, and no one can be more conscious than the author of the difiiculties that lie in the way. One special object in view is to show how much accuracy and clear- ness of insight may be obtained in biological work by dealing as much as possible with objective signs and physical forces only, always adhering to the postulate that every objective phenomenon must be the outcome of physical action. My early studies were on the size, shape, and propcft-tions of the head, as indicative of the brain within. Such observations led to but poor results ; still, they were useful. The results of these obser- vations are embodied in the account given of co- incident development (see chap, xvi.).* I next set about considering how our knowledge of brain functions had been obtained, and analyzed the methods employed in such physiological work ; and * Mr. Charles Roberts's excellent manual on anthropometry gives much valualile information on this subject. INTRODUCTOKT. 3 soon I saw that the principal methods of making physiological, and clinical, observations of brain conditions were derived from noting its motor- functions. Then, noting in all cases the motor out- come of brain action, I studied the spontaneous postures, and analyzed them. In making such observations the spontaneous movements of«the subjects attracted attention ; they were difficult to analyze, but still it was obvious that, as physical phenomena, they were capable of analysis, record, and classification. An experi- mental method was then devised by which move- ments could be recorded with the aid of the graphic method described in chap. xix. The tracings thus obtained* were submitted to the criticism of mathematical and statistical friends, to whose help I am greatly indebted. Their remarks made it obvious that time, frequency, combinations, and sequences in series, were the attributes that should be noted in studying movements. Such knowledge as to method could not have been ob- tained without experiment. Following on these considerations, I founded the most important of the principles for the analysis of movements. The other principles which it is sought to establish are the result of analyzing recognized clinical modes of procedure. I should like to have formulated analogous principles with regard to nutrition,! but that seemed too wide a subject for the present volume ; still, T take this opportunity of saying that * See Fig. 31, p. 245. + See chap, xvi.," Analogy between Tro^liic and KineticActions. 4 PHYSICAL EXPRESSION. I think the detailed and experimental method of studying movements in the body, and their causes, may throw much light upon the laws and pro- cesses of nutrition and evolution. It was a part of my original plan to deal in this volume with some of the laws of nutrition; but, as the work advanced, it seemed better to defer dealing with this subject, as also with regard to some evidence as to the forces at work in producing brain evolu- tion in the individual : * so here we deal with the principles and modes of expression of hidden conditions as a matter preliminary to other studies. Inasmuch as these studies were primarily under- taken as an attempt to discover the physical signs of the brain conditions which lead to the potentiality for moral, and intellectual character, it is not sur- prising that they led to the study of the physical signs of the brain conditions giving capacity for "mind."t Still, I was unwilling here to enter upon the physical study of mind, and have dealt only with certain matters preliminary thereto. In dealing with the phenomena of mind, the present work is a preliminary stepping-stone ; if we observe and analj'ze all physical phenomena coinci- dent with the manifestation of mind, we may obtain data for studying the action of the physical causes aiding the development of mind. This method of procedure appears to me more likely to lead to practical results than any subjective process to introspection of the feelings. * See chap. xvi. f See chap, xiv INTEODUCTORY. 5 In accordance with these views, I have en- deavoured throughout this work to avoid speaking of consciousness, or feeling, as the cause of any- mental phenomenon.* It has not, however, been convenient always to do so, but I hope that this rule has been adhered to in all important statements. Movements and the results of movements, being purely physical actions, are the criteria looked for as indices or expressions of the various brain states. No attempt is made to form an idea of what life, nutrition, mentation, or any other vital property or process may be ; the signs of vital phenomena are dealt with, not the living origin of those signs. The term " mentation " is used to imply the function discharged by the brain when the phenomena of mind are displayed. Frequent reference is made in the succeeding chapters to observations on infants and young children. It appears to me a strictly scientific method to observe and classify the signs which indicate the potentiality for mentation, the early and advancing signs of mentation, and concurrent phenomena. The earliest of these signs are move- ments and the results of movements, and these are purely physical phenomena, capable of being sub- mitted to expei'imental inquiry. Reference is frequently made, by way of illustra- tion, to examples in vegetable life.f If we really accept some form of the evolutionary theory as a working hypothesis, it is reasonable to make • See " Expression of Consciousness," chap. xiii. f See chaps, ii. and vii. 6 PHYSICAL EXPRESSION. analogies from the processes proven in plants to processes seen in higher organisms. If physical forces have played a large part in bringing about evolution, we should surely study the processes in simple organisms. If light and gravity are proven to cause certain phenomena in plants, and if we see similar phenomena in men, why should we assume those phenomena in man not to be due to light and gravity, but to be due to "mind," or " feeling," or " consciousness," which we cannot by any scientific process directly deal with ? It has often struck me that recent biological inquirers, in the just desire to study only what is capable of physical investigation, have ex- amined material structures rather to the neglect of the equally materialistic forces displayed in the matter, and that motion which has been so care- fully and satisfactorily studied by the physical experimentalist * has not been sufficiently studied by the physiologist. I think that movement in living beings is capable and worthy of detailed study. Following on these lines of thought, this work has been written, showing how largely the expression of vital functions may be described in terms of movement — and movement is capable of physical investigation. In observing living organisms there are two principal methods that may be employed. (1) Observation of the body.f or corporeal, material structure of the subject : this, may be a histological • The woike of Grove and Tyndiill. t See specially chap. xvi. as to proportional development. INTRODUCTORY. 7 inquiry. (2) Observation of the ingoings and out- comings. It is the latter set of signs that are principally studied in this volume. As to the observation of the ingoings and out- comings of the subject observed, the following propositions may be laid down : — (a) The ingoing quantities of material equal the outcoming quantities of material, plus or minus any change in the quantity of material of the body of the subject. (6) The ingoing quantities of force equal the outcoming quantities of force, plus or minus any change in the quantity of force stored in the subject. (c) Some force must be ingoing if any change occurs within. (d) The difference, or change in kind, between the income and the outcome is due to changes occurring in the organism. (e) Conversely, changes occurring in the organism may in part be expressed by describing the differ- ence, or variability in kind, between the income and outcome. (/) It follows that we may reasonably observe and describe the difference between the ingoing and outcoming forces, and also observe changes occurring in the material structure of the subject. The animus and object of the inquiry described in chap. xix. is to determine, by means of observa- tion and an experimental method, the effects of external circumstances in aiding and producing the physical or material basis of mind 8 PHYSICAL KXPRESSION. The primary assumption is made that mentation is dependent upon the material structure of the body, and that the structure, properties, and functions of that body are the result of external forces. When any principles are laid down for practical guidance in this inquiry,* the endeavour has been made to show that they are widespread "uni- formities in the operations of nature," or laws applicable to questions outside the proper scope of this work, and that they are laws or uniformities in the operation of nature of wide action in various biological problems. The endeavour has also been made to show that these laws, as defined and explained, give the foundations for a true experi- mental inquiry, and that they are in harmony with many of the laws defined in biology, in psycho- logy, and physiology, also in some cases with the laws of sociology and human social life. It seems to me a matter of great importance to study the attributes of every property observed, the time, quantity, and kind of property; in some cases the " kind " can be described in terms of time and quantity. This is entered upon and illustrated in chap. xvi. The principles and methods of analysis used (see chap. XV.) are the outcome of daily observations, and have been applied over and over again to many cases in dealing with my living patients. This is mentioned in the hope that others may be induced to see whether these principles are in accord with * See specially chaps, ii.-iv. INTRODUCTORY. 9 logical and scientific procedure, and as a justifica- tion of this attempt to introduce new inquiries into the nerve-system. I have omitted any attempt at cerebral localization, and do not think that the present work has greatly suffered thereby. The work done by others in that direction has been of immense service to me, and possibly this work may indirectly forward that most desirable inquiry. Many purely medical facts might have been intro- duced, but it appeared best not to produce them in this volume. The present work has been sent out under its present title as an instalment of a larger work in hand. I think that the accurate observation of the motor outcome of brain action, and the observation of the effects of external forces upon such func- tions, will give us much information as to the eflect of physical forces in causing the evolution of the individual, and the development of mind by educational processes. Glancing over the succeeding chapters, they may be classified as follows : — The first five chapters explain the scope and general method of the work. The scope and meaning of the term " expression " is explained to include all outward manifestations of hidden things. Thus it is seen that vital phenomena can only be studied by their expressions, or physical signs ; on the contrary, all vital and inscrutable phenomena may be studied by these expressions, if we know how to observe and record the physical signs of the expression. 10 PHYSICAL EXPRESSION. A certain number of facts in physiology and pathology are referred to in chaps, vi. and vii. It is only by the study of such facts that the significance and explanation of the modes of expression in man can be elucidated, and I hope that the principles defined may be applicable to the description of certain pathological states, especially such as chorea and epilepsy. Pathological anatomy alone does not explain these ; probably they will be best described in terms of movements and analyzed by these signs. Direct analogy may be made between the area of nerve-muscular signs in hemiplegia from a destructive lesion of brain, and one-sided chorea, and brain fatigue or excitement affecting the two hemispheres of the brain unequally (see chap. vii.). The chapter (xv.) on the analysis of expression gives examples of the application of these studies to matters of daily life. It is in particular hoped that this account will be of use to those who study children, and need to read in their outward expres- sion the actual state of their nerve-system. Artists and those who give literary descriptions of the mental and emotional conditions of man have taught us much, and to them the study of the modes of expression is a necessity (see chap. xvii.). Certain extracts have been given (see chap, xviii.) from some of the older writers, which show that, though modern knowledge may make it more easy to speak with precision of the principles involved in expression, still the matter has long been studied and the thoughts here formulated have been lon^ extant. A bibliography is attached to chapter xviii. CHAPTER II. EXPRESSION. The term " expression " explained — Speech expresdve of life ; speech a criterion of life — The uniform coexistence of two phenomena makes the one an expression of the other — Abstract properties, and their objective signs ; criteria of mind— Com- parison of an idiot, and an intelligent man — Certain sounds and a tracing of the pulse express the action of the heart — Signs due to an aiferent force ; action of the sight of an object upon children ; a tlieimometer indicates heat ; the sensitive flame — The telephone exhibits impressionability ; a receptive part, an expressive part, and an additional force thrown in — The phonograph exhibits localized impressionability, which is permanent — Impressionability and retentiveness in a child — Expression, direct and empirical — Impressionability and retentiveness — Nutrition ; its signs — Movements in plants ; pulvini, by unequal growth — Expression by form, colour, temperature — Vital processes can only be studied by their expression ; the importance of appreciating this in biological work — Summary. "Expression," in its widest signification, is the outward indication of some inherent property or function. An expression is a physical sign which is accepted as a criterion of the property, because the two are found by experience to be more or less uniformly coexisting phenomena; and if the manifestation of the special expression (or physical 12 PHYSICAL EXPRESSION. sign) is found with absolute uniformity, whenever the property or function in question is present, we may look upon that physical sign as an absolute proof of the presence of the property. Thus, in a man the power of speech proves the existence of " life ; " physiological knowledge shows that we cannot have speech proceeding from a man unless his body has life. To prove the property life in a human subject it is quite sufficient to prove that he can speak. We do not know what life is in the abstract, but to prove that a man can speak is to prove that he possesses what we call " life." It follows, then, that the physical sign " speech " is a criterion of life, or we may say that speech is one expression of life. We see, then, that the uniform coexistence of two phenomena in a subject, of which one is a physical sign, enables us to look upon that physical sign as an expression of the other phenomenon. This uniform coexistence may be demonstrated by empirical experience sufficiently extended, and attested by various observers, under va.rying cir- cumstances. If we analyze the expression of the property " life," given above, we shall learn some- thing further as to why we may speak of " speech " as an expression of life in the subject. , It is known that speech is always the result of certain move- ments of the respiratory apparatus, the tongue, and the mouth. Respiration, even when unattended by speech, and when found in animals incapable of speech, is uniformly expressive of the property " life." Further, physiology has shown that active EXPEESSION OF MIND. 13 properties and functions of the brain are necessary for speech. It follows then, that speech is an expres- sion of two phenomena in the subject — ^respiration and brain action. Speech is an expression of respiration and brain action, because it results therefrom, or is an outcome of respiration plus brain action ; so this illustrates the truth that* if a certain physical sign is always the result, or outcome, of some one property or function, that physical sign is an expression of that property or function. It is often convenient to study at the same time a certain property in the abstract, and its outward or physical signs. When we study " mind " as a property of man, we must define its physical signs, or the criteria by which we appreciate the function " mind." If we compare a healthy and intelligent man with an idiot not possessed of the properties called " mind," or possessing them only in a very low degree, we shall soon see a marked difierence in the physical signs. The intelligent man speaks well, his atten- tion is attracted by objects of beauty or usefulness. The idiot does not speak intelligibly, his attention IS not attracted by objects of beauty, his movements are not subservient to his own wants. A man of mind affords expression by the manner in which his attention is attracted, by his good speech, and by his movements; these objective facts are, then, the expression of his mind. Any property that can be possessed by a subject may be indicated by some physical sign, which is then called the expression of that property in that particular 14 PHYSICAL EXPKESSIONi subject. Temperature is an expression of heat in the subject ; growth in the seed is an expression of life in its organism. We have briefly touched upon some forms of expression of the brain, which is an organ of the body, the special forms of expression considered being the outcome of its properties and functions. We will now discuss the expression of one or two other organs. We form a judgment of the con- dition and functions of the heart by the state of the pulse, the sounds heard over the heart on auscultation with the stethoscope, and by feeling the impulse of the heart, etc.; to form a more accurate judgment we may take a tracing on paper of the movements of the pulse by an instrument termed a sphygmograph, and we obtain a line on paper, indicating the movements of the heart, by means of another instrument called the cardiograph. The sounds and the characters of the impulse of the heart, and the tracings of the movements of the heart and pulse, are expressions of the action of the hidden organ — they are the outcome of its action, and the criteria by which we judge of its functions. W^e have hitherto spoken of modes of expression where certain signs indicate properties, either because they are found uniformly to coexist with those properties, or else because they are the direct outcome of such properties. We now come to consider how expression may be a result of some force afferent to the subject, falling upon it, but not solely and directly the outcome of its intrinsic EEFLEGTED ACTION. 15 properties and functions. This may be conveniently termed " expression by reflective action." It is a matter of common observation that we do not know a man's mental and moral qualities till we have seen him tried by the circumstances of life. In forming a judgment of a man's character we seek to observe his actions under various cii'- cumstances. The man's actions under these various circumstances are partly the outcome of his organi- zation and character, and are partly due to the special circumstances acting upon him. Such expressions are in part the effect of circumstances acting on the man. Such a case illustrates this subject, but is too complex for a convenient analysis. Let us take a simple example. Suppose two children, both healthy, intelligent, and of the same age. Hold a pleasing toy before one child, and let it be hidden from the other. We now see the expres- sion of pleasure in one child's face, accompanied by gestures of delight ; not so in the other child ; but if both are then allowed to see the toy, each will present expressions of joy. The sight of the toy is the cause of the expression of joy in the children. Here, then, the expression is not solely the mani- festation of the spontaneous outcome of the organism of the child ; the sight of the toy falling upon the children is necessary to stimulate the expression of joy or amusement. Again, if an experiment be tried by placing the toy in front of the child while he is asleep, or if awake when very ill, no expression is produced ; or 16 PHYSICAL EXPRESSION. lastly, if the child be very cross and sulky, the sight of the toy may cause no expression of joy. If, on the contrary, the child be "in a very laughing humour," the expression by similar stimulation will be excessive in degree. These considerations show that the condition of the subject is in part indicated in expression when the subject is acted on by external forces afferent to it. In speaking of reflective action as a mode of expression, it will be seen that the line of argument founded upon such an obser- vation may be inverted. If the subject is known to be constant and unchangeable in its proper- ties under the same conditions, any variation in the outcome of its properties or functions is due to a change in the afferent forces or the environ- ment. In looking at a man of known stable con- stitution, in whom no disease or special defect of any organ is discoverable, if we observe some sudden change in the aspect of his face indicating, according to our experience, grave mental anxiety, we may conclude that something has happened to him causing anxiety — some news of disaster or cause of fear, etc. The aspect of his face is the expression, firstly, of his condition ; secondly, it affords evidence that some event has happened affecting him with fear. A thermometer is an instrument not changing itself ; any variation in the volume of mercury in the bulb and stem is due to heat : here any increase in the bulk of the mercury is due to heat coming to the instrument, and the rise of mercury THE SENSITIVE FLAME. 17 in the stem expresses the temperature of the surrounding medium. The sensitive flame is another example of a subject so impressionable that it indicates or ex- presses very faint sounds or aerial vibrations. The following quotation is from a lecture by Mr. W. F. Barrett, delivered before the Royal Dublin Society, January 8, 1868 : — " The lecturer had re- served for the conclusion a flame wonderfully sensi- tive to the slightest noise. The burner which gave this flame was formed of steatite, and consisted of a single circular orifice, through which the gas was forced from a large holder in the lecture-room, with greater pressure than would be attained from the main. The flame was now fully two feet in length ; ' and observe,' said the lecturer, ' how delicate and fragile a thing it appears to be ; for on the slightest noise it drops down a foot. The jingling of this bunch of keys, the crumpling of this paper, the dropping of a small coin, are more than sufficient utterly to break up its height and symmetry. This flame makes no response to the vowels o, u, nor to the labials, but it energetically responds to the sibilants. Repeating the stanza — " Boll on, O rill, for ever I Eest not, lest thy wavelets, Sheen as shining silver, Shrink and sink to darkness;" the flame is unmoved by the first line, but empha- tically bobs at the sounds " rest " and " lest, " and admirably suits its action to the words of the last line, for, when shrinking, the light of the flame 18 PHYSICAI, EXPEESSION. almost disappears. So sensitive is this flame that even a chirp made at the far end of the room brings it down more than a foot. Like a living being, the flame trembles and cowers down at a hiss ; it crouches and shivers as if in agony at the crisping of this metal foil, though the sound is so faint as scarcely to be heard ; it dances in tune to the waltz played by this musical box; and, finally, it beats time to the ticking of my watch. How wonderful are all these facts ! And the more we know of them the more wonderful do they appear ; for this aston- ishing change in the aspect of the flame is produced by an infinitesimal portion of those almost inaudible sound-waves, already enfeebled by their distance from the flame.' " In the telephone we see an instrument of great impressionability, but it exhibits more than this. Two instruments being placed in electrical com- munication, and the instrument having a battery in the circuit, the vibrations of the voice com- municated to one instrument aie conducted to the other ; that is to say, the one instrument is im- pressionable, the second expresses the vibrations received by the first, while the force received from the battery is an active agent or factor in producing the expression. In this arrangement we see an impressionable part,- a conductor of impressions, an additional force thrown in, and a part solely utilized in producing expression. The vibrations of the receiving disc are ended as soon as they arrive, and no permanent impression is left ; there is no retentiveness of the impressions THE PHONOGRAPH. 19 in any part of the apparatus, no permanent impres- sionability. / In the phonograph we find impressionability more or less permanent; but, while receiving im- pressions, the instrument cannot give origin to expressions. The one vibrating plate receives the impressions, and subsequently expresses them, re- tentiveness being concentrated in the tinfoil. As in the telephone, so in the phonograph, an addi- tional force is thrown in. While the impressions are being received by the sounding-plate and impressed upon the foil, it is, of course, necessary that the foil be moved under the needle that indents it, in order that fresh parts of the foil may receive the indentations. The impressionability in the arrangement may be said to be permanent, the indented foil remains indented for an indefinite length of time. We best know the property reten- tiveness in the apparatus by the expression of the sounding-plate when the cylinder is again moved so as to reproduce the original sounds which came to the sounding-plate. The retentiveness is indi- cated by the efferent expression obtained as sound on causing the foil to revolve ; the expression corresponds more or less exactly to the afferent sound producing the impression, although a long period of time may have elapsed- between receiving the impression and giving out the expression. Another thing to be remarked upon as essential to getting expression out of the phonograph is that the indented foil must be made to move the Bounding -plate, and mechanical force must be 20 PHYSICAL EXPRESSION. applied to the cylinder carrying the foil, so as to cause this to move under the needle of the sounding plate, making it vibrate. Impressionability and retentiveness may be ob- served in animals acting in modes almost analogous to those seen in the telephone and the phonograph. Take as an example a child whose attention is attracted by a musical box in action, so that it turns towards it and listens. The sound of the musical box causes vibrations in the child's apparatus of hearing. Suppose that the child is playing with a toy when the music commences ; attracted by the sound, the child's head turns away from its toy towards the musical box, and he claps his hands. This is one effect, one expression of the impres- sion received. Further, the child will, after a certain number of repetitions of the same tune, be so far impressed as to be able to hum the tune, in part at least, under the stimulus of pleasure or a request from the mother; this indicates the per- manency of the impression. The action of vital force in the child is, of course, necessary to repro- duce the tune ; this corresponds to the mechanical energy supplied from without to the cylinder of the phonograph. Another class of expression that must now be considered is what may be termed "empirical ex- pression." Here the expression, or objective sign observed, is not the direct outcome of the intrinsic property or function which it indicates, but we infer from the presence of the objective sign that the special property is present. "This inference is EMPIKICAL EXPRESSION. 