Nothing better illustrates this distinction than the difference between the fore foot of animals and the hu- man hand. The first begins as a fin or paddle or is armed with a hoof, and is used solely for locomotion. Some carnivora with claws use the fore limb also for holding as well as tearing, and others for digging. Arboreal life seems to have almost created the simian hand and to have wrought a revolution in the form and use of the forearm and its accessory organs, the fingers. Apes and other tree-climbing creatures must not only adjust their pre- hensile organ to a wide variety of distances and sizes of branches, but must use the hands more or less freely for picking, transporting, and eating fruit; and this has probably been a prime factor in lifting man to the erect position, without which human intelligence as we know it could have hardly been possible. ' ' When we attempt to measure the gap between man and the lower animals in terms of the form of movement, the wonder is no less great than when we use the term of mentality." ^ The degree of approximation to human intelligence in anthro- poid animals follows very closely the degree of approxi- mation to human movements.
The gradual acquirement of the erect position by the human infant admirably repeats this long phylogenetic evolution.^ At first the limbs are of almost no use in 1 F. Burk in From Fundamental to Accessory. Pedagogical Semi- 2 Creeping and Walking, by A. W. Trettien. American Journal of Psychology, October, 1900, vol. 12, pp. 1-57.
10 MUSCLES AND MOTOR POWERS IN GENERAL locomotion, but the fundamental trunk muscles with those that move the large joints are more or less spas- modically active. Then comes creeping, with use of the hip muscles, while all below the knee is useless, as also are the fingers. Slowly the leg and foot are degraded to locomotion, slowly the great toe becomes more limited in its action, the thumb increases in flexibility and strength of opposition, and the fingers grow more mobile and controllable. As the body slowly assumes the verti- cal attitude, the form of the chest changes till its greatest diameter is transverse instead of from front to back. The shoulder-blades are less parallel than in quadrupeds, and spread out till they approximate the same plane. This gives the arm freedom of movement laterally, so that it can be rotated one hundred and eighty degrees in man as contrasted to one hundred degrees in apes, thus giving man the command of almost any point within a sphere of which the two arms are radii. The power of grasping was partly developed from and partly added to the old locomotor function of the fore limbs; the jerky aimless automatisms, as well as the slow rhythmic flexion and extension of the fingers and hand, movements which are perhaps survivals of arboreal or of even earlier aquatic life, are coordinated; and the bilateral and si- multaneous rhythmic movements of the heavier muscles are supplemented by the more finely adjusted and spe- cialized activities which as the end of the growth period is approached are detci-mined less by heredity and more by environment. In a sense, a child or a man is the sum total of his movements or tendencies to move; and nature and instinct chiefly determine the basal, and edu- cation the accessory parts of our activities.
The entire accessory system is thus of vital impor- tance for the development of all of the arts of expression.
11 YOUTH: ITS EDUCATION, REGIMEN, AND HYGIENE These smaller muscles might almost be called organs of thought. Their tension is modified with the faintest change of soul, such as is seen in accent, inflection, facial expressions, handwriting, and many forms of so-called mind-reading, which, in fact, is always muscle-reading. The day-laborer of low intelligence, with a practical vocabulary of not over five hundred words, who can hardly move each of his fingers without moving others or all of them, who can not move his brows or corrugate his forehead at will, and whose inflection is very monoto- nous, illustrates a condition of arrest or atrophy of this later, finer, accessory system of muscles. On the other hand, the child, precocious in any or all of these later respects, is very liable to be undeveloped in the larger and more fundamental parts and functions. The full unfoldment of each is, in fact, an inexorable condition precedent for the normal development to full and abid- ing maturity of the higher and more refined muscularity, just as conversely the awkwardness and clumsiness of adolescence mark a temporary loss of balance in the opposite direction. If this general conception be correct, then nature does not finish the basis of her pyramid in the way Ross, Mercier, and others have assumed, but lays a part of the foundation and, after carrying it to an apex, normally goes back and adds to the foundation to carry up the apex still higher and, if prevented from so doing, expends her energy in building the apex up at a sharper angle till instability results. School and kinder- ■ garten often lay a disproportionate strain on the tiny ac- cessory muscles, weighing altogether but a few ounces, that wag the tongue, move the pen, and do fine work re- quiring accuracy. But still at this