sights and sounds as growth and development advance. Movements are described as twitchings, when quick and seen in small parts, not effecting any useful purpose. Tremor is a term applied to the rapid and uniform movement of a part, the displacement being but slight; tremors are often of a rate of over 200 per minute. Reflex movements refer to the action of a special Reflex nerve-muscular apparatus, an afferent nerve-tract, and movement. the stimulus acting upon a sensory surface followed by movement. An essential character of what is commonly called a reflex movement is, that the movement quickly follows upon the stimulation, without any perceptible interval. If the eyeball is touched, the eyelids are quickly closed; this movement, and this alone, follows the impression produced as a reflex action. It will be seen that common reflex movements thus differ considerably from those we shall speak of as signs of intelligence. You may observe certain movements, which Movements are said to indicate intelligence; such are the most indicating interesting, but the most difficult to define. intelli It seems gence. that the purposive, or intelligent character of a series of movements is not due to its intrinsic attributes, but to its antecedents and sequents. The ordinary respiratory movements are not signs of intelligence, but when they are modified by sights and sounds around, as speech and laughter, they may indicate intelligence. Without giving an exact physical description of what is meant by intelligent movements, it may be said that their outcome is in harmony with the impression producing them. All movements in the body, however they be classified, are physical phenomena, and are due to physical antecedents. Voluntary and mental movements. Movements when Voluntary studied as signs of mental action are often said to be movements. voluntary, more or less voluntary in contrast to others described as automatic or spontaneous. Probably we cannot define a voluntary movement, but we may explain what conditions observed make us call it more or less voluntary. A movement following upon a word of command may be considered voluntary. Respiratory movements when occurring in a uniform series are not considered voluntary, but when the action is specially modified, as in speaking, or in singing, where the action is regulated by the sound of music, they are more voluntary. The movements of respiration in the infant are uniform, except when the child cries as an expression of pain or other mental emotion; in the adult many forms of emotion are expressed by variation in respiratory action, as in fear and anger. The modified respiratory actions termed sighing, laughing, singing, etc., may be signs of mental states, because they indicate nerve-states modified by special circumstances or antecedents. We consider such signs as mental phenomena, not so much on account of their (attributes or) intrinsic characters, as because of their relation to antecedents-the previous sight or sound. When no special antecedents of the act of sighing are known it is often said to be spontaneous, automatic, or involuntary. The voluntary character of a movement appears to be indicated partly by its relation to some antecedent impression and in part by its sequence. Useful acts are often considered to be voluntary, and these are such as produce some result. The voluntary voluntary character is also in part due to its control by some Mental acts are usually spontane ous move ments modified. The character. impression in place of spontaneous action; it may also be due to a change from one series of acts to another. In other cases the voluntary character is admitted because the act is obviously an example of delayed expression of some previous impression. As examples of voluntary and intelligent action, see-the ready reply, the exact copy, the act appropriate to the circumstance. move A complex series of movements of many parts in Series of succession, i. e. a compound series of movements follow- ments. ing some slight stimulus through eye or ear without reinforcement of brain action and producing some result or impression, is usually intelligent and voluntary; the more distinctly we see the action controlled by circumstances without reinforcement the more is it like an intelligent and voluntary action. We see a cat sitting An intellion the doorstep of a house, a dog comes by, the cat gent cat and a dog. simply moves behind the railings without any excess of movement or display of emotion-that is a voluntary and intelligent act, the outcome of experience or previous impressions. children's brains. Observation, comparison, and accurate study are Study of necessary in order to understand what is going on in children's brains. Looking at the whole body as to movements occurring in its parts, compare ratios of action in parts corresponding on the two sides; consider the ratio of movements of small parts to large parts in the arm and the head-the number of movements of digits in relation to those of the wrist and elbow, compared with movements of the eyes in relation to the head, etc. In this lecture, physical signs which you may observe Physical have been indicated, without any reference to their signs. significance. This has been done intentionally; I desire that you should observe facts, then think about them and draw conclusions. In the next lecture, descriptions will be given of various conditions seen in children, the terms employed being such as have been enumerated above. CHAPTER V. ness. DESCRIPTION OF VARIOUS CONDITIONS IN CHILDREN. WE commonly speak of various conditions as seen in children, such as consciousness, sleep, fatigue; such names are of scientific value when we have determined their physical connotation, or the physical signs by which we recognise the condition; each such term stands in place of the group of signs which express the condition. The most important condition of a child's brain is that Conscious indicated by the signs of Consciousness. You will find that the movements accompanying and expressing consciousness are such as are stimulated by circumstances acting upon its brain through the senses. If speaking to the child, or shewing him objects, is followed by his speaking, or by his hands moving towards the object, he is said to be conscious, or if he subsequently speaks of the object, he is said to have been conscious when the thing was presented to him, because we see that his nervecentres were impressed by the sight of it. If at night you stand by his bedside while he is sound asleep and unconscious, you see general absence of all movements except those of breathing; if you speak to him in a low voice, or hold a toy in front of him, he does not speak or There may be some movements of his limbs, or fingers, but such are not determined by objects around, they are not the outcome of impressions produced from without at the time of your observation. Sleep. move. Description of various conditions in Children. 73 Such absence of movement in a child when spoken to does not necessarily imply sleep, he may shew the signs of sleep given above, but next day he may repeat what you said to him when he was quiet, proving that he was impressionable, and that an impression was produced, but that the expression was delayed. Absence of movement Little force in sleep. in sleep indicates that nerve-currents are not passing, at expended any rate not with great strength, from the brain to the muscles. Nutrition of the brain is probably going on uniformly throughout, but no expenditure of force is taking place. It is often said there may be different depths of sleep; sleep may be full and complete, with Depth of loss of most forms of impressionability. In healthy sleep sleep. the tone of the circular muscles of the eyelids is sufficient to keep them closed, but in some weakly children they remain half open, shewing a part of the white portion of the eye. If you gently raise the arm, by one finger in the wrist-band, the hand of the child in sleep falls into the posture of rest (see fig. 5); there may possibly be some twitching of the fingers. You may hear the child grinding his teeth, this is not a good sign. Tooth- Toothgrinding is due to the united action of the muscles of grinding. mastication moving the lower jaw; these muscles are supplied by the motor division of the fifth nerve of the brain, and the sensory fibres of that nerve supply the membranes of the brain, as well as parts outside the head. Tooth-grinding shews brain irritation. Dreams may be Dreams. supposed to trouble a child when he cries out during his sleep, but the words he says may have no relation in fact with his work during the day. Restless nights mean a brain not perfectly nourished during sleep. The importance of imperfect sleep is to be measured by sequential 1 See Anatomy of Movement, p. 33, as to eye movements in sleep. |