21 founded on the observation of the uniform occur- rence of the objective sign and the intrinsic pro- perty, although the two are not related as cause and effect, as in cases of " direct expression." Of course, it may be argued that in this empirical expression the intrinsic property, and the observed objective sign, are both results of a common antecedent cause ; thus both may be inherited alike. It is a matter of great importance to our subject that the difference, and relative value, of empirical and direct expression should be thoroughly understood and appreciated, because it is only the modes of direct expression that can be looked upon as direct evidence of the possession of certain properties. When we look at a living human face totally devoid of movement, or special expression as the result of movement, or even if we look at a plaster cast of the face, it may indicate to us something of the character of the subject. In looking at the impassive face, and the plaster cast, the expression seen is not the direct outcome of brain action, or the condition of the mind. We are speaking here of the more permanent and fixed conditions of the expression, not of fleeting, transient, mobile conditions. Still, there is the fact that the two things — the average action of the brain in marking the average of the man's mind, and the form and contour of the face — coincide empirically; this subject will be more fully con- sidered further on ; * it is the foundation of the scientific study of "Physiognomy." Examples of * See chap. tti. 22 PHYSICAL EXPRESSION. empirical, or indirect; expression, may be seen in organic, and in non-living subjects. When such cases occur in man, or in living animals, or vege- tables, they may be termed " examples of coincident development.'' This empirical expression differs from the modes of direct expression, inasmuch as in the latter, the expression is the direct outcome of the property expressed. The sprouting beard in a boy's chin, is a sign of commencing manhood, not because the one produces the other, but because a widely extended experience of many boys has shown the two things to be usually coincident. Piak-flowered geraniums are plants of feeble con- stitution, not because the colour of the flower directly affects the constitution of the plant, but because pink-flowered geraniums usually have highly coloured leaves, with but few cells con- taining chlorophyll, and the presence of chlorophyll is essential to the nutrition of the plant. Pink flowers are, then, only an empirical sign of feeble constitution in the geranium, but still a sign of value; the real or direct expression of the con- stitutional feebleness is the small amount of chlorophyll in the leaves — the scarcity of chlorophyll is the direct expression of the feeble constitution, because it is the cause of it. Impressionability and retentiveness are properties found alike in living, and non-living subjects; nutri- tion and growth belong to living beings only, or so it is generally considered. By the term "nutrition" is denoted an active vital process, converting pabu- lum into tissue of the organism, or into some new EXPRESSION OF NUTRITION. 23 chemical material, thus evolving force which may be observed in action, either at the point where it is produced or at a distance from it. Nutrition being a, vital, and inscrutable process, we probably cannot know it in the abstract, but we can observe the effects of the process of nu- trition in an organism. The best evidence of the occurrence of* nutrition is found in its results. In many cases nutrition is greatly aided by (if not entirely dependent upon) the action of certain external forces afferent to the subject, so that the results in some degree indicate the action of such external forces. We will consider a few examples. In vegetable growth we may find a simple multi- plication of cells, all similar in their histological or structural characters, as is seen in the tissue termed " primary meristem." Here the expression of nutri- tion, and vital action, is multiplication of cells. In a mass of unicellular plants the result, or ex- pression of, nutrition is multiplication of plants, as in the growth of the snow-plant. In other cases, as in the apex of the stem of a plant, when a bud is being formed, differentiation of the cell-growth results from nutrition, producing embryonic leaves. A more complicated case of nutrition expressed by histological changes, is seen in the cellular body called an ovule, which is found in the carpel of a flower. When the protoplasmic contents of a pollen grain have entered that cellular body, changes follow which Bause an embryo to develop by cell- differentiation in the ovule ; the structural changes observed in the development of the embryo are the 24 PHYSICAL EXPRESSION. expression of the vital effects of fertilization, or sexual impregnation. Other cases of vital action in plants are differently expressive. The action of chlorophyll in the cells of a leaf is known by certain chemical results — carbonic acid gas being absorbed, the oxygen being discharged from the plant, and the carbon retained in its tissues. Here the chemical changes are the expression of the action of chloro- phyll. The growth and vital action of the yeast- ' plant, when living in a solution of sugar, is in part expressed by multiplication of the unicellular yeast- plant — a histological mode of expression — and it is in part shown by the chemical changes of fermentation indicated by chemical results. Numerous kinds of movements occur in plants; two examples will serve our present purpose, showing that movements may be the expression of vital changes. In plants, movement is effected by two principal methods — by unequal growth of the cells composing the growing member ; or by organs termed "pulvini," temporarily or permanently devoted to the produc- tion of movement as their principal function. In the Oxalis (wood-sorrel tribe), and in the sensitive plant {Mvmosa), movements of leaves are seen. In each case the movements are effected by an arrangement of cells at the junction of the leaf with its main stalk; this group of cells is called a "pulvinus." The pulvinus is the mechanism by which movement of the leaf is effected ; it consists of a mass of small cells destitute of chlorophyll, and therefore incapable of performing any nutritive function in the plant, or of taking any direct part in the elaboration of MOVEMENT IN PLANTS. .25 its nourishment. This pulvinus is the lower portion of the petiole, or leaf-stalk ; and the movements of the leaf depend upon its cells, which expand alter- nately, first on one side, then on the other. Struc- turally, the pulvinus consists of small cells arrested in their development while stiU young. These, Tig. 1.— .After Darwin. Longitudinal section of a Pulvinnw, magnified flpvpnty- five times, p p, petiole or leaf-Btallc ; /, fibro-vascular bundle ; 6 b, com mencement of blade of cotyledon. when turgescent with sap, swell up, thus increasing suddenly the bulk of the structure composed of them : and the turgescence leads to motion only — it is not followed by growth ; no nutrition of the plant results from the turgescence. It must be noted that the cells possessing this special function of pro- ducing motion only, fulfilling no direct nutritive purpose, are smaller than their neighbours, arrested 26 PHYSICAL EXPRESSION. in growth, and destitute of chlorophyll. This is the condition of the cells of the pulvinus as long as it is capable of producing movement. In the Oxalis corniculata the pulvinus is developed imperfectly, and to an extremely variable degree, so that it is apparently tending towards abortion. Its cells con- tain chlorophyll ; that proves they have nutritive functions to perform, as well as the production of movement. These cells are more like the normal cells of the petiole than those usually characteristic of a pulvinus.* As to the production of movement in plants by unequal growth of the cells. In the process of germination of the pea seed, the radicle of the embryo protrudes from its case, and direct ex- periment demonstrates that the apex of the root in its downward progress does not proceed in a straight line ; the apex bends first to one side, then to another, moving in irregular ellipses, or rather in a spiral direction, as it descends. This zigzag movement of the apex of the root is due to an unequal growth of the cells composing the growing portion of the root; they enlarge first on one side, thus causing the apex to bend towards the opposite direction, and then the set of cells growing alters. This mode of growth is termed by botanists "circumnutation." The essential principle of this mode of growth is, that the vegetable cells concerned do not grow together, but those on one side grow, then those at another * " Analogy between the Movements of Plants and the Muscular Movements of Cliildren, called Chorea," P. W., rrituh Medical Journal, February 2.1, 1S82. FOKM, COLOUR, TEMPERATUKE. 27 part, in regular series. In this circumnutation move- ment results from the fact that the cells grow in series, not all simultaneously. Form, colour, temperature, are properties as fre- quently observed in non-living as in living subjects. ■ These may, perhaps, be looked upon, and spoken of most conveniently, as obvious properties because the form, colour, and temperature are their own expressions. This statement is not exactly true, but this form of language does not convey any untruth that will vitiate -our use of this term for present purposes. Strictly speaking, " the colour of an object " is a condition of its surface, and what we see and describe, is the reflection of light from it, and the kind of light so reflected is an expression of the molecular structure of its surface ; "the tempe- rature of a body " is an expression of the condition of the vibrations of its molecules ; " the form of an object " is the result of the forces that produced it. The largest possible scope has been given in this chapter to the term " expression," and this has been done with a definite object. Expression is the objective sign of a property of the subject. In biological inquiries we are obliged to study vital processes by their expression in objective signs. Life itself is studied by the results, or objective expressions of nutrition, and growth. It is, then, obviously desirable that we should study all the objective signs, or modes of expression of these vital processes. The subject of expression is dwelt upon in the wide signification here given to the term, because it appears doubtful if, in biological 28 PHYSICAL EXPRESSION. research, dependence enough has always been placed upon the truth of the fact that expressions are objective signs of the properties of the subject. If we are certain that the objective signs seen in expression are either uniformly accompanied by certain phenomena, or that the cause of the special hidden phenomenon is the reason of the visible objective sign, — in either case we may study the hidden condition by studying the outward objective expression thereof Thus, " mind " in the abstract cannot be submitted to direct physical investigation by experiment, but, if certain physical signs can be shown to be the criteria or expression of mind, we may be able to observe these objective signs, and devise experiments for the elucidation of information with regard to their cause. Again, nutrition of a living organism is a subject of which we understand but little, and what we do know is the result of studying the objective effects of nutrition, and its coinci- dences — in other words, the objective expression of nutrition. Swfti'mary. — In this chapter I have endeavoured to explain what is meant in this work by the term " expression," and it is shown that the scope of our subject is wide, dealing with any case where objec- tive physical signs indicate some more hidden phe- nomenon or condition. When a physical sign is a criterion of a condition of the subject, we may investigate that condition by studying the physical sign. The physical sign or expression may be the SUMMART. 29 direct outcome of the condition it indicates, as speech is the direct outcome of respiration and brain action; or the expression and the inherent condition may be found by empirical experience to be uniformly coincident. The expression, or outcome from the subject observed, may be the result of some force afferent to the subject, as the movement of a sensitive flame, which is caused by vibrations of the air, — there the physical sign ob- served, the movement of the flame, is an expression of the vibrations of the air. The physical signs observed may express impressionability, temporary or permanent ; in the telephone the receiving plate is very impressionable, but the eflfect of the vibrations it receives is temporary ; in the phonograph the vibrations received are impressed upon tinfoil, and more or less permanently retained. Impression- ability, temporary or permanent, is frequently expressed in plants, animals, and in man. Those cases may be termed " direct expression " where the physical signs observed are the direct outcome of the property expressed ; an " empirical expression " signifies that the physical sign observed is uniformly found by experience to be associated with a certain property, though the line of causation may not be understood. Nutrition is a property belonging only to living beings ; the term denotes an active vital process converting pabulum into tissue, or evolving force which may be observed in action. The results of nutrition may be in part due to external forces afierent to the subject, and so may in part express them. 30 PHYSICAL EXPEESSION. Form, colour, temperature, are properties that may be expressive in living and in inanimate objects. The movements that occur in the growth of plants are expressive of their modes of growth. CHAPTER III. EXPRESSION IN MAN AND IN ANIMALS. The act of oxfression does not prove vitality — In living things expression is the outcome of nutrition — Nutrition not con- sidered here, only its expression — Expression when the outcome of processes in the subject is called direct — Growth results from local nutrition; such processes are termed trophic — Nutrition is an expression of life — Permanent impression- ability ; it is opposed to evolution, it may he expressed by reflex aotiun — Eetenliveness need not be permanent. — De- velopment and reflex action as modes of expression — Appiiratus for reflex movement ; reflexes may be congenital, or acquired — Eeflected action, as expression by form or colour — Any outcome of function may be expressive — Expression by colour, sound, change of function in a part — Movements of an actor in anger — Trophic action illustrated by the growth of crystals, growth of the body — Coincident development of parts ; coincident defects in imbeciles— Properties demonstrated by external forces — Heredity — Expression of the emotions — Summary. In the last chapter the principles and modes of expression were described and discussed, and it seemed well to illustrate all points by examples taken from living and non-living subjects. The ■ mere fact of expression in a subject is no evidence of vital characters, no proof that it is a living rather than a non-living thing. In the present 32 PHYSICAL EXPRESSION. chapter Tve shall speak of expression in man and in animals, and the illustrations of modes of expression will, as far as possible, be taken from the cases of living beings. The great and striking general difference between the modes of expression in animate and inanimate subjects, is due to the fact that, in the former, vital properties and nutrition are essential. We will commence with the study of the signs of nutrition. The differences between the modes of expression in animate and inanimate beings is, then, due to the fact that, in the former, vital properties and nutrition are essential factors. Ex- pression in the living subject is usually the direct objective outcome of conditions of nutrition ; we therefore consider together the subject of nutrition and the expression of nutrition. As to nutrition per se we have very little to say here, but we are deeply concerned with the modes in which nutri- tion is expressed. It has been said that the most certain modes of expression are those which are the direct outcome of action in the parts involved ; therefore the best modes of expression are the ob- jective results of nutrition. Now, the results of nutrition being many, it will serve our purpose to deal with a few cases only — growth, movement, evolution, retentiveness. Growth is an objective sign of nutrition — a corporeal, structural, or histological change in the subject; the material structure of the subject, not merely its properties or functions, being changed as the result or out- come of this form of nutrition. Local nutrition is TKOPHIC ACTION. 33 necessary to growth, therefore growth is a sign of nutrition. Rapidly growing tissue is believed to be highly nourished, because it is found to be very vascular; and often we may infer the degree of nutrition from the degree of vascularity. That kind of nutrition or vital action which pro- duces growth, or change in the material structure of the subject i^ conveniently termed " trophic action ; " we may speak of expression by "trophic action," and, compare it with expression by movement. When trophic action is the mode of expression, we find some histological change in the subject of growth; when a movement is the mode of ex- pression, there is often no change in the structure of the subject that can be observed as a histological fact, and if we neglect to observe and record that movement, we possibly neglect the only objective sign of the change occurring in the subject. Nutri- tion and growth, when they occur together, indicate or express life in the subject; it follows, then, that any ol the expressions of nutrition and growth are expressions of life. Permanent vm/pressionahility is a very important property, and it was shown in the second chapter that retentiveness may alike be found in animate and in inanimate subjects. Retentiveness in living things may be indicated or expressed in various ways. When in a subject a certain stimulus is always followed by the same expression, we may conclude that the subject is unchanged, or reten- tive at least of the property thus expressed. Retentiveness is, then, not a sign of evolution or 34 PHYSICAL EXPRESSION. change, but of an organism capable of resisting changes. Retentiveness indicated by reflex action may be seen in the infant at birth. The fact of placing an object between its lips excites the move- ments of sucking ; this is a reflex action, and per- sists as long as the individual is an infant. When the infant becomes a man, this reflex is more or less weakened or lost; the mechanism connected -with sucking is not retained in the same condition through life. We see, then, that in this particular mechanism retentiveness is only temporary. Movement, as an outcome of action in an animal, is the result of some force, internal (as nutrition) or external, acting upon the animal. The study of the correlation o£ forces justifies this assumption that visible movement, as the outcome of an organism, expresses either force afferent to the subject, or the result of changes occurring in it — changes which are conveniently termed vital action or nutrition. As examples showing movements expressive of nutri- tion in the organism, the following may be cited. Mechanical exercise in man, such as carrying a weight, has been shown by physiologists to be due to changes in the body, and the movements of the man are an expression of the internal changes. A child in perfect physical health is frisky, plays, runs about, and chatters incessantly till he is tired ; the movements indicate the perfect physical health of the subject, because they are the outcome of the perfect nutrition of the organism. If the nutrition of the body at large is low, as the result of deficient or improper food, or disease of some organ, the DEVELOPMENT. 35 lowered condition of nutrition is indicated by the lessened amount of movement. The dormouse when hybernating has its nutrition lessened, owing to the little food it takes ; its feeble circulation, its lowered temperature, and the absence of move- ments in the limbs are the expressions of its lessened nerve-muscular energy. Development is a very interesting and important study. It is expressed in various modes. In the newly born infant we observe certain conditions indicated by its weight, form, proportions, etc., i.e. certain conditions of its body; we also observe certain functions, movements, reflex actions, etc. These are the expressions of its condition. In the adult the weight, form, proportions, and the move- ments and reflexes, are diflierent from those of the infant, and this difference is an expression of the evolution of the individual After comparing many infants with many adults, and observing the de- velopment of infants into adults, we find that a more or less regular series of similar changes occurs in the body, and in its functions, as development advances from infancy to adult age. This more or less regular series of changes in the body, and in its functions, is the expression of the development, and, in any case, before we can give a full historical account of the development, we must observe all modes of its expression. The life-history of an individual animal is in part the history of its de- velopment ; it includes the description of the body of the individual at every period of its existence, together with all the influences afferent to it, and 36 PHYSICAL EXPRESSION. all the expressions, or efferent functions, coming from it. Reflex action is a niode of expression of com- mon occurrence in man and animals; this will be more particularly dwelt upon as a mode of expression in the next chapter. Drawing a hand away from a hot cup is a reflex action; but the movement is a mode of expression, such movement being usually considered expressive of pain. For the occurrence of a reflex action a certain nerve- motor apparatus is necessary. The simplest appa- ratus for this purpose consists of (a) sensory surface ; (&) afferent nerve-fibres; (c) nerve-cell or centre; (d) efferent or motor nerve-fibres ; (e) muscle. Now, this apparatus for a reflex action may exist at birth, as with the apparatus for sucking; or it may be acquired, as the reflex movement of the face giving expression of pleasure at the sight of a fine work of art, — such reflex, not existing at birth, is said to be acquired. We may, then, have expression by reflex action congenital, or acquired. It seems also probable that reflex actions form an important and very large share of the phenomena grouped as the function "mentation," or the facility of the brain which produces mind. Reflected action is a mode of expression in living and non-living beings. The term " reflected action " signifies a purely passive condition of the subject, all action being on the part of some force afferent to the subject. The expression of a statue is purely passive — the marble does nothing itself; the rays of light falling upon it are in part reflected, enabling REFLECTED ACTION. 37 US to see the statue. The expression of the passive features in man is reflected action; so all expres- sion by colour and pigmentation, form and propor- tions. Reflected action is not per se an indication of vitality or nutrition. "When in an animal move- ment occurs as the result of some mechanical irrita- tion, as tickling, the afferent mechanical agency produces a cWnge upon the sensory surface which causes a stimulus to pass to the nerve-centre, from which an efiierent motor-current then proceeds to the muscles, producing movement. Such movement is called reflex action, or reflex movement, in distinc- tion from the case of the statue, where there is no change or movement in the subject, which is pas- sive, all expression being an offcome, not an " out- come;" the objective cause of expression is the reflected afterent force. Expression may be efiected by colour, or any other mode of objective outcome or ofiFcome pass- ing from the subject of expression to the observer. Conditions of colour are often expressive. The colour of minerals often expresses their properties ; the colour of parts of plants is often very constant and uniform, enabling this character to be used in some degree, as a sign by which an individual may be recognized and classed. The special hereditary characters and breed of many animals are often ex- pressed by conditions of coloration, striping, spots, etc. Light complexion of face, light hair, etc., are expressive of race and climate, equally with dark pigmentation and olive complexion. In point of degree of value as signs, there is no doubt that 38 PHYSICAL EXPRESSION. structural points are of more importance than points of colour. The colour is the result of the molecular condition of the surface ; the general structure is a more widely spread physical con- dition. Sound is one of the commonest modes of expression among animals. The sounds produced are usually indirect expressions. It is very interesting to study changes in the functions of an organism or in part of a living being, and such studies are very important in any investigation of the processes of development. We have, then, to look to the signs or expressions of change of function in an organism, and the most satisfactory kind of evidence is that afforded by ■' direct expression," or some change in the outcome of the action of the subject which can be directly observed as an objective sign. A change of function in parts of the body of a plant or animal is not an uncommon occurrence, and may serve as a means of expression. In the life-history and development of many species a change of function is uniformly met with. A few examples may be mentioned, taking together the change of function and its expression in objective signs. The case of change in function in the cells of the pulvinus of Oxalis has been already given in chap. ii. p. 2C. The body is not fully developed in childhood, and the hair-bulbs in the skin of the face take on active growth about the time of the development of full manhood. In a woman the growth of hair-bulbs in EXPRESSION BY CHANGE IN FUNCTION. 39 the face is usually delayed till old age. The func- tions of the stomach, and its power of digestion, vary at different periods of life, and under different circumstances : the stimulus of food causes an acid secretion to be poured out ; when empty, the secre- tion of the organ is alkaline. In the foetus the lungs are not used as respiratory organs, and at birth the salivary glaq^s are not active. Ants, when first born, possess wings which they soon learn to use, but after a short time they lose their wings and become solely terrestrial animals for the rest of their days. A bar of iron may be magnetized, and its properties are thus changed. In vegetable growth it is very common to find examples of epinasty and hyponasty* alternating, the cells growing first on one side, then on the other. In man certain changes in the larynx in the course of growth cause an alteration in the voice. The action of glands varies from time to time ; e.g. secretion of mucous membranes, etc. If a man is kept long in the dark his retina becomes over- sensitive to light. Definite and permanent changes in the structure and functions of a part are more clearly seen in a species than in an individual ; this is owing to the greater length of life of a species as compared with an individual. Movements are often exceedingly expressive. When observing a man, for the purpose of forming a judgment as to his mental condition, and deter- mining what emotion is most active within him, we take note of his gestures or movements. An actor * Saolis, " Te.\t-book of Botany," 1875. p. 7G7. 40 PHYSICAL EXPRESSION. upon the stage, desiring to represent the emotion anger, imitates, according to his art, the gestures of a man angry in earnest — ^his features are distorted, he makes movements as if he would combat his adversary, etc. These are the actor's imitative expressions of anger. A child, when angry, stamps, gesticulates with his arms, and cries, — these are real objective expressions of his anger ; so also is sorrow expressed by the downward drawing of the angles of the mouth. In chaps, viii. and ix. many examples are given of expression of the emotions by movements as objective signs. The voice, its tone, and its rapidity, are highly expressive of emotions ; the voice is the result of nerve-muscular action. A stooping attitude and spiritless gait indicate that a man is tired or dejected, as compared with his postures when refreshed and energetic. The head is drooped as an accompaniment of shame; it is held erect and firm when defiance is expressed. Physical conditions termed " trophic changes " are often very characteristic and expressive of develop- ment, and of nutrition, in the subject. As pre- viously explained (see p. 3.3), by the term " trophic " action, or change, it is intended to indicate some change in the material structure of the subject, the histological or structural change being itself the expression of what has taken place. Taking one example outside the proper subject of this chapter, the case may be cited of the so-called growth and repair of crystals.* " If a portion of a crystal be See Sir J. Paget's paper, " ^n Address on Elemental Pathology," British Medical Journal, October 16, 1880. REPAIR OF CRYSTALS. 41 broken off or filed or dissolved away, and if then the mutilated crystal be replaced in a solution of the same salt or of an isomorphous one, the lost part will be replaced, the crystal will be enlarged, new crystallized matter will be formed on every surface; but the quantity formed on the injured part will be greater than that formed at any other part, and repair will be more active than mere growth till the proper form of the crystal is regained. Then, when the repair is complete, growth alone will go on, and each part of the crystal, if it remain in the same solution, will increase in due proportion with the rest." Here the reformation of the injured part of the crystal is the objective expression of the action of the forces at work in producing the perfect and enlarged crystal. In a man we judge of the general condition of his nutrition, by the weight of his body in propor- tion to his height, and his general proportions or build in relation to his age. With slight altera- tions of the amount of general nutrition and health, we see slight alterations in the form and outline of the face and figure. The growth of the teeth is indicative of the age of the animal; grey hair indicates senility or depressed vitality ; the size of a fruit indicates the effect of the forces that produced it (see Darwin's " Variation under Domestication ") ; a slight degree of absorption of fat in the body, as the result of slight changes in the conditions of nutrition, causes a dull appearance of the counten- ance ; the smell of some animals indicates the con- dition of their general health. 