stage prolonged work requiring great accuracy is irksome and brings dangers homologous to those caused by too much fine work in the 12 7 / MUSCLES AND MOTOR POWERS IN GENERAL kindergarten before the first adjustment of large to small muscles, which lasts until adolescence, is estab- lished. Then disproportion between function and growth often causes symptoms of chorea. The chief danger is arrest of the development and control of the smaller muscles. Many occupations and forms of athlet- ics, on the contrary, place the stress mainly upon groups of fundamental muscles to the neglect of finer motor pos- sibilities. Some who excel in heavy athletics no doubt coarsen their motor reactions, become not only inexact and heavy but unresponsive to finer stimuli, as if the large muscles were hypertrophied and the small ones ar- rested. On the other hand, many young men, and prob- ably more young women, expend too little of their avail- able active energy upon basal and massive muscle work, and cultivate too much, and above all too early, the delicate responsive work. This is, perhaps, the best physiological characterization of precocity and issues in excessive nervous and muscular irritability. The great influx of muscular vigor that unfolds during adolescent years and which was originally not only necessary to suc- cessful propagation, but expressive of virility, seems to be a very plastic quantity, so that motor regimen and exercise at this stage is probably more important and all-conditioning for mentality, sexuality, and health than at any other period of life. Intensity, and for a time a spurty diathesis, is as instinctive and desirable as are the copious minor automatisms which spontaneously give the alphabet out of which complex and finer motor series are later spelled by the conscious will. Mercier and others have pointed out that, as most skilled labor, so school work and modern activities in civilized life generally lay premature and disproportionate strains upon those kinds of movement requiring exactness. Stress upon basal 13 YOUTH: ITS EDUCATIOxN, REGIMEN, AND HYGIENE movements is not only compensating but is of higher therapeutic value against the disorders of the accessory system; it constitutes the best cure or prophylactic for fidgets and tense states, and directly develops poise, con- trol, and psycho-physical equilibrium. Even when con- tractions reach choreic intensity the best treatment is to throw activities down the scale that measures the differ- ence between primary and secondary movements and to make the former predominate.
The number of movements, the frequency with which they are repeated, their diversity, the number of combi- nations, and their total kinetic quantum in young chil- dren, whether we consider movements of the body as a whole, fundamental movements of large limbs, or finer accessory motions, is amazing. Nearly every external stimulus is answered by a motor response. Dresslar ^ ob- served a thirteen months' old baby for four hours, and found, to follow Preyer's classification, impulsive or spontaneous, reflex, instinctive, imitative, inhibitive, ex- pressive, and even deliberative movements, with marked satisfaction in rhythm, attempts to do almost anything which appealed to him, and almost inexhaustible efferent resources. A friend has tried to record every word ut- tered by a four-year-old girl during a portion of a day, and finds nothing less than verbigerations. A teacher noted the activities of a fourteen-year-old boy during the study time of a single school day,^ with similar results.
Lindley ' studied 897 common motor automatisms in children, which he divided into 92 classes: 45 in the re- 1 A Morning Observation of a Baby. Pedagogical Seminary, Decem- 2 Kate Carman. Notes on School Activity. Pedagogical Seminary, 3 A Preliminary Study of Some of the Motor Phenomena of Mental Effort. American Journal of Psychology, July, 1896, vol. 7, pp. 491-517.
14 MUSCLES AND MOTOR POWERS IN GENERAL gion of the head, 20 in the feet and legs, 19 in the hands and fingers. Arranged in the order of frequency with which each was found, the list stood as follows: fingers, feet, lips, tongue, head, body, hands, mouth, eyes, jaws, legs, forehead, face, arms, ears. In the last five alone adolescents exceeded children, the latter excelling the former most in those of head, mouth, legs, and tongue, in this order. The writer believes that there are many more automatisms than appeared in his returns.
School life, especially in the lower grades, is a rich field for the study of these activities. They are familiar, as licking things, clicking with the tongue, grinding the teeth, scratching, tapping, twirling a lock of hair or chewing it, biting the nails (Berillon's onychophagia), shrugging, corrugating, pulling buttons or twisting garments, strings, etc., twirling pencils, thumbs, rotat- ing, nodding and shaking the head, squinting and wink- ing, swaying, pouting and grimacing, scraping the floor, rubbing hands, stroking, patting, flicking the fingers, wagging, snapping the fingers, snuffling, squinting, pick- ing the face, interlacing the fingers, cracking the joints, finger plays, biting and nibbling, trotting the leg, suck- ing things, etc.
