A good example of motor adjustments, which though marginal are certainly not unfelt in their net results, is afforded by the production of the voice in singing. And here no description nor explanation is of much service. We sound or sing a note to a child. At first the attempts to reproduce the same note are perhaps somewhat wild. The voice pitches now here now there, now too high and now too low. But after some attempts, and often some sliding, the note is caught, and is then held to with some steadiness, if the child have a musical ear. Gradually control is gained over the laryngeal apparatus, until the visual stimuli of a vocal score suggest with accuracy and rapidity a sequence of intervals, each of which involves a special motor adjustment. And these motor adjustments are certainly not unfelt. I do not mean merely that the whole process of learning to sing at sight would be inexplicable if they were unfelt; I mean that I personally feel them with great distinctness. If I am looking over some new songs in a music-shop, I quite clearly feel the motor adjustments necessary for singing the notes set down, though I do not murmur a sound. And if the song runs up beyond my vocal range, I have an uncomfortable strained sensation in the throat. For every note I can sing I have a separate motor-sensation; and this sensation, though for psychology an undecomposable element in consciousness, is physiologically the net result of a great number of impulses from the several parts of the larynx. And the acquisition of skill in singing at sight involves the nice correlation of these motor-sensations, with certain visual sensations due to stimuli from the vocal score, and certain auditory sensations which accompany the production of the voice. Of course this analysis is incomplete. Motorsensations accompanying the breathing, and the position of the tongue, lips, and mouth organs, require delicate correlation with the laryngeal and auditory sensations; and no doubt there are further subsidiary correlations.

I have said so much concerning skill, because, in the correlations it involves, we have some of the most delicate and finished results of the selective synthesis of senseexperience or consentience. And I have said so much concerning the human aspects of skill because it is necessary, in accordance with the method of interpretation adopted in this work, to study the psychology of skill at first hand in order that we may infer what takes place in the minds of animals. I think there can be no question that the acquisition of perfected skill by the dog or the elephant, by the beaver, the swift, or the snake-bird, is effected in analogous ways to those by which it is effected in man, excepting in so far as in man there is a certain amount of guidance by description and explanation. This factor is certainly absent in animals. No one ever taught a dog to perform the simplest trick by describing or explaining how it is done. Animals have to rely first on the internal promptings to satisfy hunger or other emotional affections; secondly, on parental guidance; and thirdly, on the influence of what has been termed tradition—that is, the continuity of habit in a community. Animals which live in herds, packs, or flocks, are born into a community which perform certain actions in certain ways, and through imitation of these traditional proceedings they have a strong tendency to act in like manner. But the acquisition of skill, however prompted, is essentially the individual perfecting under conscious control, of activities, the basis of which is an inherited aptitude. This perfecting involves the correlation of sense-data, visual, auditory, olfactory, and so forth, on the one hand, and motor on the other hand; and it is furthermore inexplicable in the absence of motorsensations which enter, if only marginally, into the field of conscious experience.

It is through skill, and the application of skill, that animals deal so successfully with their environment. For

when skill has been acquired its application is based on association under the varied and varying conditions of sense-experience. The application is essentially a practical matter in accordance with the needs and requirements of a life that is full of vicissitudes. By the more intelligent animals every favourable association is utilized and becomes a factor in the further development of experiIn future chapters the nature and range of intelligent adaptation to circumstances will come under our notice and will receive fuller illustration. All such intelligent adaptation falls within the range of sense-experience, which deals with sense-data of all kinds, and correlates them for the purposes of practical guidance, thus enabling the animal to carry out its life-activities and to meet the varying exigencies of a complex environment.

ence.

In conclusion, it should be remembered that both in the delicacy of their sensory endowment and in the ability to deal with that environment by sense-experience, animals are probably in some respects distinctly in advance of man. Witness the delicacy of the sense of smell in some animals enabling them to do that which no man could do so well. I think it not at all improbable that their powers of rapid flight in the free medium of the air have induced in birds a delicacy and high specialization of the sense of direction of the movements of the body as a whole, of which we slow treaders of the ground can scarcely form any conception. And this perhaps is a factor in that most difficult and complex question,-one that involves a good deal more than instinct only, I mean the migration of birds. Very possibly our own endowment, in this sense of direction of movement, is very degenerate; still more probably we civilized folk do not make much use of the sensory endowment that we have, relying rather on our knowledge through spatial perceptions and conceptions than on our native powers of senseexperience. Savages who in their daily life make more use

of these native powers, and explorers who are led by circumstances to cultivate these powers, have a sense of direction that the city clerk has allowed to lie dormant and unused. He does not cultivate the delicate use of his membranous labyrinth, with its semi-circular canals. Animals do cultivate the use of this sense-organ, and probably elements contributed thereby enter into the organised and correlated field of sense-experience in a way at which we can but dimly guess.

WE

CHAPTER XI.

AUTOMATISM AND CONTROL.

E have already learnt that from all parts of the surface of the body,-from eye, ear, nose, and palate, from the muscles, joints, and internal viscera,-there run nerves—ingoing or afferent nerves—which are in direct connection with the spinal cord and the brain. These nerves are the channels along which impulses may be transmitted to the nerve-centres. Within these nerve-centres molecular disturbances are thereby caused, as the result of which further impulses are transmitted down other nerves --outgoing or efferent nerves-to muscles, which are thus stimulated to contraction; or to glands, which are stimulated to secretion. It is generally believed, as the result of many observations and experiments, that consciousness is not associated with the transmission of impulses along the nerves; but that when the molecular thrill reaches the brain, or some part of it, there, under appropriate conditions, consciousness emerges.

The group of structures consisting of (1) afferent nerve, with its sensory termination, (2) nerve-centre, and (3) efferent nerve, with its motor or other termination, is spoken of as the nervous arc. It is called into activity by a stimulus applied to the sensory termination of the afferent nerve, and the motor or other result of its activity is spoken of as the response. The response is always more or less complex, involving the balanced and nicely regulated action of several, often many, muscles. And it is clear that the balanced action of several muscles must be due to the transmission to