42 PHYSICAL EXPRESSION. Another important mode of expression in man and animals is that which may be conveniently termed "the coincident development of parts." Observation often shows that two parts of the body usually agree, in having the same proportion of good or ill development. If the one part is well developed, the other part is likewise well developed, and vice versa, although the one part is not the origin of the other, or directly connected with its forma- tion. It may probably be shown hereafter that the good or incomplete development of each of the parts thus found to correspond, is the result of some common antecedent or cause, or that both are alike inherited. Thus we see the colour of the hair, and the colour of the iris, often bear a fixed relation to one another ; the height of the body and its proper- ties as indicated by measurement, usually show a marked degree of correspondence in the same race of men, and in animals of the same species if living under similar circumstances. The subject is dwelt upon in the " Origin of Species," p. 115. Certain properties of a man or of an animal, are only expressed when external forces demonstrate their existence. The capacity to feel joy is proven by the expression of joy when something happens to the subject producing such emotion. The capacity of colour-sense is demonstrated only by aid of coloured objects. In these cases circum- stances external to the individual help to express the properties in question. The property or function heredity is one that must be expressed outside the individual subject. A few EXPRESSION BY HEEEDITT. 43 words only can be said here on the very wide and deep subject of expression by heredity, that is, ex- pression of the conditions of the life-history of the individual, as demonstrated in its offspring, the off- spring showing the effect, or outcome, of forces aflferent to one or both parents. For our present purpose I think we may classify the phenomena of heredity in terms of certain properties : (1) trophic phenomena ; (2) motor, or kinetic, phenomena; (3) reflex action; (4) reten- tiveness. We are here dealing solely with the criteria or objective signs of heredity, not with its essential nature. A general review and considera- tion of the facts of heredity enables us to say that we may look upon the four criteria, above mentioned, as the main modes of expression of heredity as a property in the subject. This mode of expression will be discussed in chap, xvi In concluding this chapter we must refer to " expression " in the more limited sense in which the term is commonly used as regards man and animals. " Expression " is a term commonly used to signify the modes in which we judge from out- ward appearances of the mental or physical condi- tion of the individual at the time of observation ; thus we speak of the expression of pain, joy, intelli- gence, hunger, sleepiness, etc. It is our business here to study these expressions, these outcomes or ejecta, these uniform objective concomitants of the hidden conditions intelligence, hunger, sleepiness, consciousness, feebleness. It is not for us here to study subjective conditions or feelings and states 44 PHYSICAL EXPBESSION. of consciousness, but we are to study their ex- pression or objective concomitants. All that can be observed are the ejecta, or outward visible signs ; the coexistence of the subjective condition is an inference dependent upon the uniform experience that such and such outward or objective sign is always, or almost uniformly, accompanied by a certain subjective condition or feeling. In the ex- pression of physical pain the angles of the mouth are depressed. This statement is justified by the frequent, almost uniform, observation that, when the angles of the mouth are markedly depressed, inquiry shows that there is some source of physical pain in the man or animal ; and conversely, that, in many cases where there is known to be pain, examination has shown that the angles of the mouth are drawn down. It has been said by some that pain must be the cause of the depression of the angles of the mouth. We do not know what pain is; it is a subjective condition. We do know that the depression of the angles of the mouth is due to muscular contraction, and that the muscular contraction is due to a nerve-current from the nerve- centre. It is, then, the condition of the nerve-centre corresponding to the muscles which depress the angles of the mouth, that is so uniformly affected when there is a source of pain in the subject; in fact, all the special irritations which cause pain, seem to affect the nerve-centres of the depressor muscles of the angles of the mouth. This is the knowable objective fact. It seems to me that the ground is cleared for us SUMMARY. 45 in this inquiry by omitting all consideration of the subjective conditions, and considering only the ob- jective facts. In animals the subjective condition is but a very crude inference from the objective facts. Swmmary. — The term "expression,'' as used in this work, does not imply that the subject of which it is connoted has the property life. Nutrition is said to occur only in living beings. We do not know much about the vital process nutrition, but we can observe and study its results, or objective signs. The outcome of nutrition affords the best examples of direct expression. The principal results or ex- pressions of nutrition are — growth, or trophic action; movement, or kinetic' action; evolution, and retentiveness. Growth concerns the material structure of the subject — the kind of action which produces a change in the structure of the subject; it is, therefore, called a "trophic action," in contradistinction to that result of nutrition which only produces movement, and is called in this work " kinetic action." Permanent impressionability, or retentiveness in a living structure, may be expressed by a reflex action ; it is not a process of evolution, but gives a tendency to resist change. Movement is an outcome of changes occurring in a living subject; this is a deduction from the law of conservation of energy. Development is expressed in various modes — by the ratio of growth, weight, and proportions (trophic action), or by series of movements and reflex actions 46 PHYSICAL EXPRESSION. (kinetic action). The mechanism for a reflex movement requires (a) sensory surface; (b) an afferent nerve-fibre; (c) a nerve-centre; (ci) an efferent or motor nerve ; (e) a muscle ; — such ap- paratus may be congenital or acquired. Probably reflex action has a large share in that faculty of the brain which produces mind, and which is here called " mentation." " Reflected action " is a term used to indicate a passive condition of the subject, expression resulting from the mode in which it reflects an afferent force, such as light; such is the mode of expression in a statue. Expressions by form and colour are similar modes. Sound produced by a living being is a result of movement, and as such is highly expressive. Change of function is an important mode of expression; it may be studied in vegetable cells, glands, etc. Movements (kinesis) and the results of movement are among the most important modes of expression, and these are conveniently termed "kinetic," in contrast to " trophic modes " which affect the material structure of the subject. Coincident development, proportional and similar development in the members or parts of a living subject, are interesting modes of expression ; they are trophic in kind. These are discussed in chap. xvi. The facts of heredity are very important and complex modes of expression ; some facts concerning EXPRESSION IN MAN AND IN ANIMALS. 47 a man or an animal are only known by observing the parents and the offspring. As to the subjective conditions in man, no account can be given of their essential character; we can only study the physical signs which accompany the states of brain which produce them. 48 PHYSICAL EXPEESSION. CHAPTER IV. MODES OF EXPRESSION BY MOVEMENTS, AND THE EESDLTS OF MOVEMENT. Movement a physical and vUible action ; it is often observed in physiological inquiries ; it is conelatable with other modes ot force — A movement expresses the action that produces it — Examples of expression by movement: anger, laughter — Results of movement— Expression by the voice, apparatus of porcupines, stamping of rabbits— Secondary movements — Work done the result of moverapnt — Posture as a result of movement — Subsidence of movement in sleep, in fatigue, and ■when the attention is attracted— Spontaneous and voluntary movements — Movements of a bee from flower to flower — Summary. Common experience shows that the manner and kind of movements seen in a man are expressive. Movements may be expressive of the fact that a child sees, and hears. We know that a child hears a whistle, because he moves at the sound; or if he sees a light, this may be indicated by the fact that he turns his head towards it. The movements are expressive of the subject hearing and seeing. Movement as a physical sign, or mode of ex- pression, appears to me a result of the properties IMPORTANCE OF THE STUDY OF MOVEMENTS. 49 and functions of the subject that is particularly worthy of extended and accurate study. Move- ment itself is a physical mode of expression, capable of very accurate observation both in time and in quantity ; it is capable of being easily noted by more than one observer at the same time, and can be recorded by various adaptations of the graphic method. Such records can be preserved, and submitted to analysis by mathematical pro- cedures. Observations of this kind have been largely employed by physiological experimenters, and much accurate knowledge has been thus obtained, elucidating processes of circulation, re- spiration, reflex action, etc. Movement, however produced, whether by vital action, nutrition, or otherwise, can always be shown to be correlatable with other modes of force. It is surely reasonable to observe, record, and study, movements result- ing from vital acfion as an expression of that vital process, and not to confine observation to histo- logical or structural (trophic) effects of vital action. It will be granted by the reader, that movement always indicates some force antecedent to that movement ; it follows that movement in a body is expressive of a force acting upon, or in, that body coincident with the observation of the movement, or antecedent to it. Movements may, then, be studied as modes of expression. In the common experiences of life, movements are accepted as expressive of conditions in the subject, as is easily shown by the analysis of examples. Let us look and inquire, then, whether 4 50 PHYSICAL EXPKESSION. movements can be shown to be a mode of expression in accordance with the meaning of that term given in chap. ii. It is said that a manner of movement is expres- sive. If a movement is expressive, or if, in other words, there is expression in movement, we ought to be able to show what is the condition hidden in the organism corresponding to the visible move- ment. If it can be shown what produces the movement, it is shown what is directly expressed by that movement. It is shown in chap, vi., which deals mainly with questions of physiology, that movements may result from stimulation of the central nerve-mechanism, and it is shown in- ferentially, that movements correspond to the action of the central nerve-mechanism. It is the fact that the movements we observe are, we believe, produced by the action of the central nerve-me- chanism that makes us look upon movements in the body as expressive of the inward condition. Movements are the direct expression of the action of the nerve-mechanism. The terms "manner of movement " and " kind of movement " are analyzed and explained in chap. v. That expression may be produced by movements, and that it is most commonly so produced, can be demonstrated by examples. Anger is commonly spoken of as an emotion or passion of the mind. Bain* says, "The physical manifestations of anger, over and above the embodi- ment of the antecedent pain, are (1) general excite- • "Mental and Moral Science," 1872, p. 261. EXPRESSION OF ANGES. 51 ment ; (2) an outburst of activity ; (3) deranged organic functions ; (4) a characteristic expression and attitude of body ; and (5) in the completed act of revenge, a burst of exultation." Sir Charles Bell * gives the following description : " In rage the features are unsteady. The eyeballs are seen largely ; they roll and are inflamed. The front is alternately knit and raised in furrows by the motion of the eyebrows ; the nostrils are inflated to the utmost; the lips are swelled, and, being drawn by the muscles, open the corners of the mouth. The whole visage is sometimes pale, some- times turgid, dark, and almost livid; the words are delivered strongly through the fixed teeth ; the hair is fixed on end like one distracted, and every joint should seem to curse and ban." Henry Siddonsf illustrates the expression of anger thus : " Thus, as I have been saying, choler adds energy to all the 'exterior parts of the body, but chiefly arms those most proper to seize, attack, or destroy. Swelled by the blood and humours which are thither carried in abundance, they agitate them- selves with a convulsive violence. The inflamed eyes roll in their orbits, and dart forth fiery glances; the hands and teeth manifest a kind of interior tumult, by the grinding of one and the agitation of the others. It is the same kind of easremess which the mad bull and furious bear display, to make use of the arms with which nature ■ • "Anatomy of Expression,'' p. 177. t " Practical lUuotrations of Elittorical Gesture and Action," p. 118. 52 PHYSICAL EXPRESSION. lias furnished them. Moreover, the veins are swelled, especially those about the neck and temples. Ail the visage is inflamed, on account of the superabundance of blood carried up to it ; but this redness resembles not that occasioned by desire or love ; the movements are more hurried and more violent ; the step is heavy, irregular, impetuous." These descriptions of anger, as given by the philosopher, the physiologist, and the actor, agree in ascribing much of the expression of the emotion to movement and the results of movement. Take Siddons' description. He speaks of choler as expressed by energy in the movements of the arms, grinding of the teeth, and agitation of the hands. He tells us of the effect of other movements, or arrest of movement, which he does not describe. He speaks of the limbs as swelled with blood, and the eyes as being congested ; these phenomena are secondary results of spasm in the respiratory muscles. Sir Charles Bell describes movements in the face, and likewise refers to the eflfects of arrested respiration. Anger in animals is in part expressed by show- ing the teeth. Here we have the description of certain movements, and results of movement, said to be expressive of the emotion "anger." Sir Charles Bell,* in his sixth essay, when speaking of laughter, says, "We have seen that the muscles which operate upon the mouth are distinguishable into two classes — those which surround and control the lips, and those which * Op. eit, p. 146. LAUGHTEK. 53 oppose them and draw the mouth widely open. The effect of a ludicrous idea is to relax the former, and to contract the latter; hence, by lateral stretching of the mouth, and a raising of the cheek to the lower eyelid, a smile is produced. The lips are, of all the features, the most susceptible of action, and the most direct indices of the feelings. If the idea be .exceedingly ridiculous, it is in vain that we endeavour to restrain this relaxation, and to compress the lips. The muscles concentrating to the mouth prevail, and become more and more influenced; they retract the lips, and display the teeth. The cheeks are more powerfully drawn up, the eyelids wrinkled, and the eye almost concealed. The lachrymal gland within the orbit is compressed by the pressure on the eyeball, and the eyes suffused with tears." Here an exceedingly ludicrous " idea " is spoken of as an antecedent and cause of certain movements of the face and other parts. Movements have been shown to be expressive of emotions ; anything which indicates the movement is equally expressive of the emotions. When we look at a watch, we are quite satisfied that the spring and the train of wheels are in motion if we see the movement of the hands, because moving of the hands is necessarily a result of the movement of the wheels within, and nothing else could cause the hands to move continuously. In many cases the results of movements are equally expressive with the movements themselves; it may be that the result of movement is more 54 PHYSICAL EXPRESSION. noticeable than the movement itself. In describing the expression of anger we speak more commonly of showing the teeth, than of retracting the lips, but of course the teeth are shown by movements of the lips. In the expression of rage or anger, Bell describes the visage as sometimes turgid, dark, and almost livid ; this congestion is a secondary result of spasmodic contraction of the respiratory muscles of the larynx, accompanying the clenching of the teeth, leading to a condition of asphyxia. Showing the teeth, and lividity of the countenance, are, then, secondary results of movements, and are direct ex- pressions of the condition of the individual. The voice is another important mode of expression of the emotions by the results of movement. Dr. Foster,* in speaking of special muscular mechanisms, says, " A blast of air, driven by a more or less pro- longed expiratory movement, throws into vibrations two elastic membranes, chordae vocales. These im- part their vibrations to the column of air above them, and so give rise to the sound which we call the voice." Alterations in the tension and position of the vocal cords, and variations in the movements of the respiratory muscles, cause the changes in the voice which are expressive of the emotions. Darwin f gives the following examples of expressive sounds produced by animals through the action of apparatus that cannot be called in any sense " vocal," because not dependent on the respiratory apparatus: "Rabbits stamp loudly on the ground as a signal to their com- rades; and if a man knows how to do so properly, he • " rhysiology," p. 527. f " Expression," p. 93. SECONDARY MOVKMENTS. 55 may, on a quiet evening, hear the rabbits answering him all round. These animals, as well as some others, also stamp on the ground when made angry. Porcupines rattle their quills and vibrate their tails when angered; and one behaved in this manner when a live snake was placed in its compartment. The quills on the tail are very different from those on the body : they are short, hollow, thin, like a goose-quill, with their ends transversely truncated, so that they are open ; they are supported on long, thin, elastic foot-stalks. Now, when the tail ia rapidly shaken, these hollow quills strike against each other and produce, as I heard in the presence of Mr. Bartlett, a peculiar continuous sound." Secondary movements may be expressive without producing sound. Tossing of the head is often very expressive in a girl; the movement, slight in itself, is rendered more conspicuous by the secondary movements of her long curls. So the horse when neighing shakes his mane, and tosses it in the air — movements which express freshness and vigour. A man in prostrating himself on his face bends his body forward by a voluntary move- ment, till the centre of gravity of his body is in front of his base of support, then the body falls, not as the result of a further voluntary effort of movement, but as the consequence of the action of gravity. The first part of this movement is voluntary, and is therefore expressive of volition ; the latter part of the movement of prostration is solely the result of gravity. Work done is a necessary result of movement of 5(5 PHYSICAL EXPRESSION, any kind, but we need not here stop to enter upon that philosophical problem which depends upon the law of the conservation of energy. Work done as the result of movement is positive proof of the move- ment having occurred, therefore work done is the result of the activity of the agent that produces it. It follows that work done may be just as good an expression as is movement. This is an important principle of expression, and different examples must be examined. A certain amount of labour may be performed by a man, such as raising water from a well to a high cistern by means of a pump, or a certain area of land may be dug over in the day's work ; the amount of energy spent in this labour will be some kind of expression of the man's brute strength. The number of pages of writing ac- complished by a literary man is some expression of his mental toil. A fine work of art, painting, or sculpture is the expression of capacity in the artist, and it is also an indication of the quantity of his exertion in a given time. One efiect of movement in man and animals is to produce locomotion; locomotion is work done by movement. If all movements may be expres- sive, locomotion may be expressive of the quantity, time, and kind of work done. Is not the manner of a man's walk often highly expressive? In a man the manner of walking is characteristic of the individual. We may also find types of walk. There is the man whose rapid strides indicate his excitement, and the slow and dawdling walk indicative of purposeless aim. The step may be STUDY OF POSTURES. 57 heavy, irregular, impetuous, or hesitating; it may- be brisk, free, unrestrained, easy, and mobile. A posture of the body is the result of movement. The term "posture" indicates the relative position of the several members of the body with regard to one another, or the relative position of the individual parts of a member. When I began to make a definite clinical study.of expression, in the sense in which the subject is treated in this work, I frequently looked at my patients after diagnosis had been made, to observe if there were any outward ex- pressions of their organic or nerve-condition. My attention was soon attracted to the frequence of certain postures of the body indicative of conditions of the nerve-system. In these early studies it was found more easy to give an accurate description of a posture than of a movement, because a posture is a condition of quiescence, a movement is of temporary / duration. A posture is described when we have ■ given an anatomical description of it, and the matter is more simple to deal with than a move- ment. In works of art, both painting and sculpture, it is very largely by the posture of the body that we judge of the condition of the man or animal represented. These matters are fully considered in chaps, viii., ix., and x. Now, a posture, while it is maintained, implies absence of movement in the part. When we see a man's fist clenched in passion, we may study the posture of that hand, and, as long as it is maintained in that posture without altera- tion, there is no movement of the parts of the hand. A posture is the result of the last movement, and it 58 PHYSICAL EXPRESSION. remains till the next movement occurs. Postures are expressive as the results of movement, and absence of movement is essential to the absolute equilibrium of the posture. We now have to look at examples where absence of movement is a mode of expression, in contrast with others where movement is present. Expres- sion may be produced by the absence of movement, as well as by movement observed. A child, after the day's work and play, is put to bed : we observe a total subsidence of voluntary movements, the eyes are closed, the muscles of the limbs relaxed, no reflex actions occur from moderate light or sound, but the respiratory movements continue with regularity ; then we say the child sleeps. The sub- sidence of movement, other than the respiratory movement, is the principal indication of the con- dition sleep. A man, wearied by the bodily or mental toil of the day's occupation, sits in a chair, he moves and speaks but little, his attention is but slightly attracted by objects around ; it is with difficulty that he is stimulated to movement by the voices of his children; we say that such a condition in the man expresses his fatigue and exhaustion. After rest and refreshment his expres- sion is different, he moves with briskness, he talks to those around, he is quick to observe all about him, he plays with his children and joins in their games : here the man's movements, and the results of his movement, indicate his freshened activity. The absence of ordinary movement may be due to other causes than exhaustion. Watch a hearty MODES OF EXPRESSION BY MOVEMENXa 59 child, say two years of age, sitting on the floor with playthings around him : his movements are incessant, his head, face, eyes, hands, fingers, etc., are incessantly moving. If a stranger enters the room the child stops his play, his various move- ments cease, his eyes are cast down, scarcely any indication of his former condition of movement remains. These is no reason to suppose that the general conditions of his nutrition are interfered with, for the circulation and respiration continue as heretofore. His various movements are arrested or inhibited at the sight of the stranger, and this inhi- bition of movement is characteristic or expressive of the child's condition. When any object strongly attracts the attention of a man it usually produces inhibition of movements. This is probably a very important factor in some mental phenomena. Nutrition may be directly expressed by move- ments, for it commonly happens that movement is the most obvious outcome of nutrition in a subject. A young infant is full of movement while awake, if its nutrition is good; its arms and fin- gers are moved apparently spontaneously.* A baby thus lively is well nourished. Clinical experience shows that the condition of its nutrition is in part indicated by this spontaneous movement. Now, if the child becomes ill, say from the effects of bad feeding, from lung or stoiiiach disease, the spon- taneous movement described almost ceases, the lowered condition of nutrition lessens the amount of spontaneous movement. A large amount of • See obap. xiv. flg. 31, p. 245. 60 PHYSICAL EXPRESSION. spontaneous movement is equally indicative of good nutrition in animals. Note the frisky play of puppies and kittens. The sickly dog, whose nutri- tion is greatly impaired, can hardly lift a paw or wag his tail In some pathological conditions movement may be in excess, and not indicative of a good con- dition of nutrition ; but it will not be convenient to enter upon the discussion of this matter at present.* In speaking of the modes of expression by move- ment, we can hardly be permitted to pass silently over the consideration of the difference between spontaneous and voluntary movements, but it must be remembered that we are not here directly con- cerned with the essential properties expressed by the objective signs. My reason for passing over so important a point is that a discussion as to the criteria distinguishing spontaneous from voluntary movements would involve us in a philosophical argument out of place in this work. Having care- fully considered this point, I have come to the con- clusion that, in place of attempting to distinguish between spontaneous and voluntary movements, it will be easier and more satisfactory to study inborn, and acquired sources of movement. Movements seen to occur upon birth and soon after, may be assumed to depend upon inborn conditions, causes inherent in the subject at birth, so that such move- ments may be called inborn movements. As previously said, the child upon birth presents very constant movements, which may be conveniently spoken of as inborn in contradistinction to the * See chap. vii. p. 125. INBOBN AND ACQUIRED MOVEMENTS. 61 acquired and voluntary movements of adult age. The great distinction between the inborn and acquired movements in kind, is that the acquired movements are found in each successive year of the child's life to be more and more co-ordinated ; they become more easily co-ordinated into complex arrangements by the temporary action of some external force. , I have, at present, but little exact and scientific knowledge as to the differences in kind between the inborn and the acquired movements, but this does not prevent us from considering the question ; and the consideration and discussion maybe an encourage- ment to the investigation of the problem by scientific methods. The expression of inborn properties, as distinguished from acquired properties, is a very important and interesting subject. In an investiga- tion for the purpose of determining what movements are inborn and what acquired, it would be necessary to observe the spontaneous movements of young children,* also to observe what reflex actions can be excited in them, and compare these movements with analogous conditions in later life. These questions, were we conversant with them, would supply some information as to the modes and processes of evolu- tion in the individual and in a species ; we should also gain further knowledge as to expression by co-ordinated movements, a kind so very cha- racteristic of mind. This subject will be further developed and defined in chap. v. and further explained and illustrated in chap. vL • See chap. xiv. 62 PHYSICAL EXPRESSION. Expression of the relations between two or more subjects may be effected by the movements of some kind of intermediate agent, some kind of movement between the subjects that is an expression of the condition of either. If we look at a bank of flowers on a fine summer day, we observe the bees flying from flower to flower. Usually a bee visits only one species of flower in the same journey, and his move- ments indicate something about himself and about the flowers — a relation between bees and flowers that has been well put forward in the writings of Springel, Kerner, and Darwin. Looking at an ants' nest a wonderful order may be obsei-ved in the movements of the little creatures, each appearing to perform its own part in an organized system which appears to be arranged for the benefit of the whole community and not of the individuaL It is the movements of the ants and the work accom- plished by them which indicates the organization of the whole, and the so-called instinctive properties of each. In life in a city we see men pass from house to house, from home to office, etc., these movements, as observed, proving social organization dependent upon the make of each man and the relation of men to one another. When we learn of the movements of an army in the field, and hear how the different portions separated from each other, work in unison for the accomplishment of one end, we find that the relation of the movements of the parts form an expression of the government of the whole. Now, this mode of expression by move- ments is one of the highest which we have to con- SUMMARV. 