The average number of automatisms per 100 persons Smith found to be in children 176, in adolescents 110. Swaying is chiefly with children; playing and drumming with the fingers is more common among adolescents; the movements of fingers and feet decline little with age, and those of eyes and forehead increase, which is significant for the development of attention. Girls excel greatly in swaying, and also, although less, in finger automatism; and boys lead in movements of tongue, feet, and hands. Such movements increase, with too much sitting, inten- sity of effort, such as to fix attention, and vary with the 15 YOUTH: ITS EDUCATION, REGIMEN, AND HYGIENE nature of the activity willed, but involve few muscles directly used in a given task. They increase up the kindergarten grades and fall off rapidly in the primary grades; are greater with'tasks requiring fine and exact movements than with those involving large movements. Automatisms are often a sign of the difficulty of tasks. The restlessness that they often express is one of the com- monest signs of fatigue. They are mostly in the acces- sory muscles, while those of the fundamental muscles (body, legs, and arms) disappear rapidly with age; those of eye, brow, and jaw show greatest increase with age, but their frequency in general declines with growing maturity, although there is increased frequency of cer- tain specialized contractions, which indicate the gradual settling of expression in the face.
Often such movements pass over by insensible grada- tion into the morbid automatism of chorea, and in yet lower levels of decay we see them in the aimless picking and plucking movements of the fingers of the sick. In idiots ^ arrest of higher powers often goes with hyper- trophy of these movements, as seen in head-beaters (as if, just as nature impels those partially blind to rub the eyes for " light-hunger," so it prompts the feeble- minded to strike the head for cerebrations), rockers, rackers, shakers, biters, etc. Movements often pass to fixed attitudes and postures of limbs or body, disturbing the normal balance between flexors and extensors, the significance of which as nerve signs or exponents of habitual brain states and tensions Warner has so admir- ably shown.
Abundance and vigor of automatic movements are desirable, and even a considerable degree of restlessness 1 G. E. Johnson. Psychology and Pedagogy of Feeble-Minded Children. Pedagogical Seminary, October, 1895, vol. 3, pp. 246-301.
16 MUSCLES AND MOTOR POWERS IN GENERAL is a good sign in young children. ]Many of what are now often called nerve signs and even choreic symp- toms, the fidgetiness in school on cloudy days and often after a vacation, the motor superfluities of awkwardness, embarrassment, extreme effort, excitement, fatigue, sleepiness, etc., are simply the forms in which we re- ceive the full momentum of heredity and mark a natural richness of the raw material of intellect, feel- ing, and especially of will. Hence they must be abun- dant. All parts should act in all possible w^ays at first and untrammeled by the activity of all other parts and functions. Some of these activities are more essential for growth in size than are later and more conscious movements. Here as everywhere the rule holds that powers themselves must be unfolded before the ability to check or even to use them can develop. All move- ments arising from spontaneous activity of nerve cells or centers must be made in order even to avoid the atrophy of disease. Not only so, but this purer kind of innateness must often be helped out to some extent in some children by stimulating reflexes; a rich and wdde repertory of sensation must be made familiar; more or less and very guarded, watched and limited experiences of hunger, thirst, cold, heat, tastes, sounds, smells, colors, brightnesses, tactile irritations, and perhaps even occasional tickling and pain to play off the vastly com- plex function of laughing, crying, etc., may in some cases be judicious. Conscious and unconscious imita- tion or repetition of every sort of copy may also help to establish the immediate and low-level connection be- tween afferent and efferent processes that brings the organism into direct rapport and harmony with the whole world of sense. Perhaps the more rankly and in- dependently they are developed to full functional in- 17 Syy YOUTH: ITS EDUCATION, REGIMEN, AND HYGIENE j tegrity, each in its season, if we only knew that sea- vi son, the better. Premature control by higher centers, or coordination into higher compounds of habits and ordered serial activities, is repressive and wasteful, and the mature will of which they are components, or which must at least domesticate them, is stronger and more forcible if this serial stage is not unduly abridged. / But, secondly, many, if not most, of these activities ^|when developed a little, group after group, as they arise, must be controlled, checked, and organized into higher and often more serial compounds. The inhibiting func- tions are at first hard. In trying to sit still the child sets its teeth, holds the breath, clenches its fists and per- haps makes every muscle tense with a great effort that very soon exhausts. This repressive function is prob- ably not worked from special nervous centers, nor can we speak with confidence of collisions with " sums of arrest " in a sense analogous to that of Herbart, or of stimuli that normally cause catabolic molecular proc- esses in the cells, being mysteriously diverted to pro- duce increased instability or anabolic lability in the sense of Wundt's Mechanik der N erven. 'The concept now suggested by many facts is that inhibition is irradi- ation or long circuiting to higher and more complex brain areas, so that the energy, whether spontaneous or reflex, is diverted to be used elsewhere. These combina- tions are of a higher order, more remote from reflex action, and modified by some Jacksonian third level. ^ 1 Dr. Hughlings Jackson, the eminent English pathologist, was the first to make practical application of the evolutionary theory of the nervous system to the diagnosis and treatment of epilepsies and mental diseases. The practical success of this application was so great that the Hughlings-Jackson "three-level theory" is now the established basis of English diagnosis. He conceived the nervous mechanism as composed of three systems, arranged in the form of a hierarchy, the higher including 18 MUSCLES AND MOTOR POWERS IN GENERAL Action is now not from independent centers, but these are slowly associated, so that excitation may flow off from one point to any other and any reaction may re- sult from any stimulus.