63 aider, involving, as it does, many subjects, and many forces. Still, the detailed consideration of each of the examples given shows the possibility of under- standing what is expressed by the movements in each case. A bee visiting flowers expresses certain relations between these subjects. The bee is acknowledged to be impressioQable, to be guided to the flower by the sight of the flower, i.e. by the light reflected from the flower. The light reflected from the flower, acting upon the impressionable bee, directs its flight and movements. Is the flower impressionable ? Is the flower affected or impressed by the insect at its visit ? It is certain that variations in plants, and in their flowers in particular, do occur, fitting them to the visits of particular insects. Are these adapta- tions solely due to spontaneous variations preserved as being the fittest ? Is not the modification of the flower helped on by each visit of the insect, to which it ultimately becomes so well adapted ? In conclusion, let me quote from a speech by Sir William Gull * : " A tone of the voice, the play of the features, the outline and carriage of the body, are to him (i.e. the physician) as invariably related to the central conditions which they reveal, as are the grosser facts of Nature." Summary. — Movements in a child may express that it can see and hear. Movement as a mode of expression is particularly worthy of study. It is capable of measurement in time and quantity, and can be recorded by the graphic method ; the records can ♦ Inaugural address, International Medical Congre3B, 1881. 64 PHYSICAL EXPRESSION. be analyzed ; further, all movement can be correlated with other modes of force. For these reasons it is urged that kinetic function, as well as trophic function, should be studied in all living beings. Any movement teUs us something about the source of the motor force, which in man is the central nerve-system. The results of brain-conditions, called the emotions, are expressed by movements ; this may be illustrated by quotations from the writings of Sir C. Bell, Bain, and Siddons, in their descriptions of laughter and anger. Anything that indicates movement may be as expressive as the movement itself. Movement in the hands of a watch indicates the movement of its wheels. We say that in anger a man shows his teeth; we really mean that he opens his mouth and moves his lips. In the expression of rage, the congestion of the face results indirectly from fixa- tion of the respiratory muscles. So the voice results from movements, and is a mode of expression. Similarly, work done is a result of movement, and may be a mode of expression, whether the work be mechanical or mental in kind. The gait in walking indicates a man's general condition, eager- ness, excitement, fatigue, etc. ; it depends upon the condition of his nerve-centres, and expresses this. A posture is the result of the last movement of the part. The significance of postures is shown in chap. vii. The subsidence of movement may be as suggestive a mode of expression as its occurrence. Spontaneous MOVEMENTS OF A BEE AMONG FLOWERS. 65 movement is lost in fatigue, and in exhaustion. The spontaneous movement of infancy subsides in sleep, and on the occurrence of organic disturbance. In certain cases, the movements of two or more independent subjects, not connected by any material link, are expressive, as the movements of a bee from flower to flower, or the movements of men in social life. • 66 PHYSICAL EXPBESSION. CHAPTER V. MOVEMENTS AND THE RESULTS OF MOVEMENTS CONSIDERED IN THE ABSTRACT, OR APART FROM WHAT THEY EXPRESS. Movements are means of expression — ^Movements classified as reflex, voluntary, spontaneous— The attributes of a movement are its quantity, kind, and time — Time of a movement most conveniently recorded by the graphic method — Frequency and duration, the importance of considerations as to time — Two movements, considered in relation to time, may be synchronous ; this may depend upon an organic union of the motors, or upon each working in similar rhythm — Expression may consist of coincidences or combinations of movements — The number ot possible combinations of synchronous movements of » subjects is 2»; the number of sequences of such combinations is unlimited — Actions described as a series of movements — Description of a dog in terms of movement and growth — Co- ordinated and inco-ordinated movements — Walking described as a series of movements — Movements of an aggregation of independent individuals —Principles of analysis of movements —Description in anatomical terms— Contrast of movements of small parts and large parts of the body in their physiological significance — Interdifferentiation — Collateral differentiation of parts — Symmetry of movements, indicating like action on both sides of the brain — Asymmetry of movements common in the higher functions — Classification of movements : according to anatomical analysis ; according to the physiological principles of analysis given above; as intelligent and non-intelligent ; as synchronous or non-synchronous; as occurring in regular series ; as accompanied by feelings, other classifications are suggested — Summary. Movement as a metaphysical abstraction we need KINDS OF MOVEMENT. 67 not consider ; movement as a property of the subject considered is what we are here concerned with. In this chapter we commence with the admission that movements may be expressive, an admission which leads us to study movements apart from their cause, for the sake of simplification of the subject. Movements of various kinds are the principal modes of expression, as is illustrated in the fore- going chapter. Indeed, it is probable that it may be shown hereafter that expression by coincident development * is only a mode of expression by the results of molecular motion. Movements may be classified according to their mode of production, or our ideas thereupon ; thus, in a man, certain movements are said to be spontaneous, others reflex, others voluntary. Again, the classification may be made according to the attributes of the movements — kind, quantity, and time ; which latter attribute includes frequency, speed, duration. Other movements may be con- tinuous or interrupted, and they may be considered in one or in more subjects. As to the movements of a single subject. In all physiological work any calculation concerning move- ment is best made by recording such movement on paper by some graphic method. Now, in looking at a tracing thus produced, we ■see certain indications in the form of the outline of the curves ; if the record- ing paper always travels at one uniform rate, the form of the outline will be plainly characteristic of the kind of movement observed in the same subject * See chap. xvi. 68 PHYSICAL EXPEESSION. on different occasions. Thus the regular move- ments of the heart give a regular tracing on paper ; tracings obtained by movements of the fingers in chorea are most irregular. By "the frequency of movements" we mean the number of observable movements in a minute or other division of time. The term " duration of movements " is self-explana- tory. " Kate " or " speed " implies the degree or length of movement accomplished in a given time. The term " quantity of movement " is used in the sense of quantity as correlatable with other modes V fX^ Chorea flexor movements Fig. 2. of force, as used in speaking of the law of conser- vation of energy. These considerations regarding movement show at once how important time is as an attribute of a movement. Now, if two or more movements be considered in relation to time, further points arise expressive of the relation between the times of the one movement and of the other. Two movements may be syn- chronous throughout, as when two trains run on lines side by side, and start at the same time, and continue to move at the same rate. If two men run in concentric circles at the same rate the movement EXPRESSION BY MOVEMENTS. C9 of their bodies is synchronous, and they maintain their same relative positions; if their rates are unlike, one gets an advance of the other, but after a while they meet again, and the times of the suc- cessive meetings or coincidences is a calculable matter if the rates of movement are known. Turning back from these abstract considerations to our proper subject, expression by movements, a few examples will show how the one bears upon the other. In discussing one mode of expression of the hands, we say, " The fingers of the hand are opened and closed in rapid sucession, indicating the excited and angry feeling of the man." Now, here the movements of five subjects, five digits, are said to coincide, they move synchronously, opening and closing. Now, such synchronous movements may result from the equal pace at which each finger tends to move, or they may result from an organic connection between the cause of each movement. The same facts of movement may be differently expressive, according to the causation of the syn- chronous action. Problems may arise, then, in considering modes of expression, in which the ex- pression is described in terms of coincidences or combinations of movement. A series of movements may occur in any one subject, or, considering two or more movements as regards their time, a series of combinations may occur in definite sequence. The number of possible combinations of synchronous movements is strictly limited by the number of movements considered ; if the number of movements considered be n, the number of possible synchronous 70 PHYSICAL EXPRESSION. combinations of such movements is repi-esented by 2n ; the number of variations in the order of the sequences is without limit, or infinite. As an illustration, consider the movements of the five fingers. Let the five digits be respectively re- presented by the letters A, B, C, D, E, and let us consider the combinations in which they move together. There are thirty-two possible combina- tions of such movements, viz., A, B, C, D, E, AB, AC, AD, AE, BO, BD, BE, CD, CE, DE, ABC, ABD, ABE, ACD, ACE, ADE, BCD, BCE, BDE, CDE, ABCD, ACDE, ABCE, ABDE, BCDE, ABCDE, ; but the number of possible variations in the order of sequence of combinations is infinite. These facts illustrate how the number of postures of the hand, i.e. coincident positions of its parts, is finite, but the variations of expression by variation of its movements are infinite. Many acts or actions may be described by recording the movements, combinations of move- ments, and sequences of movements. A clear understanding on this point is essential to many of the arguments to be brought forward in this work, especially to understanding the importance attached here to the accurate and detailed study of movements, and the fuU appreciation of what such studies may teach us as to methods of investigation, and the methods of evolution. Analogies will be made hereafter between combinations and sequences of trophic action, and of movement. In order to make our ideas more clear we will take one illustration in some detail. GROWTH AND MOVEMENT. 71 The puppy of a setter-dog at its birth is a very different animal from what it is at an adult age. The difference between the two stages of growth would at once strike any ordinary observer, and, if he analyze and arrange the points of difference, he will find differences in size, form, proportions of the body ; also differences as marked in the behaviour, running, steadiness, and kind of work done, i.e. dif- ferences in the kind of movements done and the results of movement. Thus analyzing the points of difference between the puppy and the full-grown dog, it will be seen that it is as important to describe the movements as an expression of the difference between youth and maturity, as to describe the changes in the body alone. Further, there are other changes in function in the animal as the puppy grows to be an old dog ; the conditions of its movements change, and its body, its corpus, changes independently of its movements. There is seen, then, an alteration in two kinds of functions, or properties, as the animal grows old : first, a change in the functions of movement ; second, a change in its trophic condition. A complete historical account of the growth or change of a puppy into an adult animal requires the description of the changes in the conditions of its movements and the differences in its trophic conditions, or growth. It is very usual to speak of the important differences between co-ordinated movements, and inco-ordinated movements. In this chapter we have nothing to do with the causes of co-ordination 72 PHYSICAL EXPEESSION. of movements in man or in animals, but we have to establish rules by which we may dis- tinguish the co-ordinated from the in co-ordinated movements. When a man walks steadily along a road we see that his movements are regular, there is a similar repetition of events, and similar impressions are left at equal intervals upon the dust of the road ; such a man's movements in walking are said to be co-ordinate, and the regularity in the successions and combinations of his movements, as indicated by the general regularity of the move- ments of his whole body and the uniformity of his foot-prints, indicates to us the perfect co-ordination of his movements in walking. Contrast the movements of such a good walker with those of a man afflicted with the condition termed locomotor ataxy, and contrast the foot- prints left by the two men. In locomotor ataxy the patient walks with a precipitate gait, and staggers, the legs start hither and thither vaguely, and the heels come down at each step as in stamping. Such movements are said to be inco- ordinate. Our present object is to inquire how we can best define and formulate what we mean by co-ordination. This, I believe, can only be done with scientific exactness by definitions framed in terms of combinations and successions of move- ments and results of movements. Locomotion, or walking, has been described and experimented upon in man by M, Marey.* He says, " The most simple and usual pace is waUcing, * " Animiil Mechanism," p 111. ANALYSIS OF WALKING. 73 which, according to the received definition, consists in that mode of locomotion in which the body never quits the ground. In running and leaping, on the contrary, we shall see the body is entirely raised above the ground, and remains suspended during a certain time. In walking, the weight of the body passes alternately from one leg to another, and as each of, these limbs places itself in turn before the other, the body is thus continually carried forward. " This action appears very simple at first sight, but its complexity is soon observed when we seek to ascertain what are the movements which occur in producing this motion." This shows us that we may define walking as a succession of paces. " A pace is the series of move- ments executed between two similar positions of the same foot." Now, a series of movements implies something tolerably simple. Marey tells us, then, that walking is a succession of paces, that a pace is a series of movements. It remains, then, for us to inquire what properties may be presented by a series of movements. Walking may be described in various ways. As proposed already, it may be described as a series of movements of the parts (limbs) which produce the locomotion; as a series of muscular contractions moving the limbs ; or, did we possess sufficient knowledge, we might describe a pace in walking by stating what nerve-centres are in action coinci- dently, and what is the order of their successions. M. Marey has in part described locomotion by 5 74 PHYSICAL EXPRESSION. indicating the movements of the trunk in walking as resulting from the movements of the limbs, i.e. he describes the movements of the trunk as moved by the limbs, as moved by the muscles, as stimulated by the nerve-centres. If movements occur in a subject it is implied that the parts of that subject can move more or less independently of one another. When we say a man's limbs move, it is implied that his limbs are movable. If a billiard- ball upon a table is struck and moves in conse- quence, the ball as a whole travels, the movement that follows is that of the whole ball. In speaking of movement it is, then, necessary to be clear whether we are speaking of movement of the object as a whole, as when we speak of the movements of the moon, or whether we mean movements of the parts of the object, as movement of the limbs of an animal It often happens that a certain movement that is observed, is the movement of an aggregation of independent individuals. Such is seen in a pro- cession of men assembled for a political purpose. The movement of the whole procession is an aggre- gation of the actions of a number of separate men, held together and governed for the time by a common political object ; there is no structural union between them : and in such a case the coincidence of their movements is an expression of the bond of union. The movements of such an aggregation are often highly expressive, the more so from the fact that there is no organic union between the individuals. The movements of an army corps are more expres- sive than the movements of a gang of slaves chained ANALYSIS OF MOVEMENTS. 75 together — the cause must be stronger which governs the body of free men. The movements of an army may be expressive of the condition of army disci- pline, the will of the general, the orders of the Home Government, acting under the influence of Parliament and the nation. In any example of expression by movement it is, then, necessary to distinguish actiion of an aggregation of separate individuals from a collection of organically united individuals. Man is the special subject with whom we are concerned, and I wish now to put forward a brief scheme for the analysis of movements seen in man ; this scheme is founded upon experience in medical practice. When we see movements in a man, we may pro- ceed to define them * in anatomical terms. Thus, if a man holds out his arm and hand straight and level with his shoulder, any movement in the parts is easily observed. A movement may be seen to occur, and may be indicated by the following terms : Flexion of wrist, flexion of all the metacarpo-pha- langeal joints, strong flexion of the thumb at each joint, the thumb being thus brought into the palm of the hand with the fingers bent over it ; phalanges adducted, metacarpal bones adducted, thus arching the palm of the hand. Here we give an anatomical description of a movement that might be observed. It is necessary in making an observation, to record the movement, or series or combination of movements, thus, before * See tiibles of analysis, chap. ix. 76 PHYSICAL EXPRESSION. any attempt can be made at analysis or classifica- tion; and we must keep a record of the move- ment before us while we seek explanation of the phenomena and try to understand what is expressed by the movement. After making an anatomical description of the movement for the sake of keeping it before us as a mental account of the transient phenomenon, we may apply certain physiological priticiples to the analysis of the record of the movement. It is well known to physicians that there is much practical difference in the signification of raove- ments in larger parts of the body of vtian in contrast with movements seen in the smaller parts* It is necessary in a compound movement — a general movement, compounded of the movements of dif- ferent parts or subjects — to distinguish in descrip- tion the action of small parts, such as the muscles of the eyes, face, fingers, from movements of larger parts, such as the skull, the shoulder, elbow or wrist, the hip or the knee. This principle of the difierent physiological signification of the action of small and large parts wiU be illustrated in chaps, vii. and viii. ; so also with the other physiological principles. I think there is a considerable importance in the two next principles, though I believe they have been less generally studied than they ought to be. These principles I name " Interdifierentiation " and " Collateral Differentiation." The term " inter differentiation of m^ovem^ents" is * See chap. vii. " Small parts " are most affected in hemiplegia. PHYSIOLOGICAL PRINCIPLES. 77 used to indicate that the conditions of movements are different in the large and in the small parts. There may be a great difference observed, in the upper extremity of a man's arm, in the amount of movement, or in the number of movements of the small parts as compared with the large parts. Thus, in writing, painting, sewing, the fingers, knuckles, and wrist do alijiost all the movements, there being comparatively little action in shoulder and elbow : here, then, is marked interdifferentiation of the movements of the upper extremity. Contrast this example with the use of a man's upper extremity for ground-digging or boxing. In this case the fingers and small parts are but little used, the move- ment is from shoulder and elbow; here, again, inter- differentiation of movements is marked in degree, the large parts being more used than the small parts. Collateral differentiation of movements, or a dif- ference in the movements of collateral parts, is our next principle. The knuckles and the fingers are collateral parts: they are all equally small parts, they can move all together or each can move sepa- rately. There may be differences in the movements of the fingers, or collateral differentiation of move- ments may be seen. In writing, the movements of the pen are effected almost entirely by the thumb, index, and middle fingers : this is collateral dif- ferentiation of the movements of the fingers in the act of writing. Symmetry of movement in man and in animals is by no means a new subject; it has been noted 78 PHYSICAL EXPRESSION. and often discussed. I think that symmetry of movements, in a physiological sense, indicates equal bilateral movements, movements occurring similarly on either side of the body. The physio- logical importance of symmetry is very different in various parts of the body : the expression indicated by a symmetry of hands is very different from the signification of a symmetry of the tace. Here we may stop one minute, again to point out an analogy between conditions of movement and conditions ot trophic action. Symmetry of movement and sym- metry of growth and structural development are seen in man in the nutritive organs, lungs, and respiratory movements; the two halves of the brain in their anatomical structure and the two sets of nerves with organic functions, vagi, phrenics, sympathetics, are fairly symmetrical. Asymmetry in man chiefly concerns his higher functions ; it is seen in his movements in writing, and other high-class hand-work. Speech is not equally represented in either hemisphere of the brain. Some passions are expressed asymmetrically in the face. Evolution is often expressed in plants by asymmetry of growth (see chap. ii.). Classification follows naturally after analysis. I have purposely omitted to consider all the means of analysis of movements, as such might prove weari- some, and is hardly necessary to clear views on the general subject of this work, " The Modes of Expres- sion," For the same reasons our notice of classifica- tion will be but brief, but both analysis and classi- fication will be abundantly illustrated in succeeding CLASSIFICATION OF MOVEMENTS. 79 chapters. In any special problems as to a mode of expression and its meaning, it is ot course necessary to use all methods of analysis, and also to see in what class the special mode of expression under consideration is to be placed. The following classifications of expressive move- ments are suggested as practically useful : — 1. Anatomical analysis gives a method of classi- fication; the same anatomical movements will always appear in the same class under this arrange- ment. It must be understood, however, that similar movements have a very different signification under difierent circumstances. Closing the fingers when grasping an object, when in passion, and in an epileptic fit, may be a similar movement, but the signification varies in each case. 2. Movements may be classified according to the physiological principles given. 3. Movements are often spoken of as intelligent and non-intelligent. This division is difierent from those used above, and does not depend solely upon their analysis ; their signification depends upon the previously ascertained truth, or uniformity, that certain kinds of movement are only produced by a central nerve-mechanism which can also produce " intelligence " or non-intelligence at the same time as it produces the particular movements in question. Good-class painting, high-class manipulations are expressive of intelligence, because they are uni- formly found to accompany intelligence. Walking is not necessarily accompanied by intelligence : a man may walk in his sleep, an idiot may walk. 80 PHYSICAL EXPEESSION. Again, sucking in an infant is not a sign of present intelligence. Some movements are usually accom- panied by non-intelligence. 4. Movements may be synchronous or asynchro- nous. 5. Movements may be classiiied as occurring in a regular series. The regular movements of a particular dance may be expressive. A series of movements is often expressive of certain passions, emotions, or states of feeling. In some kinds oi fits a series of movements characterizes the attack. 6. Movements are often spoken of as caused by feelings. It seems to me that this is a great assump- tion. It may be, on the contrary, that the move- ment and the feeling are alike due to the condition of nerve-centres. Summary. — For the sake of simplicity movement is here considered apart from the cause of that movement which it directly expresses. Various modes of classification of movements may be used — as spontaneous, reflex, voluntary; this classification depends upon our idea of their origin. A classifica- tion may be made according to the attributes of the movement — frequency, speed, duration, quantity, etc. The graphic method is most suitable for such a classification. Further, description of the attri- butes of a movement involves consideration of the analysis of tracings of movements; the considera- tion of the attributes of a movement involves the laws of conservation of energy, also ideas of the relation of time, and quantity. When the relations of two or more movements are SUMMABY. 81 considered, intricate mathematical problems arise which are probably more complicated than ques- tions in astronomy. The possible number of combinations of movements is finite, as is easily illustrated. It appears probable that a very direct analogy may be made between series of movements, and series of acts of growth, and that similar laws may govern b(jth. 82 PHYSICAL EXPKESSION. CHAPTER VL PHYSIOLOGY OF EXPRESSION. Modes of movement in plants ; in the amoeba ; the aseidian has a nerve-mechanism, and apparatus for reflex movements — Nerve-meohauism of vertebrates — Nerve-muscular apparatus ; nerve-muscular action — Do certain nerve-centres produce certain movements ? — Ferrier's experiments — Cerebral localization — Nerve-centres — Visual perception indicated by movements — Time requisite for a reflex movement — Inhibition of move- ment — Physiological effects of light, in man, in plants — ^Light stimulates trophic and kinetic action — Effects of light in the new-born infant; movements stimulated, inhibited, co-ordi- nated — Eetentiveness to effects of light — -The brain of an idiot not thus ImprcBsiouable to light — Summary of the effects of light — Extrinsic stimuli, mediate and immediate — Trophic action of light — Summary of effects of light on plants. In dealing with the physiology of expression we are concerned solely with facts in the history of living beings, plants and animals, including man ; the sections of physiology that we are mainly con- cerned with are those involving questions of move- ment and nutrition. It is convenient, then, to our purpose that we should take a brief review of the modes in which movement is produced in the organism of the lower, and higher, living beings. Something has been said in chap. ii. about the THE AMCEBA — THE ASCIDIAN. 83 causes, and the mechanism of movement in plants. In animals we see movement result from the action of the organism as a whole, or from the action of parts of it, and this is one of the most constant facts seen in the lowest and highest grades of animals. The movements of amoebae and other protozoa have been often observed. The body of the amoeba is Jess firm than jelly, yet it has the power of moving from place to place. At first appearing as a shapeless mass, it may rapidly throw out filaments, or projections, which may again be retracted into the mass of the amoeba. All parts of this mass appear to be alike, and similarly endued with contractile powers. These filmy patches glide about although the eye can detect no differentiation of their parts, and there is no special mechanism for producing force, apart from the portions that produce movements. In such animals there is no difiierentiation into force-producing parts, and motor-organs ; every part of the body can perform all the functions of the whole organism : thus it is seen that the amoeba has an organization lower than that of the Oxalis and Mimosa pudica, which have special motor- organs. In the ascidian there is a mechanism for the production of motor-power, and a contractile appa- ratus as a moving instrument. " The nervous appa- ratus consists of a central ganglion, Fig. 3 (c), con- nected with the periphery by two sets of nerve- filaments. One set is distributed to a part of the integumentary surface capable of receiving and 84 PHYSICAL EXPRESSION. being acted on by external stimuli (a), the other is distributed to muscular fibres, which on contrac- tion cause diminution of the body cavity (c?). Im- pressions made on the sensory surface are conveyed by the afferent fibres to the central ganglion, Fig. 3. — Nervous system of ftn AscldiaD (Carpenter), a, the mouth ; 6, the vent ; c, the ganglion ; d, the muscular sac. whence an impulse is sent along the efferent fibres, causing contraction of the muscles. Such an action is termed a reflex action, a term derived from the reflection, as it were, of the afferent impression back to the periphery." * The ganglion produces the motor-power ; the muscular fibres are the motor- apparatus, acting when they receive an impulse from the ganglion. Now, passing up to the vertebrates. Here we find a well-defined portion of the body, the nerve- mechanism which, when properly nourished, pro- duces motor-force; there are also well-defined muscles, connected by nerve-fibres with the nerve- centres. When a stimulus passed from the nerve- * Ferrier, op. cit., p. 16. NERVE-MUSCULAR APPARATUS. 85 centres to the muscles they contract, and produce movements. Here, then, in the higher animals, the nerve-mechanism and the muscles produce the movements, and the joint action of these two por- tions of the body is necessary to the production of movements ; this has been proven by numerous experiments in many subjects. The kind of movements that we have to do with in the study of expression in man are nerve- muscular signs, and it is essential to obtain clear ideas on this point, in order that the principles and modes of expression in man may be understood. The simplest nerve-muscular apparatus consists of a muscle, a nerve-centre or collection of nerve-cells, and a nerve-fibre conveying currents from the nerve- centre to the muscle; the whole must, of course, be duly supplied with blood and nourished. Force is generated in the nerve-centre by its nutrition, and is conveyed to the muscle by the nerve-fibre. When the centre sends force to the muscle it con- tracts ; the muscle serves as an index showing the times of discharge of force by the centre. It is not necessary here to give any detailed account of the structure and arrangement of the nerve-centres; suffice it to say they are situated in the brain and spinal cord. It is, then, convenient for our purposes in the study of the principles and modes of expression to speak of " nerve-muscular action " or signs. In the study of the brain and spinal cord we know when a current of nerve-force is sent out from a nerve-centre by the effect of that current on mus- 86 PHYSICAL EXPRESSION. cular fibres. The muscle is the index of the nerve- current ; the muscular contraction is the expression of the motor action of the brain, indicating the time, frequency, duration of the nerve-current produced by the central organ. If the central nerve-system is the organ gene- rating the force, and stimulating the muscles to Fig. 4.— Upper Surface of the Hemispheres of the Monliey. The circles und included numerals are explained in the text (Ferrier). contract, can different portions of that mass act separately ? Do certain parts of the nerve- mechanism stimulate special movements ? Are certain movements indications of the activity of certain parts of the central nerve-mechanism ? Dr. Ferrier experimented upon the brains of dogs and monkeys with the following results : — 87 Figs. 4 and 5 represent the lateral and upper surfaces of the brain of the monkey; the circles and included numerals indicate certain areas on the convolutions of the brain. Figs. 6 and 7 repre- sent similar views of the human brain, and the circles with their numerals indicate areas corre- sponding approximately with the areas on the monkey's brain, similarly indicated. In his ex- periments Ferrier examined each area in two ways. The portion of brain experimented upon was excited Fig. 8.— The Left Hemisphere of the Monkey. The circlee and numerals have the same significance as in last figure. by an electrical stimulus, and the muscular move- ment in the body which resulted was carefuUy ob- served and recorded ; as a converse experiment, the same brain area was then destroyed, and the set of movements in the body which were previously stimulated were now found to be paralyzed. This demonstrated that stimulation of a certain brain area produced a certain set of movements in the body, and that when the same brain area was destroyed, that set of movements was paralyzed. 88 PHYSICAL EXPRESSION. As the result of such methods of inquiry, the fol- lowing list* was drawn up, indicating the brain areas corresponding to certain movements : — Fig. 6. — Upppr Surface of the Human Brain. The circles and letters have the same signification as those on the brain of the monkey (see Fig. 4). "(1), placed on the postero-parietal lobule, in- dicates the position of the centres for movements * The brain-centres referred to in the succeeding paragraphs are indicated in the figures by the corresponding numerals. FEKBIERS NERVE-CENTRES. 89 of the opposite leg and foot, such as are concerned in locomotion. " (2), (3), and (4), placed together on the convolu- tions bounding the upper extremity of the fissure Fig. 1. — Lateral view of the Human Brain. The circles and letters have the same eignificatlon as those in the brain of the monkey (see Fig. 5). of Rolando, include centres for various complex movements of the arms and legs, such as are concerned in climbing, swimming, etc. " (5), situated at the posterior extremity of the 90 PHYSICAL EXPRESSION. superior frontal convolution, at its junction with the ascending frontal, is the centre for the extension forwards of the arm and hand, as in putting forth the hand to touch something in front. "(6), situated on the ascending frontal, just be- hind the upper end of the posterior extremity of the middle frontal convolution, is the centre for the movements of the hand and forearm in which the biceps is particularly engaged, viz. supination of the hand and flexion of the forearm. " (7) and (8), centres for the elevators and depres- sors of the angle of the mouth respectively. " (9) and (10), included together in one, mark the centre for the movements of the lips and tongue, as in articulation. This is the region, disease of which causes aphasia, and is generally known as Broca's convolution. "(11), the centre of the platysma, retraction of the angle of mouth. "(12), a centre for lateral movements of the head and eyes, with elevation of the eyelids and dilata- tion of the pupil. "{a), (i), (c), and (d), placed on the ascending parietal convolution, indicate the centres of move- ment of the hand and wrist. " Circles (13) and (13'), placed on the supra-mar- ginal lobule and angular gyrus, indicate the centre of vision. "Circles (14), placed on the superior tempero- sphenoidal convolution, indicate the situation of the centre of hearing." When we consider that any expression by move- SENSORY CENTRES. 91 ment, or the result of movement, in man or in an animal, is an indication of activity in the central nerve-system, and is probably due to the activity of a certain part only, we find it convenient to recognize this in our nomenclature. The term nerve-centre is here used to imply a portion of the nerve-mechanism, which can act more or less independently o£ the rest, and which by its activity produces certain, more or less definite motor or other efiects, observable and separable from those of the rest of the central mass of the nerve-mechanism. This paragraph implies the belief that there are nerve-centres, as above defined, existent in the brain. Ferrier's experiments and numerous other facts tend to support that view. In speaking of nerve-centres in the brain, we do not here wish to express the belief that these necessarily exist as localized anatomical areas of brain tissue separate irom the surrounding nerve- mechanism, although this may be true. I think that we have framed a definition without implying such anatomical isolation as an essential fact. An hypothesis is useful, if it leads to systematic experimentation and the record of observations, and I trust to be able to show that qertain pro- positions may be defined and investigated by means of this working hypothesis that nerve-centres do exist as defined above. In Ferrier's * experiments the sensory centres in the brain were sought for by observing that move- ments, or absence of movement, indicating blindness • Op. cit, p. 165. 92 PHYSICAL EXPRESSION. followed in an animal when a portion of the brain called the angular gyrus was destroyed. "In support of these conclusions, the following details selected from the protocols of the several experiments recorded elsewhere, will be sufficient. In the first experiment the angular gyrus of the left hemisphere was destroyed, the left eye was securely bandaged, and the animal allowed to recover from the state of chloroform narcosis. After recovery it began to grope about a little vn loco perfectly alert, but would not Tnove from its position. It did not flinch when held close to the gaslight. Placed in a cage beside its companions, it took no notice of them, but sat still. Hearing and other senses re- mained unaffected, and stimuli of these senses caused active reaction." The quotation is given exactly; the italics are mine, and it is at once seen that the evidence of blindness was the condition of movements, the kind of reflex action following or not following upon stimulation. This affords further evidence as to the truth of the statement that we are dependent upon the motor functions of the nerve-centres for almost all the knowledge we have as to their functions. Reflex Action. — The apparatus necessary for a reflex action has been briefly described in chap, iii. ; something more must now be said concerning the time consumed in the production of a reflex movement. Foster gives the following experiment {o'p. cit, p. 471) : " If, in a brainless frog, the area of skin supplied by one of the dorsal cutaneous nerves be separated by section from the rest of the TIME REQUIRED FOR REFLEX ACTION. 93 skin of the back, the nerve being left attached to the piece of skin and carefully protected from injury, it wiU be found that slight stimuli applied to the surface of the piece of skin easily evoke reflex actions, whereas the trunk of the nerve may be stimulated with even strong currents without producing anything more than irregular movements. "In every r«flex action, in fact, the central mechanism may be looked upon as being thrown into activity through a summation of the afferent impulses reaching it." The change in the nerve-centre which follows upon the afferent stimulus requires a certain time, and this is proven as foUows : — " The Time required for Reflex A ctions* — When we stimulate one of our eyelids with a sharp electrical shock, both eyelids blink. Hence, if the length of time intervening between the stimulation of the right eyelid and the movement of the left eyelid be carefully measured, this will give the time required for the development of a reflex action. Exner found this to be from -0662 to -0578 sec, being less for the stronger stimulus. Deducting from these figures the time required for the passage of afferent and efferent impulses along the fifth and facial nerves, to and from the medulla, and for the latent period of the muscular contraction of the orbicularis, there would remain '0555 to "0471 sec. for the time consumed in the central operations of the reflex action. The calculations, however, necessary for this reduction, it need not be said, are open to * Foster, op. cit, p. 478. 94 PHYSICAL EXPRESSION. sources of error. Exner found that ■when he used a visual stimulus, viz. a flash of light, the time was not only exceedingly prolonged, "2168 sec, but very variable. "The time required for any reflex act varies, according to Rosenthal, very considerably with the strength of the stimulus employed, being less for the strong stimuli, is greater in transverse than in longitudinal conduction, and is much increased by exhaustion of the cord. It has been stated that the central processes of a reflex action are propagated in the frog at the rate of about eight metres a second; but this value cannot be depended on. The time thus occupied by purely reflex actions must not be confounded with the interval required for mental operations ; of the latter we shall speak presently. "Inhibition of Reflex Action* — When the brain of a frog is removed, reflex actions are developed to a much greater degree than in the entire animal. We ourselves are conscious of being able by an effort of the will to stop reflex actions, such, for instance, as are induced by tickling. There must, therefore, be in the brain some mechanism or other for preventing the normal development of the spinal reflex actions. And we learn by experiment that stimulation of certain parts of the brain has a remarkable effect on reflex action. In a frog, from which the cerebral hemispheres only have been removed, the optic thalami, optic lobes, medulla oblongata, and spinal cord being left intact, a certain average time will be found to elapse * Foster, op. cit., p. 474. INHIBITION. 95 between the dipping of the toe into very dilute sulphuric acid and the resulting withdrawal of the foot. If, however, the optic lobes or optic thalami be stimulated, as by putting a crystal of sodium chloride on them, it will be found, on repeating the experiment while these structures are still under the influence of the stimulation, that the time intervening between the action of the acid on the toe, and the withdrawal of the foot, is very much prolonged. That is to say, the stimulation of the optic lobes has caused impulses to descend to the cord, which have there so interfered with the action of the nerve-cells engaged in reflex action as greatly to retard the generation of reflex impulses ; in other words, the stimulation of the optic lobes has inhibited the reflex action of the cord." The effects of light have been referred to several times as producing marked effects upon the brain- centres, and exerting a stimulating or inhibitory influence. It may then be interesting to review a few of the known effects of light, and the absence of light, upon living things. It is generally admitted that light does produce marked effects upon the human body. We see different phenomena occur in daylight and in dark- ness. Sunlight is most useful in the cure of ansemia, and partial darkness often helps the cure of an acute case of chorea ; in megrim and in ophthahnia the patient is often unable to bear the effects of light. Some of the effects of the exclusion of light from cave-living animals have been .well demonstrated by the author of the " Origin of Species " (see 96 PHYSICAL EXPRESSION. p. 101). The action of light on vegetable organisms, and its eflfects in producing movements of various kinds, have also been carefully studied. I have, therefore, put together the following notes on the effects of light. In such a subject as the present, as in so many- other questions concerning the action of physical forces upon living organisms, it seems to me use- ful to consider the effects of light upon the simple cellular vegetable organisms, where these changes can be studied with much exactness, as well as in animals. The action of light may be roughly described as trophic or kinetic; that is, mainly producing growth, or mainly causing movements and not growth. Take a sample of the human species at the earliest period of possible observation, directly after birth. If we examine a new-born infant, we find that when a light shines upon its face it screws up its eyes (i.e. the orbiculares oculi muscles contract strongly), and it corrugates the forehead (i.e. corru- gators contract). If the eyelids be opened, the iris contracts to light ; in some cases, when the infant is a few days old, there seems to be a tendency to turn the head from the light, i.e. the skuU rotates from a lateral light. The action of light upon the iris needs only to be mentioned. It is commonly admitted that this is a purely reflex act in which the optic is the afferent nerve ; the third, or motor-oculi, the efferent nerve ; and the centre is some portion of the corpora quadrigemina. ACTION OF LIGHT ON AN INFANT. 97 The infant as born has, then, such an apparatus as allows of these two reflex actions to light. Now; in these reflex actions the light excites or stimulates these reflex movements. A plain beam of white light effects this. I do not know the effects of different rays of the spectrum. I am not aware of other effects of light in the infant in its youngest stage, but, at five months old, holding a brightly coloured object well within the field of vision of the infant attracts its atten- tion, as it is said. We see the child's eyes and head move, so as to bring their axes in a straight line towards the object. This is a mechanical effort; there is work done. What force can excite this movement and direct it with such precision ? We know of no force passing from the object to the child, except the light reflected; a screen hiding the object from the child's eyes, i.e. cutting off the rays of light reflected from the object, prevents the object from exerting its effect upon the child. The beam of light reflected from the object excites the movement that follows action of the light ; the effect of the light must penetrate the retina, and travel to the centres for the muscles seen excited to action. A few words must now be said as to the effects of "the sight of objects." When we see an object, all our subjective impressions of that object are the effects of the beam of light reflected from the object; and all the objective, observable effects of the sight of that object are the effects of the excitation, or stimulation, produced by that beam of light. Here, 6 98 PHYSICAL EXPRESSION. again, the beam of light, or its effects, must be transmitted from the retina to the deep centres affected. A lateral light falling upon the field of vision stimulates the opposite hemisphere, and this causes contraction oi the head-rotatory muscles on the side from which the light comes, causing it to be turned towards the light or object seen. Fig. 8.— Hydrophobia, after Sir C Beli. Head repelled by Bight of water. Light acts as a stimulant of movement; con- versely, darkness favours quietness. Strong light dispels sleep. I think it can be shown that the stimulating effects of a beam of light reflected from an object may spread widely among the nerve-centres, producing co-ordinated and organized sequences ACTION OF LIGHT ON BKAIN. 90 of movements ; this is the effect of the visual stimulus. The sight of an object not only produces move- ments of the eyes and head, but also causes such movements in the upper extremity, as result in the hand approaching and grasping the object which reflects the beam of light and excites the movements ; the movements spread to a wide area. The sight of an object that has many times been seen, especially if some pleasure has accompanied the sight, produces a repetition of movements ; the reflex action recurs on the recurrence of the same light stimulus. This indicates " retentiveness ; " it is evidence of the fact that nerve-currents proceed along certain paths when they are produced by a similar stimulus. In all these phenomena a moving beam of light produces more marked efl'ect than a stationary beam ; that is to say, a moving light, a moving object, attracts the most attention. The brain of an imperfect subject may be so constructed as not to give the phenomena described above. The child may not be attracted by the light ; it may, when six months old, not notice or attempt to grasp an object presented. We see that here the central nerve-mechanism is not duly sus- ceptible to the reflex actions of light, and this indicates that it is not normal in its construction. These are some of the methods by which we judge whether a child has such a nerve-mechanism as will probably develop' the due or normal functions of mentation in its after growth. 100 PHYSICAL EXPRESSION. A further example of " retentiveness " to light impressions is seen in similar repetitions of facial expression, following the sight of the same object. One effect of light, then, is to excite, stimulate, or stir up certain reflex actions. A second effect of light is to produce new, not inborn, reflex actions, as indicated by the produc- tion of retentiveness in the nerve-mechanism to the effects of certain light impressions. A third effect of light is to control or modify- previously existing movements. Examples are seen in the effect of the sight of a bright light, or the sight of certain objects, in co-ordinating or arresting spontaneous movements. A light, or the sight of an object, may inhibit movements instead of increasing their amount and frequency (see tracing. Fig. 9). The following phenomena may then be observed as produced by the action of light on man : — (1) Reflex action. (2) Transmitted effects. ( (a) Excitant, (3) Action on spontaneous movements < (6) Inhibitory, ( (c) Co-ordinating. (4) Retentiveness of the effects of light. (5) The evolution or building up of mentation. The action of light may be spoken of as extrinsic, inasmuch as it is a stimulus originating out- side the organism, and producing changes in its structures. In contrast we may speak of the " passions " and " feelings " as intrinsic stimuli, as it may be supposed that they originate in some part of the organism. TROPHIC ACTION OF LIGHT. 101 "S 1^ S Extrinsic stimuli may be — (1) im- mediate in action, as when a body acts by mechanical contact ; (2) me- diate, as when the sight of an object produces a visual stimulus which passes to the subject from the object seen. These mediate influences have sometimes been called sympathies. In the infant at birth, respiration is a mediate reflex act. Air ex- cites the movement in a normally constructed child. Sucking is a re- flex act due to immediate mechanical irritation, and is dependent upon the medulla oblongata. Such actions are called " instinctive." In this sense movements in plants are "instinc- tive," that is, due to their essential construction. As to the more distinctly trophic effects of light. Pigmentation of the skin occurs in the tropical regions when light is strong. Charles Darwin * gives an account of certain cave-living animals whose eyes have, in the course of successive generations, been lost owing to dis- use. " It is well known that several animals, belonging to the most different classes, which inhabit the caves of Carinola and of Kentucky, * " Origin of Species," p. 110. 102 PHYSICAL EXPRESSION. are blind. In some of the crabs the foot-stalk for the eye remains, though the eye be gone ; the stand for the telescope is there, though the tele- scope with its glasses has gone. As it is difficult to imagine that eyes, though useless, could be in any way injurious to animals living in darkness, their loss may be attributed to disuse. In one of the blind animals, namely, the cave-rat {Wotaifna), two of which were captured by Professor Sillman at about half a mile from the mouth of the cave, and therefore not in the profoundest depths, the eyes were lustrous and of large size; and these animals, as I am informed by Professor Sillman, after having been exposed for about a month to a graduated light, acquired a dim perception of obj ects." This fact may, I suppose, be expressed by saying that in successive generations, owing to the want of the stimulation of light upon the parents' eyes, these organs have ceased to be developed in the young. It seems to me that this is equivalent to saying that the stimulating effects of light are necessary, in all probability, to prevent the organs specially suited to receive light impressions and convey them to the nerve-mechanism, from degenerating in successive generations. This is a trophic action of light. The sight of a good dinner has been shown to increase the quantity of gastric secretion. Like- wise the sight of food stimulates the salivary secretion. A woman in good health, after seeing her husband killed (light effect only), took up her infant and suckled it; the altered milk proved poisonous to the child. PHYSIOLOGY. 103 The following table, after Sachs,* indicates the action of light on vegetation : — A. Genebal. (1) Action of rays of different refrangibiiity. (2) Variation in the action of light on plants in proportion to its intensity. (3) Penetration of the rays of light into the plant, B. Special. (1) Chemical action of light on plants, (a) Formation of chlorophyll. (6) The decomposition of carbon dioxide. (c) Formation of starch in the chlorophyll. (2) Mechanical action of light on plants. (d) The influence of light on the movements of protoplasm. (e) Cell division and growth. (/) Action of light on the tension of the tissue of the con- tractile organs of leaves endowed with motion. Light may retard the growth of cells, as in heliotropism. Darwin 1" has demonstrated many facts concern- ing the action of light on plants. * Sachs, " Text-book of Botany." t " Movements of Plants." 104 PHYSICAL EXPRESSION. CHAPTER VII. PATHOLOGICAL FACTS AND EXPRESSION IN PATHO- LOGICAL STATES. Disease may destroy or irritate parts of the brain — Destruction of corpus striatum— Lateral deviation of the head and eyes — Effects of irritation in contrast with destruction of a brain area — Effects of disease on different sets of muscles— Facial palsy — Localization of disease — Epilepsy — Chorea — Analogy to movements in plants — Experiments with the Mimosa — The study of chorea — Finger-twitching in nervous children — Tooth-grindiug — Headaches in children ; the physical signs — Cases of athetosis — Defects of development; their frequent coiaoideuce. There is no intention here to enter upon a de- scription of conditions of disease from a medical point of view, but as direct experiments cannot be made upon the living brain of man, we avail Ourselves of information derived from the rough kind of experiments often prepared for us when conditions of disease destroy or irritate certain brain areas ; we thus observe the effect of de- struction or direct irritation of parts of the brain. In a case of complete hemiplegia, or paralysis of one side of the body, from a lesion destroying part HEMIPLEGIA. 105 of tho corpus striatum of the opposite side, we find the following phenomena : — Complete Hemiplegia from Lesion of the Right Corpus Striatum.* 1. Tho head turns to the right. 2. Both eyes turn to the right, and frequently both upper eyelifls are fallen. 3. The muscles of the belly and chest are weak- ened on the left. 4. The muscles passing from the trunk to the left limbs are paralyzed. 5. The face is paralyzed on the left side. 6. The tongue on protrusion turns to the left. 7. The left leg is paralyzed. 8. The left arm is paralyzed. Such is the combination of movements, and the compound posture, resulting from a destructive lesion of the right corpus striatum. Now, to consider a few of the special movements in more detail. Lateral deviation of the eyes and head — both eyes turn to the right as a result of destruction of the right corpus striatum, and the head turns in the same direction. This is an in- teresting phenomenon for comparison with modes of expression by head rotation (see p. 185).- In the case of a right-sided brain lesion, the head rotates to the right on account of the weakened condition of the left muscles, so that those on the right side pull it over to the non-paralyzed side. * See Dr. Hughlings Jackson in Kuseell's " SyBtem of Medicine," vol. ii., p. 537. 106 PHYSICAL EXPEi;gSION, The eyes turn to the right as if looking at a person on the right side. Thus they do not lose their parallelism ; the axes of the eyeballs remain paral- lel — there is no strabismus. This lateral deviation of the eyes may show the weakness of one side of the brain, and suggests a one-sided lesion in con- tradistinction to a general brain state, such as poisoning by opium. Now, observe the effect of such a lesion of the right corpus striatum (or of the centres which send their fibres through it) as causes convulsion of the parts previously paralyzed. In such a case we generally speak of an irritative lesion of the nerve-centre as producing the convul- sion or spasm, in contradistinction to a destructive lesion which produces paralysis. An irritative lesion of the right corpus striatum causes the head to rotate to the left, and the eyes to deviate to the left, while the left limbs are con- vulsed. Eight Ooepus stbiatdm. Destructive Lesion. Irritating Lesion,, Head and eyes turn to the right. Left limbs paralyzed. That is, head and eyes turn away from the side paralyzed. Head and eyes turn to the left. Left limbs convulsed. That is, head and eyes turn towards the side convulsed. These facts help to give some explanation of cer- tain coincident movements and postures (see p. 151). A destructive lesion on the right side of the brain weakens the left arm and leg, and the head rotates to the right. In an analogous manner we often see the left hand in the nervous posture — a sign of weakness of the right hemisphere of the brain ; and FACIAL PALSY FROM BRAIN DISEASE. 