The more unified the brain the less it suffers from localization, and the lower is the level to which any one function can exhaust the whole. The tendency of each group of cells to discharge or overflow into those of lower tension than themselves increases as correspond- ence in time and space widens. The more one of a number of activities gains in power to draw on all the brain, or the more readily the active parts are fed at cost of the resting parts, the less is rest to be found in change from one of these activities to another, and the less do concentration and specialization prove to be dan- gerous. Before, the aim was to wake all parts to functhe lower, and yet each having a certain degree of independence. The first level represents the type of simplest reflex and involuntary move- ment and is localized in the gray matter of the spinal cord, medulla, and pons. The second, or middle level, comprises those structures which receive sensory impulses from the cells of the lowest level instead of directly from the periphery or the non-nervous tissues. The motor cells of this middle level also discharge into the motor mechanisms of the lowest level. Jackson located these middle level structures in the cortex of the central convolutions, the basal ganglia and the centers of the special senses in the cortex. The highest level bears the same relation to the middle level that it bears to the lowest i.e., no continuous connec- tion between the highest and the lowest level is assumed; the structures of the middle level mediate between them as a system of relays. Accord- ing to this hierarchical arrangement of the nervous system, the lowest level which is the simplest and oldest "contains the mechanism for the simple fundamental movements in reflexes and involuntary reactions. The second level regroups these simple movements by combinations and associations of cortical structures in wider, more complex mechanisms, producing a higher class of movements. The highest level unifies the whole nervous system and, according to Jackson, is the anatomical basis of mind."
For a fuller account of this theory see Burk: From Fundamental to Accessory in the Nervous System and of Movements. Pedagogical Seminary, October, 1898, vol. 6, pp. 17-23.
19 YOUTH: ITS EDUCATION, REGIMEN, AND HYGIENE tion; now it is to connect them. Intensity of this cross- section activity now tends to unity, so that all parts of the brain energize together. In a brain with this switch- board function well organized, each reaction has grown independent of its own stimulus and may result from any stimulation, and each act, e. g., a finger movement of a peculiar nature, may tire the whole brain. This helps us to understand why brain-workers so often excel laborers not only in sudden dynamometric strength test, but in sustained and long-enduring effort. In a good brain or in a good machine, power may thus be de- veloped over a large surface, and all of it applied to a small one, and hence the dangers of specialization are lessened in exact proportion as the elements of our ego are thus compacted together. It is in the variety and delicacy of these combinations and all that they imply, far more than in the elements of which they are com- posed, that man rises farthest above the higher animals; and of these powers later adolescence is the golden age. The aimless and archaic movements of infancy, whether massive and complex or in the form of isolated auto- matic tweaks or twinges, are thus, by slow processes of combined analysis and synthesis, involving changes as radical as any in all the world of growth, made over into habits and conduct that fit the world of present environment.
But, thirdly, this long process carried out with all degrees of completeness may be arrested at any unfin- ished stage. Some automatisms refuse to be controlled by the will, and both they and it are often overworked. Here we must distinguish constantly between (1) those growing rankly in order to be later organized under the will, and (2) those that have become feral after this domestication of them has lost power from disease or 20 MUSCLES AND MOTOR POWERS IN GENERAL fatigue, and (3) those that have never been subju- gated because the central power that should have used them to weave the texture of willed action — the proper language of complete manhood — was itself arrested or degenerate. With regard to many of these movements these distinctions can be made with confidence, and in some children more cer- tainly than in others. In childhood, before twelve, the efferent patterns should be developed into many i more or less indelible habits, and their colors set fast.!/ Motor specialties requiring exactness and grace like piano-playing, drawing, writing, pronunciation of a foreign tongue, dancing, acting, singing, and a host of virtuosities, must be well begun before the relative ar- rest of accessory growth at the dawn of the ephebic regeneration and before its great afflux of strength. The facts seem to show that children of this age, such as Hancock ^ described, who could not stand with feet close together and eyes closed without swaying much, could not walk backward, sit still half a minute, dress alone, tie two ends of a string together, interlace slats, wind thread, spin a top, stand on toes or heels, hop on each foot, drive a nail, roll a hoop, skate, hit fingers together rapidly in succession beginning at the little finger and