107 this is often associated with rotation of the head to the right, with right inclination (see p. 151). Again, we see that if one hemisphere, instead of being weakened, be excited, causing spasm of the muscles, the head is rotated to the same side as the spasm ; thus the kind of condition of the brain is indicated or expressed by the relative position of the head to the side of the body aflfected. The brain lesion causing hemiplegia does not affect equally all the parts of the upper extremity. On comparing the degree of .power of movement in the fingers and in the arm, we find that though the patient can open and close his hand, and carry it to his mouth, still he cannot use the smaller parts of the hand for fine operations ; he cannot pick up a pin off a wooden table, or unfasten the middle button of his waistcoat. He has lost the power for fine adjustments of the small parts, but has still fair power over the limb in its larger parts. As to the facial paralysis seen in hemiplegia,* all the muscles on the side of the face are weakened, but very unequally ; there is very slight weaken- ing of the orbicularis palpebrarum. The patient can close his eyes, although not so strongly on the paralyzed side when urged to close them both tightly ; sometimes, especially in chronic cases, we discover no difference on the two sides. This cerebral-facial palsy differs from that due to disease of the facial nerve in its distribution. Brain facial palsy weakens mostly the muscles about the mouth. This is seen markedly when the patient shows his ♦ See Figs. 10, 11, and compare with Fig. 27, p. 202. 108 PHYSICAL EXPfiESSION. teeth, or whistles ; the groove running from the nose to the mouth is less marked than on the other side. In studying any case of brain disease, it is very desirable to localize the seat of lesion. The follow- ing are briefly the principles employed in trying to make such 'localization .during the life of the patient. It is impossible to make any scientific Fig. 10. — Right Hemiplegia, -with cerebral facial palsy, right side. The face is asymmetrical, and the muscles in the right lower zone about the mouth act very indifferently. The naso-labial groove on this side is almost lost . this is well seen on comparing the two Bides. Mo asymmetry is seen in the upper and middle facial zones. diagnosis of the locality of the lesion unless some localizing symptoms be present. Now, the main localizing symptoms are paralyses and spasms of the muscles supplied with ipotor force from the nerve-centres affected by the lesion. Destruction of the corresponding mass of brain substance, in different men, whether by haemorrhage or by softening, paralyzes the same muscles in each, and BBAIN FACIAL PARALYSIS. 109 interferes with corresponding movements; hence, when we find one particular set of movements interfered with, we infer the seat of lesion. Similarly, convulsion or spasm in one particular set of muscles indicates the discharge of motor force from the particular set of nerve-centres whose destruction leads to paralysis of that particular Fig. II.— Left Hemiplegia, with cerebral palsy, left side. set of muscles. The irritation causing such a discharge of force may be a tumour, or local in- flammation irritating that portion of brain. Hence coarse or extensive paralyses, and other profound disturbances of the nerve-muscular system, have received much attention from clinical and patholo- gical observers, and by the accumulation of their joint observations much knowledge has been gained 110 PHYSICAL EXPEESSION. as to the symptoms that result from lesion of cer- tain portions of the brain. This encourages us to observe, in all cases of health and disease, the move- ments and results of movement, knowing that these correspond to, and are the direct outcome of, the states of certain nerve-centres. The knowledge that we already possess of the nerve-centres is from observation of muscular action. In a given case, by comparing the state of the muscles during life, as they may be affected by paralysis or spasm, with the brain lesion found after death, and by collecting and comparing many cases, it has been found that destructive or irritative lesions of certain parts of the brain cause paralysis or spasm of a certain set of muscles corresponding. Epilepsy is a chronic disease, characterized by (1) attacks of more or less disturbance of con- sciousness, (2) muscular spasms and convulsions. The careful, detailed, and accurate observation and record of the movements of the convulsion, and sequent paralyses, has proved an efficient means of study in this disease, the movements and results of movements being studied as indices of the action of nerve-centres. Epilepsy is a condition of disease of which we know but little beyond what can be learnt from studying nerve-muscular movements, and their associations and concomitants ; still we do possess much practical and useful knowledge of epilepsy. Chorea is a disease, or abnormal condition, com- monly seen in children. It is characterized by a great excess of involuntary movement, and a vary- ing amount of muscular weakness. The movements CHOREA. Ill cease during sleep ; in kind they resemble gesticu- lations, and in their combinations and successions are probably such as may occur during conditions of health. Each movement probably depends upon a discharge of motor force from some nerve-centre corresponding. Chorea is dependent upon a brain condition which we know only through the effect produced upon 1;Jie muscles by the brain. In children I have often observed that "the weak and nervous " have much spontaneous finger- twitching; and I described this as one of the physical signs seen in children who suffer from recurrent headaches and associated pathological conditions.* Such muscular unsteadiness seems very analogous to the movement of young, grow- ing, sensitive vegetables. The two tracings (Figs. 12, 13) indicate the con- tinuous condition of spontaneous muscular un- steadiness of the finger of a nervous child ; and the continuous involuntary movement appears analogous to that indicated by the tracing of the movements of some plants. Now, if this analogy between unstable mobile vegetable cells, and un- stable nerve-ceUs, be legitimate, it should guide us to further useful observations. To be brief, Darwin's observations show that movement produced by the growth of vegetable cells is constant in the leaves, stems, and roots of many young plants.f If the movement of nervous • British Medical Joamal, December 6, 1879 ; see also " Brain," 1881, paite xi., xii., xiv. t Bee the account given of circumnntation in plants, chap. ii. 112 PHYSICAL EXPRESSION. children be pi-odiiced by a condition of brain-cell? analogous to that of the growing parts of plants or the cells of the pulvinus, it should be liable at times, under certain circumstances, to great exacer- bations. Thus guided, I have taken tracings of the finger-movements of nervous children and of those sufifering from chorea. Samples are presented here, and seem to indicate the following results : — 1. The movements of chorea are far more fre- Figs, 12. 13. — Tracing of involuntary movements of the finger m a nervous child. quent and continuous than might be expected from mere inspection of the hands. 2. These movements may be but an exaggeration of the movements of a nervous child, usually pre- sent, but often overlooked, tracings of which are given in Figs. 12 and 13. 3. The twitching movements of chorea may be compound, each visible twitching being compounded of many of the little movements seen in the other EXPERIMENTS ON MIMOSA, 113 tracings. I have never found such compound tracings in tremors as in paralysis agitans. To prove these points with certainty, numerous tracings from many cases would have to be com- pared. As to the treatment of the class of children referred to, the following experiments are very suggestive, and tjje analogy to the case of children Fig. 14. — Finger-tracings in cborea. The twitching movements are compound. hardly appears to require verbal description. Mr. M. Voss, of Streatham, has kindly communicated to me the results of his investigations. Three years ago, some seed of the sensitive plant (Mimosa pudica) was set to grow, and at a moist heat of about 90° Fahr. it soon germinated. Before the compound foliage growth had commenced, the seedlings were potted off into different earths and sand. Those planted in a soil of two parts of decayed vegetable mould to one of sand grew more 114 PHYSICAL EXPBESSION. vigorously both in height and foliage than the others ; and, after two months' growth, they were much less sensitive than others planted in two- thirds of silver sand and only one-third of leaf- mould. One or two plants were grown entirely in silver sand. These showed extreme sensitiveness to the slightest touch ; even a breath of air, or the slightest jerk of the pot in which they grew, caused all the foliage to shut up. Those plants having no nourishment beyond the gases in the air, or sand, soon turned yellow and died. The plants in two- thirds saiid and one-third decayed vegetable mould were not so robust or strong as those grown in a greater proportion of vegetable mould. They failed to produce any flowers, and died oflf at the lower temperature to which aU the plants were exposed, whilst those planted in two-thirds vegetable mould and one-third sand, fully matured their growth, flowering in a temperature of -50° or 60° Fahr., the foliage being of that full green colour denoting the fact that the spongioles of the roots had neces- sarily been supplied with the various chemical gases in the soil (set free by a due amount of moisture) requisite for producing the continued support of the plants. Their sensitiveness had, at the end of August, almost left them; indeed, after a blow on the leaf with a twig, the foliage would fall, but almost immediately regain its horizontal position. Many other useful analogies might, I think, be made in this direction ; and the subject is one full of interest to all who look upon the conditions of health or disturbance of the system throughout the THE STUDY OF CHOREA. 115 whole organized world. Among other matters, we might consider the transmission of sensitive im- pressions from one part of the plant to another; the metamorphosis of parts of a plant according to the functions discharged ; the irritability or sensi- tiveness of plants, which is in some cases far greater than anything seen in man ; the production of acid secretions in mo^le plants; and numerous other facts easily observed in plants — facts of great interest to the physiologist and pathologist; and in this direction Mr. Darwin's researches, follow- ing those of Sachs, are a climax to investigations carried on since the time of Sprengel ; facts which Sir James Paget * would have us apply to the study of human pathology. In different cases of chorea very different groups of muscles may be affected, thus indicating the very different brain areas that may be choreic. In studying a case of chorea we try and indicate the extent of brain affected by specially indicating the choreic area. The following points then should always be looked for — as present or absent in any case described — and the order of invasion of groups of muscles or their recovery should be observed : — 1. In examining a case to prove the fact of chorea it is very convenient first to look at one or both hands, held out free and disengaged. The kind of movements of the hand and fingers have been dwelt upon and described. 2. The upper and lower extremities present the greatest mass of the choreic movements. It ia • See his Lectures, British Medical Journal, October 16, 1880. 116 PHYSICAL EXPRESSION. important to note whether the finer or coarser movements be the most affected ; the amount of involuntary movement,. and the power of voluntary act that is left. 3. Hemiplegie varieties are common ; the least mobile side may be much weakened, though not much moved. 4. The face. Varieties in this group of muscles have been discussed. 5. The soft palate may present marked move- ments of an irregular twitching kind, the levator- palati muscles working distinctly. I do not refer here to the dragging of the palate by the choreic twitchings of the tongue, but to the primary twitch- ing of the palatine muscles. In some cases the levators are distinctly seen twitching upwards. This symptom is often absent in chorea, and when seen, I have observed that it has usually passed off' early. 6. The tongue may be jerked in and out. When protruded, it may present much movement, but still be kept out a fairly long time. 7. Eyes. Upper eyelids, often strongly retracted. Eyeballs often much moved. 8. The head in the active stage is often moved much. During convalescence, and when the active movements have passed off", a lolling of the head to one side is common; i.e. inclination with rota- tion to the same side, combined with slight flexion. 9. The spinal muscles and trunk are often affected. The child often balances itself very ill, throwing the scapular and upper dorsal region too far back, NERVOUS CHILDREN. 117 and thrusting the pelvis too forward, the spine still remaining symmetrical, or being thrown into lateral curves. It has seemed to me that the awkward appearance was due to want of adapta- bility of the proper compensations in the move- ments of different muscles. 10. The respiratory muscles. These may be affected much or .little ; the alae nasi muscles may be affected also. 11. The vascular centres. The heart's action is sometimes irregular. After looking at cases of chorea we naturally consider other nervous cases characterized by nerve- muscular movements, and if we study children we find examples abundant. In 1879 I * put together my notes of fifty-eight cases of children of nervous mobile tempera- ment; and for this practical purpose a summary- has been made of the principal sjmiptoms of cases of headache in children under fifteen years of age. Though recurrent headache was the most prominent and constant symptom met with in this group of cases, it was not always the one complained of by the patient or mother. Classifying the symptoms, we find the largest number referable to the mental and cerebral condition of the child. We are told that he is excitable, melancholy, passionate, or fretful; that sleep is restless and disturbed by dreams and night-talking, by attacks of terror and screaming, or by somnambulism. Often there are vague pains in the limbs, chest, or abdomen. The * See " Brain." 118 PHYSICAL KXPEESSION. appetite is often variable, voracious or entirely lost ; there may be considerable emaciation with a good appetite, and without any accompanying signs of organic disease; often there is considerable nausea or retching with the attacks of headache. Hacking cough, without physical signs to account for it, is often met with, and usually the child is excessively fidgety. In studying this group of nervous excitable children in whom recurrent headache was a main symptom, it was first necessary to look out for certain objective signs by which they might be indentified ; and these were principally found in the condition of the nerve-muscular system, the teeth, and the urine, but chiefly in the muscular system. The nerve-muscular condition was carefully observed in this group of cases. Usually, the child was made to stand with the heels together, looking straight before him, the hands being down by his side. The general steadiness of the body, trunk, and limbs was then observed, as well as the condi- tion of the face and eyes. He was next directed to put out his tongue, and, finally, to hold out both arms straight before him, on a level with the shoulder, at the same time separating the fingers. Observations were then made as to the muscles of these parts. The state of the heart, lungs, teeth, and urine was examined, and the patient's weight was recorded. As the result of these examinations, it was observed that frequently there was marked fidgetiness, and irregular movement of the trunk and limbs ; the trunk was often swayed about — TOOTH-GRINDING. 119 frequently it was inclined backwards, apparently to preserve equilibrium, while the hands were held out in front. Twitchings of the fingers * were very commonly seen, the movements being usually of independent digits, and most commonly either lateral or flexor, less commonly extensor ; the lateral movements appeared to be the most characteristic. The totigue was, usually very unsteady, but not distinctly jerked in and out, as in chorea. Twitch- ings of the facial muscles were not very common. A certain passive condition of the hand and face will be referred to presently. In a large proportion of the cases, the teeth were found flattened on their edges, as the result of " tooth-grinding ; " the teeth mostly ground were the incisors and canines, but the special teeth flattened depended upon their arrange- ment in the jaws. The pupils were measured in some cases with a catheter-gauge, after the manner suggested by Mr. Hutchinson. No special con- clusion was arrived at ; on the average, they were not large, except in a few cases near the age of puberty. The nervous hand was found to be very common; the expression of headache in the face was fre- quently seen, or rather, I should say, a certain facial expression indicative of depression was often observed, and, when seen, appeared to give strong evidence, characterizing the child as the subject of recurrent headaches. To analyze this condition of the face, the faces of adults, the subjects of migraine, were studied. The most noticeable • See Figs. 12, 13. 120 rUYSlCAL EXPRESSION. point was the look of depression, and heaviness and fullness about the eyes, especially the under eyelid. If a paper were held so as to cover either half of the face, the expression observed still remained, proving the condition of the face bilateral ; if the forehead above the eyebrows were covered, or the face below the lower margin of the orbit, in each case the expression seemed still apparent; while, if the paper were held so as to cover that portion of the face which lies between the eyebrows and the lower margin of the orbit, it seemed impossible to recognize the peculiar fades under consideration. It appears that this expression must be due prin- cipally to the condition of the orbicularis palpe- brarum. Specially observing this muscle and the parts adjacent, there seemed to be a loss of tone in the muscle ; there was an appearance of fullness and flabbiness about the lower eyelid; the skin hung too loose, with an increase in the number of folds ; and, in place of falling against the lower eyelid neatly, as a convex surface, it fell more or less in a plane from the ciliary margin to the lower margin of the orbit, a condition that is often best seen by looking at the patient's face in profile. This condi- tion of the parts about the eye was unaccompanied by any general change in the skin of the face, such as the. flabbiness seen in emphysema, and the loose inelastic skin of senile decay; further, the facial expression is not at aU necessarily permanent, but may disappear with improving health, and it is removed if the patient can be made to laugh. It is not suggested that this muscular condition only COLOURED VISION WITH HEADACHE. 121 accompanies headache ; it appears common to other conditions of depression. Having attempted to demonstrate that we may ascertain something of the condition of the brain in these nervous children by observing these muscular movements, we may now look for signs of irritation of the cranial nerves. Evidence of disturbance of the motor division o^the fifth nerve is seen in the great frequency of tooth-grinding; the condition of the muscles supplied by the facial and hypoglossal nerves has been referred to. Irritation of the pneumogastric nerve appears to be indicated by many symptoms. The varying appetite, which is often voracious, though nutrition is deficient, while at other times it is markedly defective, the frequent epigastric pain, and the retching or vomiting with headache, appear to indicate disturbance of the gastric branches; occasional palpitation without heart-disease, and the frequent hacking cough without signs of lung or throat mischief, indicate probable irritation of the cardiac and respiratory branches. As to the disturbance of sensory nerves, it was difficult to obtain evidence, as the patients were often unable to describe their sensations with accuracy. In five cases, varying from nine to fourteen years of age, distinct dyssesthesia of vision accompanied the attacks of headache, the patient seeing colours, sparks, or other illusions during the attack of headache ; in all but one case, the mother also suifered such spectra with headache. Tooth-grinding is produced by the action of the deeply situated pterygoid muscles ; champing of the 7 122 PHYSICAL EXPRESSIOX. jaws is produced by the masseter and temporal muscles ; all these muscles are supplied by the fifth nerve, and it is to their condition that we must look for information as to the condition of the cen- tral origin of the nerve. Tooth-grinding, when it has become a habit, is indicated by the flattened condition of the tips or edges of the teeth, which may be ground down — a sign that may be particularly seen in the incisors and canines. Ground teeth are very common in nervous children, such as those who suffer from recurrent headaches, restless sleep, somnambulism, and finger-twitching. In lunatic asylums and wards for imbeciles it is very common to hear tooth -grinding on every side ; in such cases tooth-grinding is a sign of central irritation of the fifth nerve. It is well to bear in mind that the sensory branches of this nerve supply the membranes of the brain and the external parts of the head. Seeing that the slight disturbances occurring during sleep in many children causes the pterygoids to contract rhythmically, it is not surprising that grave disease should cause spasm of the other muscles supplied by the fifth nerve, as in epilepsy and hysteria. The ninth nerve is motor to the tongue, and this organ being a mass of muscular fibres running in various directions almost unsupported by bones, is very sensitive to changes in the nerve-centres. In chorea the tongue is often jerked in and out in a manner quite characteristic of the disease ; in other cases it is easily kept protruded, and its substance is seen to be in a condition of constant movement. HEADACHES IN CHILDREN. 123 Such irregular movement is also very common in nervous children ; a tremulous tongue is characteris- tic of alcoholism, and general paralysis of the insane. As to the condition o£ the mental centres, dis- turbed and restless sleep was very common ; night- terrors were frequent ; often the child would scream out that " a lot of people were coming to kill him," that he "saw thg school-board man" coming, etc. In six cases, there was the distinct history of somnambulism ; in four of these, the acts performed during sleepvhad been complicated and curious; in one case, that of a boy nine years old, such attacks were frequent at the time he came under observation, on account of his headaches ; in the remaining cases, somnambulism had occurred at an earlier period. In seeking the lines of causation of recurrent headaches in children, the cases were arranged in a tabular form according to age and sex. Ages 3-4 4-5 5-6 6-7 7-8 8-9 9 10 lO-U 11-12 12-13 13-15 Males 25 1228212 2 4 1 Females 33 02312 5 5 4 2 4 5 Totals 58 1459467 6 6 5 5 As among other groups of nervous cases, the preponderance of number is with the female sex. Heredity appeared to produce a marked predisposi- tion to this neurotic condition. There was a history of recurrent headaches in the mother in twenty- four cases, and in the father in eight, while in three cases there were examples of insanity in the family. As to treatment, the restless, excitable condition of these children, and the great want of rest in sleep. 124 PHYSICAL EXPBESSION. appeared to indicate the use of bromides and other sedatives ; and this plan of treatment was generally- adopted, tonics being occasionally used, together with small doses of chloral at night for short periods, till the habit of sleep was induced. Under treat- ment, marked improvement occurred in many cases, the child gaining one or two pounds in weight in a month or six weeks, at the same time losing the headaches, sleeping quietly at night, and again becoming fit for a child's school-life. Dr. Hughlings Jackson (Lancet, July 11th, 1875) has shown that, in cases of chorea, paroxysmal head- aches are of common occurrence. Dr. Herman col- lected the histories of seventy-six cases of chorea, and found that paroxysmal headaches occurred in fifty-three cases ; in these, the headaches were not often preceded by ocular spectra. In the group of cases described in this paper, certain active and passive conditions of the muscles, especially the small muscles, are commonly met with in conjunc- tion with disturbance of the higher nerve-centres ; this appears to afford evidence that the two con- ditions may be owing to disturbance of the same nerve-centres, possibly the same as are affected in a greater degree in chorea. A girl, thirteen years of age, came under observation, complaining of frequent headaches, with ocular spectra, restless nights, tooth-grinding, and slight muscular twitch- ings, such as have been described. She had never suffered from rheumatism, but the family were rheumatic; she had no cardiac disease. Three years previously, she had had acute general chorea FINGER-TWITCHINQ. 125 for four months ; it is submitted that probably the same nerve-centres were affected in the greater and lesser illness, but in a different degree. The varieties of finger-twitching have been referred to. They may be described as — (1) Flexor-extensor; the primary movement being that of flexion, followed by a secondary extensor movement. Thig may be seen in a variety of cases, and in particular is seen in what is called " picking the bedclothes " in the typhoid state preceding fully developed coma. (2) Extensor-flexor; the primaiy movement being that of extension, followed by a secondary flexor movement. This is common in the slighter forms of chorea and in nervous children ; such twitches usually constitute the subsultus tendinum so indica- tive of exhaustion in the course of typhoid fever. (3) Abductor-adductor twitches ; the movements consisting in lateral separations of the fingers, followed by their being drawn together again. As to " finger-twitching," the " nervous hand," and " the relaxed orbicularis oculi," the following statis- tics are from an analysis of thirty-four cases from my note-books of the East London Children's Hospital : — Finger-tmkhings in 19. — Twitchings alone . . in 8 cases. With the nervous hand „ 8 With relaxed orbicularis „ 3 19 The nermuB hand m 19 — Nervous hand alone . „ 7 With twitchings . . „ 8 With relaxed orbicularis ., 4 19 126 PHYSICAIi EXPRESSION. Orhicularus relaxed in lO.^Orbicularis relaxed alone in 3 eascB. With the nervous hand „ 4 „ With twitchings . . „ 3 „ 10 „ As to the general character of this group of thirty- four nervous cases in which nerve-muscular signs were specially noted, no cases of known organic brain disease were included, and all were under fif- teen years of age. I have abstracted and summarized the diagnosis of the nineteen cases in which the " nervous hand " was seen : — " Headaches," 6 ; " neu- rotic temperament," 3 ; " anaemia and headaches," 2 ; " headache and somnambulism," 1 ; "restless sleep," 1 ; " laryngismus," 1 ; "a dull child with congenital ptosis," 1 ; " old rickets," 1 ; " debility," 2 ; " slight chorea," 1. The cases of " finger- twitching " had the same general characters as those with the " nervous hand," therefore I do not further describe them. As to the kinds of finger-twitching, the varieties were noted as foUows ; — Simple twitching, 9 ; flexor and adductor, 5; flexor, 3; abductor-adductor, 1; extensor and abductor-adductor, 1. As shown in the tables above, the "nervous hand " was associated with " finger-twitches " in eight cases. In cases where the right and left hands were com- pared, we find a difference in six cases, always to the disadvantage of the left hand ; it specially presented "the nervous position" in four cases, and finger- twitches were specially marked on the left side in two cases. The cases with "relaxed orbicularis" were specially marked by recurrent headaches, some with optical illusions and scarlet zigzag forms. ATHETOSIS. 127 In two cases herpes zoster occurred while under observation. Athetosis is a condition of brain disease charac- terized during the life of the patient by movements, more or less constant, in the muscles of the extremi- ties. Athetosis usually affects one side of the body only, but may affect both sides. The movements are much slower than those .of chorea, and are not usually a series of gesticulations, but differ in their combinations from the movements performed in health. The plate gives the common postures seen in their different cases j they are postures that would not be assumed under the guidance of a normal brain influenced by emotions. To give some idea of the expression of this con- dition of brain disease, I quote the account of the movements seen in three cases which I published.* Case I. — Athetosis with Epilepsy. The girl was of fair stature, rather pale and thii, and of weak intellectual power. She could walk, assist her mother iii the house, and answer ques- tions, but was very dull and apathetic. - ' When seen the following descriptibn was taken ; — The left upper extremity is almost useless for most voluntary purposes on account of the condition of the hand. If told to put her hand to her mouth, or to the back of her head, the hand gets there, being moved slowly and awkwardly by the action of the muscles moving the shoulder and Jelbow; but though flexion and extension of the elbow be suffi- • " Brtiin," part xiii. 128 PHYSICAL EXPRESSION. ciently volun- tary to perform such acts, invo- luntary move- ments of prona- tion occur, while the hand is being moved up to the mouth. All through the time of the general movementofthis limb it is obvious that there is much perfectly involuntary movement of the wrist, often causing marked flexion, or affect- ing independent digits. As to the con- dition of the hand, the de- scription was taken while the forearm was gently supported by the mother, the wrist being left perfectly CASKS OF ATHETOSIS. 129 free. It was then noted : The wrist droops, the meta- caq)us hanging straight down, but frequently supi- nated rather quickly, but not in a jerky manner ; the hand then passes slowly back to its former position, the series of movements being repeated. Flexion and extension of the wrist through a few degrees are nearly constant movements. The movements of the fingers are almost inces- sant, the primary and quickest movements being flexor, followed by slower extension. The move- ments are slower than the jerks of chorea, and more deliberate, not looking like gesticulations; they are purposeless and gliding in kind. The fingers are constantly going through gro- tesque movements, sometimes crossing one another, sometimes one is extended, while the others are flexed ; there are no adductor and abductor twitches, such as are usually seen in chorea; the thumb is mostly turned in on the palm, but is also often extended. These finger movements appear utterly purposeless, looking as if the tendons were merely pulling upon dead fingers, as an automaton pulled by strings, or like the movements of a boneless limb, such as an elephant's trunk or an anemone's tentacle. The metacarpal bones are rather con- tracted together by the arching of the palm of the hand, giving it a narrow appearance. Case II. — Athetosis associated with Chronic Hydrocephalus. His general health was good, and no disease was detected in any organ but the brain. The condition Case 1 Fig. 16. — Cases of Athetosis showing Hand Postures. BILATEEAL ATHETOSIS. 131 of the right upper extremity especially attracted attention. The following description is compiled from notes taken on various occasions : — The limb was useless for any purposive move- ments; there was no voluntary power over the hand, and but little over the shoulder and elbow. When a flower was held up to the child, he looked at it and made a noise, evidently indicating his pleasure, then moved his left hand to the flower, took hold of it, and tried to put it to his mouth. He could not take the flower with his right hand The wrist was frequently kept half flexed, while the fingers were extended and flexed generally altogether, in a slow and rhythmical manner. Pro- nation and supination were not common ; the move- ments of the wrist were usually confined to flexion and extension of the fingers as described. The hand was moved when pricked. There was no difierence between the similar measurements in the two arms, but there was some rigidity of the right arm. The right leg was weak, but presented no athetosis. Here the condition of the limb was associated with brain disease and convulsions. The move- ments occurred in a paralyzed arm, and were more limited in extent than in Case I. Case III. — Double Athetotis not associated with Epilepsy. Eliza R., aged four and a half years. She was a playful, intelligent, pleasing little girl, good and well-behaved, and soon became a general favourite. 132 PHYSICAL EXPEESSIOX. Her general health was good, and development appeared good in all particulars, but for the athe- tosis ; she was well nourished. The child was unable to stand or do anything for herself on account of the movements of the hands and feet, associated with which there was, no doubt, some want of muscular power. The muscular con- dition of the head and face appeared natural There appeared to be a fair amount of voluntary power over the shoulders and elbows, so that she could hold a doll to her. When told to take hold of a toy she brings her hand to it, but is unable to open the fingers so as to clasp it ; all through the time of this eflfort the fingers are in constant movement. When the object is placed in her hand she clutches it and is unable to drop it. Supporting the left upper extremity free from the trunk by holding the humerus, it was possible to observe the following movements succeeding in a rhythmical manner. The wrist was frequently bent backwards, and sometimes abducted. The thumb is mostly bent in on the palm, turned in under the index finger. The fingers are frequently extended at the meta- carpo-phalangeal joints, remaining flexed at the inter-phalangeal joints. The greatest power of extension seems to be of the index finger. In getting the hand near an object it moves about much before it comes in contact with the object, and then cannot grasp it on account of the condition of the fingers. The fingers are usually kept flexed ; she cannot spread them voluntarily. When the DEFECTIVE DEVELOPMENT. 133 child is played with, her fingers spread open spon- taneously, as also when attention is specially drawn to the other hand. When one's finger is slipped into her hand, her fingers grasp it, and cannot let it go unless the fingers happen to open of themselves. When she makes an effort and puts her legs out of bed to show her feet, the involuntary movements of the hands apd fingers are increased, and move- ments of pronation and supination are noticeable. The toes of both feet are continually being flexed and extended, but these movements are less in degree, and less characteristic in kind than those of the hands. She can kick her legs about in bed, but cannot walk. The eyes and special senses are normal, and general sensation is good. Heart and lungs healthy. The movements are very strange and purposeless ; in kind they have more resemblance to voluntary movements than is usual in athetosis, and less of the gliding, successive-rhythmical character. During sleep the hands are usually quiet. This condition of the child appeared to have existed from birth. There were no signs of pro- gressive disease. The family were quite healthy. Defective Developmental Conditions as seen PEINCIPALLT IN ChILDKEN.* In seeking for explanation of the circumstances attendant upon and causing some of the special * From Medical Timet and Gazette, January 21, January 28, and February 11, 1882. 134 PHYSICAL EXPRESSION. developmental conditions commonly found in children, it seems necessary, first, to arrange and examine cases of gross and obvious deformities, where the kind of ill-developments, and any co- existing defects and consequent deviations from normal function, may be easily observed and re- corded. JFor this purpose I have abstracted from my case- books the notes of twenty- three cases, imbeciles and idiots being generally passed over. These are arranged as follows : — Group I. Case 1. — Heart-defect — Fingers clubbed — Cya- nosis — Palate cleft. Case 2. — Heart-defect — No cyanosis — Deformity of hands — Epilepsy in family. Case 3. — Mitral and tricuspid disease — No cya- nosis — Malformation of hands. Case 4. — Heart-defect — Congenital cyanosis — Left hemiplegia, dependent upon defect of right hemisphere — Bell's paralysis on right side of face, with deformity of right ear. Case 5. — Heart-defect without cardiac symptoms — No cyanosis — One ear deformed. Case 6. — Congenital heart-defect, with a varying bruit — No cyanosis — Patency of inter-auricular septum — Want of power in legs from birth, with some rigidity of left. JRemarks on Group /.—This series of six cases illustrates the concurrence of congenital defect of the heart with other deformities, e.g. cleft-palate, defects of hands, ill-formed ears, congenital defect DEFECTIVE DEVELOPMENT OF THE HEART. 135 of brain. Of this latter many examples might be added, and I propose at another time to give more examples of concurrent defects of heart and nerve- centres. In some of these patients the heart was specially examined, not on account of any signs of heart-defect, but in the search for examples of con- current congenital defects. (Edema was absent in all these cases. . Cyanosis was present in Cases 1 and 4, and absent in the other four cases of this group. Group II. CASES WITH EVIDENCE OF CONGENITAL HEART- DEFECT, NOT ASSOCIATED WITH OTHER KNOWN DEFORMITIES. Case 7. — Heart-defect — Cardiac hypertrophy — No bruit — Marked cyanosis — Convulsions — No other defects. Case 8. — Heart-defect— No cyanosis — Bruit in pulmonary area — No other defects. Cased. — Heart-defect — Cyanosis— Bulbous fingers — No other deformities. Case 10. — Heart-defect — Cyanosis — No clubbing of fingers or toes — No other deformity. Case 11. — Heart-defect — ^Varying amount of cya- nosis — No bruit^— No other deformities. Bemarks on Groups I. and II. — Of these eleven cases of heart-defect no co-existing deformity was found in five. Cyanosis was present in six cases out of the eleven ; and it is noteworthy that of these cyanotic cases the larger proportion were in Group II., where no co-existing deformities were 136 PHYSICAL EXPRESSION. found. In Case 10 cyanosis was more marked in the feet than in the hands. As to the signs of the presence of heart-disease, bruits were present in nine cases ; hypertrophy, evidenced by forcible impulse, distinct area of dulness, strong pulse, or proven by autopsy, was present in seven cases ; irregularity of action was present in three children. Clubbing of the fingers in three cases was noticed. No symp- toms dependent upon the heart-defect were noted in six of the cases given. In six cases some kind of evidence was obtainable as to causation. I found no evidence of "maternal impression" as a cause of congenital defects of the heart ; but there was evidence against the family in four cases in such particulars as to many deaths or several mis- carriages preceding the birth of the patient. In two cases there was no bruit, and in another case the presence of a bruit was very doubtful Group III. CASES OF CLEFT-PALATE. Case 12. — Cleft-palate — No heart-defect — Head small. Case 13. — Cleft-palate — No heart-defect — Head small — Premature birth — Marasmus. Remarks on Group III. — Neither of these cases presented any known coexisting deformity, but in Case 1 a heart-defect accompanied cleft-palate. Such a coincidence appears not improbable, and is worth looking for in other cleft-palate patients as a question affecting prognosis and the safety of chloroform in operating, etc MISCELLAKEOUS CASES. 137 Group IV. DEFORMED UPPER EXTREMITY, AND INTRA-UTERINE AMPUTATIONS. Case 14. — Fingers webbed — Ears not symmetrical ■ — Excessive epicanthic fold * — Cerebral deficiency. Case 15. — Deformed hand — Intra-uterine ampu- tation (?) — Nq other defect. Case 16. — Deformed arm — Intra-uterine ampu- tation (?) — No other defect. BemarJcs on Oroup IV. — Two of these cases pre- senting defective upper extremities looked as if they had been intra-uterine amputations, and being traumatic, and accidental rather than de- velopmental, it is not surprising that no other defect coexisted. In Case 14 we see coexisting defects. The asymmetry of the ears and the webbed fingers were surely developmental defects, and they were accompanied by defective develop- ment of hands. Group V. MISCELLANEOUS CASES. Case 17. — Double coloboma of iris — No other defect. Case 18. — Congenital smallness of one eye — No other defect. Case 19. — Deformity of right ear and temporal bone — No other defect — Rickets. ♦The term "epicanthic "fold is applied to the portion of skin that lies at the inner angle of the opening of the eyes towards the nose. This is occasionally developed as a kind of web, called the epicanthic fold. 138 PHYSICAL EXPRESSION. Case 20. — Congenital jaundice — Double hydrocele. Case 21. — Ichthyosis — No other deformity. Case 22. — Ichthyosis, moderate in degi'ee — No other defect. Case 23. — Ichthyosis — Deformity of both ears — Heart healthy. Of the twenty-three cases, thirteen were males and ten females. Looking at these cases from the point of view indicated, the following points seem worthy of consideration : — The coexistence of deformities was not uncommon. This is seen in all the cases in Group I., also in Cases 14 and 20; while in Nos. 12 and 13 the head was also below the average size. The family history is noteworthy as giving indications of possible causation. In Cases 2, 6, 10, and 14, a feeble constitution in the family is indicated by miscarriages, many deaths, insanity with epilepsy in previous members of the families before the birth of the patients described. It also appears in some histories that the tendency to ill-development exhausted itself, the later members of the family appearing healthy. The secondary effects of the congenital defect are im- portant. Defect of heart may lead to cyanosis, clubbed fingers, and perhaps low temperature; it is also said to lead to a low mental development. If the internal ears are faulty, dumbness may follow ; obstruction of the common bile-duct must secon- darily cause jaundice. Ichthyosis being attended with inaction of the skin, secondary bronchitis is common. Cleft-palate may lead to atrophy from inanition, and a head below size may lead to DEFECTS IN DEVELOPMENT. 139 general organic feebleness ; but the former condition may be rectified, and not lead to atrophy ; in a former paper (Bntish Medical Journal, October 30, 1880) I showed that small-headed children may, under proper care, develop a fairly sized brain. Here the developmental defect is, to some extent, removed. Of the eleven cases of heart-defect only one appears tp have had convulsions — a symptom constantly inquired for. This case (No. 7) was cyanotic ; there were, however, six cases of cyanosis without any history of convulsions. It will probably be admitted that in the structure and general anatomy of the human body "the normal " is but the average as it is found ; and so difficult is it in all the organized world to define and distinguish accurately between " the variation and the monster," either in the seedling plant which is different from its ancestors, or in the " genius " in the human species, that we must look carefully before we say that any specimen is monstrous or diseased ; but in the gross cases above narrated the abnormality is obvious. Possibly, in these co- existing defects of development we may see some explanation of the accompaniment of vulgar faces and low minds, i.e. low development of the brain ; when such samples are seen in a family it may be well to look for the lines of causation in the de- scending scale of the development of the family. Among common defects may be enumerated de- fective or excessive ossification of the skull, excess of the epicanthic fold, defects of the eyeball, webbing of fingers and toes, naevus, etc. 140 PHYSICAL EXPRESSION. CHAPTER Vm. POSTURES CONSIDERED AS MEANS OF EXPRESSION. Definition of a posture — Simplicity of study — Historical records of postures — Postures of all parts — ^A change of posture is move- ment — A posture is due to resultant action of muscles and their nerve-centres — It is a direct mode of expression — Free or disengaged parts most expressive — A limh labouring is not sus-eptible to mental expression — Organic postures, as from difficult breathing— Postures due to gravity — Effect of gravity on plants — Gravity acts differently during sleep — It can affect the postures of the face — Postures due to reflex action — Spontaneous postures — Fallacies — Classification and aniilysis of postures — Coincident postures — Symmetry — ^Pos- tures in a:'t — Postures in animals — Postuies in plants — Summary. The term "posture" indicates the relative position of the several members of the body with regard to one another and the body in general, or the relative position of the individual parts of a member. The^ study of postures as means of expression is, in some respects, simpler than the study of move- ments, as means of expression; for a posture is a condition of quiescence, and, as such, is more easily observed, described, and analyzed. Further postures can be represented by verbal description, by casts, photographs, or drawings; they have been repre- sented in works of art from ancient times, in MECHANISM OF POSTURES. 141 statues and in drawings, in wall decorations, and on pottery, so that the history of expression by postures can be studied with considerable complete- ness and precision. The posture of a limb depends upon the relative position of the bones of the limb ; and this depends in its immediate mechanism upon the result and action of the opposing muscles which move the limb.^the relative tone of the antagonistic flexors and extensors, the adductors and abductors, the pronators and supinators, etc. The posture of the limb is the result of the balance of the opposing muscles. It may be said, then, that a posture is the j resultant action of the balance of the opposing muscles which move a part of the body. Taking this meaning of the term posture, we may speak of postures of other parts of the body besides the limbs. The eyes are members moved by opposing muscles ; we may, then, speak of their relative posi- tion to one another, and the position of each with regard to the axis of the orbit, as the postures of the eyes. In the face the different parts are called features. The cheeks, the openings of the eyes, nose, and mouth, are features of the face. The features of the face are moved by opposing muscles, so that it is convenient to speak of the postures of the face, or facial postures, as the result of the action or tone of the facial muscles. We n^y also speak of postures of the head and trunk. A change of posture is the effect of movement ; the posture is the result of the last movement ; the cause of the last movement is therefore the cause of the posture. We may describe in anatomical terms 142 PHYSICAL EXPRESSION. the open extended hand and the closed hand ; to say that the hand changes from one posture to the other is one method of describing the movement that has occurred. If movements are expressive, postures must be expressive for the same reasons. Postures, like movements, may be taken as in- dices of the action, and of the condition of the central nerve-system, because they are the result of the action of the central nerve-system upon the muscles. The posture of the hand, or other part, is the result of the balance of the muscles of the part. The position of the bones of the limb is the re- sultant of the action of the muscles, and is regu- lated, to a large extent, by the nerve-system. To consider one part only, let us take the hand and forearm. I have hitherto spoken as though only one stimulus could come from the nerve-centres to the muscles of the limb at the same time; it is probable that many nerve -centres, or portions of the central mechanism, are together sending stimu- lating currents to the muscles, and that the balance of muscular action is the result of the balance of the action of many nerve-centres. It is, however, not necessary for our purpose to enter upon this dis- cussion as to whether one or many nerve-centres cause a posture ; we can proceed, neglecting this point and making the admissions that the balance of the muscular action which regulates the posture of a limb is the outcome of some portion of the central nerve-mechanism. A posture, when thus produced, is a direct expression of the action of some part of the nerve-mechanism. CHANGE OF POSTURES. 143 We will suppose that the right arm, as in Diana (see Fig. 34), is holding a spear firmly; a strong nerve-current is being sent to the muscles of the right forearm, causing the hand to grasp the spear. In order that this position of the hand may change, the stimuli coming to the muscles of the limb must change ; they may be all reduced in strength, or their relative strength may be altered. If the woman is startled, she may drop her spear; if she meet a friend, she may purposely throw it away, and then the hand is free to be acted upon again by its nerve-mechanism, the action in the hand produced by the central organ being thus directly expressed. It is iir a free and disengaged limb or part that we best see direct expression. The hand of an ener- getic speaker, if it is not engaged in leaning on the table, or holding a paper, etc., will often express by its movements the general mental state of the speaker. The limb is moved by the strongest motor stimuli that come to its muscles. We see, then, that in the case supposed, the strongest motor impulses coming to the muscles of the limb when it is disengaged, are in some way connected with the mental condition of the subject. If, on commencing to speak, the man hold his hat in his left hand, it is probable that he will continue to hold it throughout his speech. The motor currents to the left side are continuing uninterruptedly, but it may be that (as it is said) his emotion may be so strong, that the current produced by emotion proceeding to his arm will be stronger than the original current ; then he will drop his hat and gesticulate with his arm. It 144< PHYSICAL EXPRESSION. is, then, in free and disengaged limbs and parts that we see the best examples of direct expression of mental conditions. Examples of free and disen- gaged parts may now be compared with examples of the engaged stimulated condition of the same parts. The hand of a labourer is seen engaged in digging with his spade ; his nerve-muscular energy- is expended in holding and driving his spade. It would, under such circumstances, require a very strong nerve-current sent to those muscles to alter this forcible stimulus. Hence, the hand engaged in digging is not very impressionable and expressive of the finer motor actions of the nerve-mechanism. When the man puts aside his spade, and talks, especially if at rest, his hand gesticulates and ex- presses his emotions. The head is a part or member of the body usually disengaged, and easily moved by slight stimuli; hence movements and postures of the head are usually highly expressive. The head may, how- ever, be not free to move under a slight stimulus, as when a costermonger or fisher-womau carries a basket on the head. The eyes move freely in their orbits, and their movements give much expression. The eyes may, however, be strongly attracted to an object, as a light (this is probably a reflex action). When the eyes are thus fixed, they are not easily moved by slight stimuli, and cannot be said to be free and disengaged. The face, again, is a region in which the muscles ( 145 ) I 146 PHYSICAL EXPRESSION. are usually free to be stimulated to contraction by slight causes. The capacity of the face for expres- sion exceeds that of any other part of the body. The mobility of the face varies greatly, and there are circumstances under which the facial muscles are not free for the expressions of emotion, as when eating, and when a strong light causes spasmodic contraction of the orbicular muscles of the eyes. Postures of the body may be due to organic con- ditions ; they may be due to conditions of the organs, and not express the simple action of the nerve-mechanism. Thus, in spasmodic asthma, the patient, if lying in bed at the commencement of the seizure, is obliged at once to rise up, and he sits leaning forward, with his knees drawn up, his elbows on his knees, and his head supported by his hands, labouring for his breath. Various postures are assumed to facilitate respiration ; the patient stands erect, with his head thrown backwards, seizing some object to give greater vigour to his efforts, or he leans the head forward on his hands. Such postures are assumed to enable the respiratory muscles to act with greater mechanical advantage. In heart-disease the patient is often unable to lie down, and sits in bed, or in his chair, supported by pillows. Sir Charles Bell * draws attention to pos- tures resulting from organic conditions in his criticism upon the Dying Gladiator (see p. 303). Gravity is often a factor of great potency in producing postures of the body. All living bodies are under the influence of the same laws of gravity * Op. eit., p. 194. EFFECT OF GRAVITY OK POSTURES. 147 as non-living things. The general effects of gravity as affecting the growth and development of animals have been referred to by many authors, but the effect of gravity as a stimulus upon growing or mobile parts in animals has been but little investigated. In plants gravity influences growth in such a manner as to produce various movements.* Gravity may .be a factor in causing postures in the human body in two different ways. Gravity produces a tendency in a limb to fall downwards, i.e. to place itself with its centre of gravity as low as possible. Thus, when the muscles of a man's arms are not stimulated to action by nerve-currents, and still the man stands erect, the aims, under the influence of gravity, fall by his sides. When in a strong man the head bends to one side, it tends to become erect again ; that is, the muscles tend to resume such a balance that they are in equal tension on the two sides. This may receive some explanation on the supposition that when gravity causes the muscles on the convex side to be strained, a nerve-stimulus is received by those muscles through reflex action causing them to contract. It must, however, be borne in mind that the facts concerning growth of seedling plants show that living cells ma3' be directly stimulated to certain kinds of action by gravity. The face is affected by the action of gravity when paralyzed or passive. The jaw drops when the masticatory muscles are relaxed, and when the facial muscles are paralyzed, the tissues of the face * Prantl and Vinos. " Text-book of Botany," p. 87. 148 PHYSICAL EXPEESSION. fall in their relative position to the skull -which supports them. This is easily observed in cases of palsy of one side of the face, where the position of the features on the two sides is easily compared.* Postures of the face may then in part be due to gravity. As far as I know, the positions of the eyes are not affected by gravity. One of the indications or expressions of a moderate conditions of sleepiness or debility is that the head is not kept erect ; gravity fails to stimulate the muscles put on a slight strain by bending (inclining) the head to one side. In looking to the significance, meaning, or direct expression of postures, we must try and determine the causation. Some postures are the result of reflex action. If a small object is placed in the hand of a healthy child, a year old, the fingers close on it. This is probably a purely reflex movement. The posture of the hand or flngers which results, beinor due to reflex action, may be termed a reflex posture, in contradistinction to the so-called spontaneous postures. Examples of reflex postures are seen in contraction of the orbicularis oculi under the influence of light ; in many cases where an object is grasped in the hand without a conscious act on the part of the subject ; in the arm when kept near a part of the trunk that is the seat of some irrita- tion (being tickled). Spontaneous postures are those which appear to come about as the result of the intrinsic action of • See chap. xi. SPONTANEOUS POSTURES. liH the nerve-centres, and which we cannot at present classify a.s either reflex or voluntary. The postures assumed in an infant, who probably at birth has no volition, are spontaneous if they are not reflex. Postures in the adult are termed spontaneous if they are not known to be either reflex or voluntary, i.e. accompanied by consciousness. Postures assumed by the subject jyhen unconscious, as from the in- fluence of chloroform, may be said to be spontaneous, the outcome of the action of the nerve- mechanism. The postures that we see assumed under various emotions, when we have evidence that they are not purposely assumed, are indications of the action of the nerve-centres ; hence the value of the study of postures in children, whose movements are often so little the result of self-consciousness, and are so commonly purely spontaneous. In certain other cases postures are not indications of the condition of the nerve-system. Postures of the hand are often due to chronic changes in the joints, the ends of the" bones which are in apposi- tion becoming changed as the result of disease, and the ligaments so thickened and contracted as to interfere greatly with the action of the muscles upon them. If the muscles cannot freely move the joints, the stimulus from the nerve-centres cannot be accurately expressed by the postures of the limb. In many cases of crippling rheumatism the postures are caused by the local joint condi- tion and indicate the state of the joints, not the condition of the nerve-centres. So also diseased conditions of the muscles may prevent expression by nerve-muscular signs. 130 PHYSICAL EXPEESSION. Another set of cases must be mentioned. The postures observed may be the result of a defect of the nerve of the limb, or of the part of the cord or brain with which those nerves are con- nected. In such cases the postures assumed are expressions of the chronic diseased condition of the nerves or their central origin, and mobile expressions are not indicated. / Voluntary postures imply voluntary movements. We all have some idea of the difierence between voluntary and spontaneous movements. It may be said that a voluntary movement is an act of volition, and is preceded by a condition of consciousness. We need not discuss the question here; it will be referred to again in the chapter on " Physical Signs of Mind." We all know that postures can be volun- tarily assumed by an exercise of the will. Voluntary postures are objective signs indicating an effect of the will. It is not proposed that we stop to inquire here what the will is — whether it be a function of the brain or otherwise; we are here only concerned with its expression in objective nerve-muscular signs, the motor manifestation of the physical basis of the will. Grasping a spear, holding the hand of a friend, are nerve-muscular physical signs, and doubtless they express feelings and vplition in the subject. We are here concerned to describe and analyze the outward signs of expression — the posture of the hand holding the spear, or grasping the hand of the friend. It appears, then, to be impossible to define exactly what a voluntary posture is; we COINCIDENT POSTUEES. 161 cannot give definite criteria by which we may distinguish a voluntary posture from one that is reflex, or the spontaneous outcome of the action of the nerve-centres. We fail, then, to define the adjective "voluntary" as applied to a movement, and this failure is due to our want of knowledge of the criteria of volition.. So we shall fail again and again wh^ji we try to determine logically the physical criteria of mind. We may accept certain criteria as evidence of mind; we cannot prove those signs to be evidence of mind. Something ought to be said now about the classification and analysis of postures. Now, as postures are nothing but the results of movement, the principles which enable us to analyze and classify movements ought to enable us to analyze and classify postures. It appears needless to repeat those principles verbally, but they may be shown to be applicable to analysis of postures by means of the table in chap, ix., p. 172. Coincident postures are often seen in practice, thus: when the left eye is directed outwards, the right eye is directed inwards, and vice versa. Sym- metry of posture is a division of coincident postures. Certain postures of the head and the hand so com- monly coincide as to give special expression. In a weakly child we often see the left hand in the nervous posture, and the head in slight right rotation with right inclination and flexion. In that physical condition where the mental state is called " horror " at the sight of an object, the upper extremities extend towards the object, the eyes and head 152 PHYSICAL EXPRESSION. rotate from it.* To speak of the coincidence of two or more postures is to speak of a member in the series of postures. We speak of coincidences of pos- ture just as we speak of coincidences of movement. The study of hemiplegia and hemispasm, in comparison with examples of coincident postures, and movements which are highly expressive, sug- gested to me to look for facts concerning coincident postures such as are recorded above. y In art, movement is expressed by the postures of the subject. The outstretched hand expresses energy in movement, for the limb could not so remain unless force were expended. Emotion is often expressed by posture. The head is hung in shame, extended in adoration, rotated with flexion and inclination in nervousness. Darwin, in his work on " Expression," has shown that probably the snarl of the dog is expressive of similar emotion to the sneer of a man, and he produces many examples of analogy between ex- pression by postures in animals and in man. Lastly, plants, in their parts which move, have expressive postures. The Mimosa leaf expresses recent excitation ; the infolded tentacles of the leaf of Drosera expresses that an insect or piece of nitrogenous food has been caught by it. Swmmary. — To summarize what has been said in this chapter ; postures are the results of movements, and for that reason they have the same physio- logical significance as movements ; that is, postures * Compare this with what was said ahont head movements in hemiplegia (see chap. vii.). SUMMARY, 153 are nerve-muscular signs. A posture is the position of a part of the body or a member, and is due in its mechanism to the balance of its muscles. We may, then, speak of the postures of any members of the body, head, face, eyes, etc. It is in free or disengaged members, or parts, that we see the best examples of direct expression. A hand engaged in labour is less expressive of mental conditions than an unoccupied hand. Postures may be determined by organic conditions rather than by the state of the nerve-centres ; thus, the body is supported, when there is urgent difficulty of, breathing. In the Dying Gladiator the body is supported by the arm to assist the breathing. Gravity often determines the position of the head and limbs, when there is no strong nerve-current proceeding to its muscles. The position of a member may be due to reflex action. Observation shows that a special posture follows uniformly upon the stimulation of a par- ticular sensory surface ; here the posture is not the spontaneous outcome of what originates in the subject, and the posture is less likely to indicate the volition or the brain condition. Free and disengaged parts are alone expressive of brain conditions. Postures may be due to organic disease, or to changes in the joints ; in such cases they are not direct indices of the brain. The effects of gravity are worthy of study ; they are better understood in plant-life than in man. Postures may be classified in the same manner as movements. We see examples of postures alike in man, animals, and in plants ; in each case such signs are expressive. 154 PHYSICAL EXPEESSIOK. CHAPTER IX POSTURES OF THE UPPER EXTREMITY. Method of examination — Anatomy — The convulsive hand con- trasted with the iiand in fright — The feeble hand and the hand in rest — The straight extended hand, normal — Applica- tion of the principles of analysis — Straight extended hand with the thumb drooped — The nervous hand, seen in art- Energetic hand the antithesis of the nervous hand — Table giving analysis of postures, and application of the principles — Principles of analysis— Anatomical analysis — Small parts contrasted witli large parts — Interdifferentiation— Collateral diflferentiation — Symmetry — Excitation of weak centres — General excitement or weakness — Analogy — Antithesis — Fallacies — Methods of determining whether a posture is the outcome of the spontaneous action of the nerve-centres. I PSOBQSE here to speak of postures of the arm, forearm, and hand. The postures that have been frequently observed in actual life will be described, and their significance wiU be discussed affcerwardSi I have made observations upon these points in some thousands of subjects — in healthy subjects, and among my patients, males, females, and chil- dren. I have, as the result of these observations, been led to accept certain postures of the upper extremity as expressions of certain conditions of the individual, as physical signs, or objective ob- ANATOMY OF THE UPPER EXTKEMITY. 155 servable expressions of the conditions inherent at the time. In making such examinations while the subject is standing, he is requested to hold out his hands, or sometimes to hold out the hands with the palms downwards. This affords the opportunity of ob- serving the free or disengaged hands. The pos- tures, the synjmetry, presence of any movements, the coincident balance of the head or spine, etc., can be noticed while observing specially the hands. The upper extremity in man consists of the fol- lowing parts : — The upper arm, with the humerus as its bone, which is articulated at the shoulder with the scapula or blade-bone. The lower end of the humerus articulates with the radius and ulna, the bones of the forearm. The forearm articulates with the wrist, which is made up of eight small bones, collectively spoken of as the carpus. The palm of the hand consists of five metacarpal bones, each of which carries its own digit. These bones, termed collectively the metacarpus, are capable of slight movement, enabling them to be approximated like a bundle of sticks tied together, or spread out. The junction of a metacarpal bone with its digit is called the metacarpo-phalangeal joint, or the knuckle. The individual bones of the fingers and thumb are termed " internodes." For the general convenience of description, I have illustrated and tabulated eight typical postures indicative of positions commonly seen. Perhaps one of the best known spontaneous 156 PHYSICAL EXPRESSION. postures of the hand due to the brain condition, is the " convulsive hand." , This was well described by Trousseau * as a common condition of the hand in tetany. "In the upper limbs, the thumb is forcibly and vio- lently adducted ; the fingers are pressed closely together, and semiflexed over the thumb in con- sequence of the flexion of the metacarpo-phalangeal articulation ; and the palm of the hand being made Fig. 18. — The Convulsive Hand. hollow by the approximation of its outer and inner margins, the hand assumes a conical shape.'' The condition of the metacarpus is specially noteworthy. I have taken casts of several cases and have measured many more. It is, as Trousseau described it, arched or contracted by approxima- tion of the metacarpal bones, which are screwed together. Important variations of this posture might be described; it is often seen in various pathological states. * " Clinical Medicine," vol. i., New Sydenham Society's transla- tion, 1867, p. 375. ANALYSIS OF THE CONVULSIVE HAND. 157 Let US now analyze this posture due to tetany, and observe and describe the characteristic con- stituents of the posture, and see if these elements occur in other less-marked cases. The small parts, the digits, and the larger parts are all in flexion; there is a general struggle among the muscles, and the stronger move the bones ; the nerve-centres appear to be aU in activity, and the Fig. 19.— The Hand in Fright. stronger prevail in causing the general flexion. This posture is antithetical to the hand in fright. Hand in fright. Hand in convulsions. ■Wrist Extended Flexed Metacarpo-phalangeala . . Straight extended „ First and second ittemodes „ „ „ Thumb, metacarpo-phalan- geal ,. ), „ „ internode ... „ „ „ Phalanges, relative position All in same plane Contracted and adducted. 158 PHYSICAL EXPRESSION. The general strength of the nerve-discharge is indicated by all the strong centres being stimulated, whereas in the antithetical posture the weak extensor centres are stimulated.* Let me say here, that in using the terms " con- vulsive hand," " hand in fright," etc., I do so only as convenient terms, and do not wish to make the tacit assumption that the hands are always in this Fig. 20.— The FecblD Hand. posture in the condition of convulsion or in the emotion " fear." Now to discuss the posture of the "hand in fright" (Fig, 19). The anatomy of the posture has been described. The small parts, the phalanges, as well as the large joint, the wrist, are alike extended; the joints further from the trunk, as well as those * The contracting or drawing together of the metacarpal bones is- an element in this posture, seen also in the " feeble hand." HAND IN EEST. 159 nearer, are in the same state ; the collateral parts, the fingers and metacarpals, are all in similar rela- tion ; there is no collateral differentiation. The feeble hand. — If the disengaged hand of a feeble child or woman is held out, we commonly see a slight, but important, departure from the hand in rest. The thumb is drooped, and its meta- carpal bone is •approximated to the palm, all the metacarpals being bent round as in the convulsive hand. This is a posture often seen. Tlie hand in rest may be seen in a strong and Fig. 21.— The Hand in Keet. healthy subject during sleep, also when the hand hangs free and quiet, as when doing nothing, and in a state of mental quiescence. I have often seen it during quiet conversation, and in men while walking or travelling. The metacarpus is often slightly contracted, but not to such a marked degree as in the " feeble hand." The " feeble hand " and the " hand in rest " have the same anatomical description, but they differ in degree. It was the result of clinical observation that induced me to describe the two forms. The 160 PHYSICAL EXPRESSION. hand in rest is normal in the condition of resting ; the feeble hand is hardly to be considered as normal, at any rate in a man. The principal difference in the two postures is in the metacarpus; in the feeble hand the contraction of the metacarpus is marked, and this I believe to be abnormal, because I do not see it in a strong subject, and because it is often seen in convulsion and in chronic rigidity sequent to paralysis, etc. The normal straight hand when held out is the posture typical of strength; This is the posture in which a strong and healthy maHj woman, or child Fig. 22.— The Straight Hand. holds out the hand to request; there is no flexion, no extension, but perfect balance. This statement is founded on numerous observations. I have often requested a body of students, or other healthy sub- jects, to hold out their hands; so also healthy children, who could know nothing of my object ; and thus I have had the opportunity of judging that this well- balanced posture indicates the normal action of the nerve-mechanism employed in the act. There is no interdiffierentiation, no collateral differentiation, no difference of small parts in con- trast with large parts ; the metacarpus is straight transversely, in contrast with the contracted meta- carpus of the feeble hand and the hand in rest. STRAIGHT HAND WITH THUMB DKOOPED. 161 Now, the first degree of deviation from this ortho- extended hand, which is the type of strength, is seen in the posture of the thumb metacarpal bone. The " ortho-extended hand with thumb di-ooped "-^ Fig. 23.— The Straight Extended Hand with Thnmh drooped. this is a departure from the normal in the direction of weakness, the first and most mobile, and the most specialized bone of the metacarpus being adducted, as in the convulsive hand, the feeble hand, and the hand in rest. This is often seen in a man who is strong and well, but tired with a day's work. Fig. 24.— Hand intermediate between the Hand In Rest and the Straight Hand. The two next modes of expression by hand pos- tures that have to be described are those which earliest attracted my especial attention. It was the clinical value of a knowledge of the " nervous hand " that encouraged me to pursue these investi- gations on expression. Having during some years given special study to the conditions of the nerve-system in children, my 162 PHYSICAL EXPKESSION. attention "was especially drawn to the various pos- tures presented by children brought to me for exami- nation at the East London Hospital for Children, and from 1878 I kept notes of the spontaneous pos- tures observed.* The children were requested to hold out their hands, and the passive condition or posture of each hand was noted. At first it was difficult to describe the postures in anatomical lan- guage, though some were seen to be characteristic of certain nerve conditions. In 1879, while visit- ing Florence, it struck me that the posture of the hands of the Venus de' Medici t was exactly similar to the posture so often seen in nervous children. Later in the year, at the British Museum, I saw the English Venus side by side with the Diana — feminine coyness and nervousness represented side, by side with the expression of energy and strength — and the contrast of the hand postures showed them to be in direct antithesis. While looking at the marble hands it became easy to describe their anatomical postures. In the "nervous hand" the wrist is slightly flexed or bent, the metacarpo-phalangeal joints are moderately hyper-extended (extended beyond the straight line), the first and second internodes being either slightly flexed or kept straight. The thumb is extended backwards, and somewhat abducted from the fingers. This spontaneous posture I have * " Spontaneous Postures of the Hand considered as indications of the Conditions of the Brain." Read before the Koyal Medical and Chirurgical Society of London, November 28, 1882. See " Brain," part xxiii. t See Fig. 32, p. 296. THE NERVOUS HAND. 163 seen, and others with me, in hundreds of cases usually in nervous children, bad sleepers, those convalescent from chorea, etc. The same posture is sometimes seen in partial hemiplegia. The pos- ture is often bilateral, but is usually unequally represented on the two sides; it is also often seen on one side only, especially in children convalescent from hemichorea,. Fig. 25. — The Nervous Hand. Another posture of the hand less frequently seen in pathological states, I described under the name of the " energetic hand," and since so doing I have found the posture figured by H. Meillet of Paris, with the note " Main dite du prddicateur em- phatique. La Salp^trifere, service de M. Charcot, salle Saint-Paul, No. 6, Ismdrie Angot." It is there figured as a permanent deformity resulting from brain disease. Dr. Little also figures this posture as due to spastic contraction. In this posture the wrist is extended, and the small joints are all in flexion. Here analysis shows the large joint, the wrist, in extension, tJie opposite to the condition of 164 PHYSICAL EXPRESSION. weakness, and this extension of the large joint gives to the posture the indication of excitement in the nerve-mechanism. The small joints are all flexed, as seen in the hand of a man in sleep or resting, and this gives the posture the indication of strength or activity with rest. Fig. 26.— The Energetic Hand. Anatomical analysis shows the " energetic hand " to be the antithesis of the " nervous hand." Nervous Hand. Energetic Hand. Wrist Flexed Extended Metacarpo-plmlangeals .... Extended Flexed First and second intemodes . . Flexed „ Thumb, metacarpo-phalangeal . Extended „ „ intemode „ „ Phalanges, relative position . . Slightly abducted Adducted The physiological expressions of the two postures are also opposites. This suggests another principle of use in explain- ing the meaning of certain postures. The principle of antithesis * may be enunciated as follows :. " In * Charles Darwin uses the principle of antithesis to oxplain many modes of expression. Seo " Expression of the Emotions," p. 28. THK CAUSE OF POSTURES. 165 opposite conditions of the nerve-mechanism pro- ducing the postures of a joint, the postures will be opposite or antithetical;" e.g. in a weak or inactive condition of the nerve-mechanism govern- ing the wrist, flexion results ; this would lead us to anticipate that in an excited condition of this piece of nerve-mechanism we should find the wrist extended. , The postures of a limb depend in their immediate mechanism upon the resultant action of opposing muscles, the relative tone of the antagonistic flexors and extensors, the adductors and abductors, etc. Various views may be held with regard to the nerve-mechanism which regulates the contraction of opposing sets of muscles. That mechanism may be considered a line of reflex action regulating the action of the muscles, or the balance may be con- sidered due to some other kind of nerve-mechanism. In any case it will, I think, be granted that some portion of the central nerve-system is the cause of that balance of the muscles that produces the posture, and therefore the posture is an index of the condition of that central nerve-mechanism. In examining the condition of the nerve-system in children, it has for several years been my habit to observe what spontaneous posture would be assumed by the hand when the forearm was held out.* Let a weak, nervous child be requested to hold out her hands in front on a level with the shoulder in a prone position. The limb is now * See "Brain," part Xi. ; and British Medical Journal, De- cember 6, 1879. 166 PHYSICAL EXPBESSION. free or disengaged, and the posture assumed by the hand is in most cases, I believe, the spontaneous outcome of the action of the nerve-centres. From continued observation of spontaneous pos- tures, and after frequently trying what spontaneous posture would be assumed by the free hand in various subjects, cases of weakness, strong men, feeble women, nervous children, an empirical idea was obtained as to the indication of each posture. Then comparison, analysis, and analogy enabled me to suggest some definite principles. In seeking a rational explanation of this posture, I first tried to find a solution by looking at it after the manner in which Charles Darwin made most of his observa- tions upon postures. Cases were looked for where this posture of the hand was assumed or brought about for some useful purpose, or its occurrence was attended with some kind of amelioration of weak- ness. Then this "nervous hand" was seen, in a hand not free or disengaged, in people who, stand- ing, lean a little forward with the outspread hands resting on the table for support. This hand seeking rest droops at the wrist, and then if the stimulus to the muscles is weak, as the weight of the trunk bears upon the resting hands, hyper-extension of the metacarpo-phalangeal joints and of the thumb is mechanically brought about. If this be accepted as an explanation, the argument stands thus : — 1. Observation shows that when a man is tired or weak he often rests his hands as described. 2. The nerve-mechanism corresponding to the hand is thrown into the special condition corre- EXPLANATION OF THE NERVOUS HAND. 167 spending to the "nervous hand," and thus that posture is mechanically brough about. 3. The nerve-mechanism corresponding to the hand falls spontaneously into the condition corre- sponding to the "nervous hand" when the man is tired or -weak. 4. When the hand of a weak man is held out free, its nerve-machanism spontaneously places it in the " nervous posture." The attempt at explanation may be made again, commencing with the principle of analysis and then applying the principle of analogy. Anatomical analysis shows that this "nervous hand " presents two principle elementary conditions : (1) Flexion or drooping of the wrist. (2) Hyper-extension of the metacarpo-phalangeal (small) joints. So much for analysis, now as to analogy. Looking for analogy between postures, flexion or drooping of the wrist may be seen, as in a hand that is resting, in a hand that is passively held out while the patient is deeply asleep, or in deep coma, or in a paralyzed arm. It is probable, then, that the wrist flexion indicates the weakness of the " nervous hand." Hyper-extension of the metacarpo-phalangeal joints and thumb may be seen as a temporary con- dition in subsultus tendinum and in chorea. In all these cases the unstable condition of the nerve- mechanism is indicated by the extensor movements of small parts. Now, looking at the elementary conditions shown 168 PHYSICAL EXPEESSION. by analysis to constitute the " nervous hand," and the probable indication of the conditions analogous to these, we get some kind of explanation of this posture. The drooping wrist is analogous to that seen in hemiplegia; the hyper-extension of the knuckles and thumb is analogous to conditions such as chorea and subsultus tendinum. This appears a more rational explanation than that first given, and the methods of analysis and analogy give some indication of the physiological significance of the posture. Something very like this posture of the hand is indicated by Dr. Little in his work on deformities, 1853, as the result of "spastic con- traction." My present object is to show that spontaneous postures may be studied with advantage as indica- tions of the conditions of the brain. As to the principles involved in these inquiries. A primary postulate, involved in the following principles, is that — "If we see some spontaneous nerve-muscular action often repeated in the same and in difierent subjects, it may be assumed that there is some nerve- centre, or nerve-mechanism, corresponding which can act independently." In any particular instance the assumption of the existence of such a centre or piece of nerve-mechanism would be strengthened if it could be shown that there are cases of excitation and cases of paralysis of such hypothetical centre. The following suggestions are ofiered as to the tneihods of determining whether a posture is the out- come of the spontaneous action of the nerve-centres. NEEVE-MUSCULAR POSTURES. 169 A posture observed can only be considered as the outcome of the spontaneous action of the nerve- mechanism when the limb or part is free and- dis- engaged. If the muscles of the hand are engaged in holding an object, or in an act of manipulation, the postures of the hand are not simply the out- come of the spontaneous action of the nerve- mechanism. • Postures are frequently seen accompanying, and apparently caused by, demonstrable brain-disease; as examples, the "convulsive hand," cerebral facial palsy.* When these postures occur otherwise, apparently spontaneously, they may be looked upon as nerve-muscular signs produced by the nerve-mechanism corresponding. Postures which are frequently seen in very young children and infants are certainly spontaneous. Postures seen to be frequently repeated in many such young subjects are probably spontaneous nerve-muscular actions. With regard to postures thus observed in many infants, it is probable that the piece of nerve-mechanism corresponding is well developed, and rendered very definite so as to be easily excited to spontaneous action. When a posture seen in an adult is found to be analogous to one often seen in infants, the probability of its spontaneous origin is strength- ened. Postures of disengaged parts, still observed in man, and frequently represented in ancient art,t * See pp. 108, 109, Figs. 10, 11. t See Fig. 35, p. 300. 9 170 PHYSICAL EXPRESSION. are probably of frequent spontaneous occurrence, and highly characteristic nerve-muscular postures. The application of the "principles of analysis" may assist in 'determining whether a certain posture observed is probably the outcome of the spontaneous action of the nerve-centres. In these studies care must be taken to avoid certain errors from attributing all postures to the action of the central nerve-mechanism. Postures may be due to joint-disease, especially arthritis deformans. M. Charcot carefully differen- tiates between this deformity and the posture he has described as the " writing hand " often seen in paralysis agitans. Postures may be due to local causes — tumours, inflammation, etc. Postures may be determined by organic condi- tions, such as difficulties in the respiratory and circulatory organs causing orthopnoea. Sir C. Bell drew attention to this matter in his critical analysis of the posture of the Dying Gladiator.* Such postures are not the direct effect of the spontaneous action of the nerve-centres. Gravity may be a factor in the causation of postures, whether the member be "free" or " engaged," thus : in the figure of Hercules at rest,t he leans on a vertical club to support his body, and the posture of the right arm is determined mainly by gravity. In a paretic arm such as is often seen in chorea, or from brain disease, the wrist will droop into flexion if the forearm is held out ' See p. 303. t See p. 305. FALLACIES AS TO MEANING OF POSTUKES. 171 prone, but will fall into extension if the forearm is held out supine. Dorsal decubitus results from gravity, together with general palsy of the motor nerve-mechanism. Postures may be due to local nerve injury or disease, thus : injury to the facial nerve ; * injury to the musculo-spiral nerve; a gumma pressing upon the third crania]> nerve, may produce certain pos- tures of the parts supplied by these nerves, such postures not depending upon the condition of the nerve-centres. Postures may be due to rigid muscular con- traction dependent upon permanent brain lesion, such as descending sclerosis. Such cases should be kept separate from the postures due to a temporary, it may be momentary, condition of the central nerve-mechanism. It is hoped that some proofs have been given that the study of spontaneous pos- tures as indications of the condition of the brain is useful, and that it may be considered as one of the exact methods of studying the nervous system in its physiological and pathological conditions. The subjoined tables contain descriptions of eight typical postures, applying the " principles " to the study of each. • See Fig. 27, p. 202, representing facial palsy. 172 PHTSICAX EXPRESSION. a S-o 1 •2 ri> 0> T3 ^ v;^ K < POSTUKES OF THE UPPER EXTREMITy. 173 fa 02 u "5.2 M 2 3 (U Oi e 1= g-e SSj . p, g m IH n ^ a £ m ■♦J £.£> U O U »0 CO •a g SS "s 1 o! g; a oi B " C "g.a^ s.s g s mS S -e a -9 3 43 d = a o c A q-t S.S I >- S'O p 2 g g g oqa g g* g ^ X -S .5 § ^ " „ -M a •K M-a S3 Mg S g a Is a--. B-3 &« : '§ fn -S r. 1 1 J z 0) t3 0) e Sg n 1 a a ■» p K oT « . 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