cised, unless there is some cerebral provision for augmentation and inhibition through control centres.

Among the commonest phenomena of the hypnotic state are suggested hyperæsthesia, on the one hand, and anesthesia on the other. In some cases the senses become, through suggestion, extraordinarily acute; in others, they seem to be abnormally dulled and blunted. In suggested hallucinations, under hypnosis, certain centres seem to be rendered extraordinarily susceptible to what we termed internal suggestion, so that the suggested images assume the vividness and insistency of impressions. It may be that these phenomena of the hypnotic state are partly caused by some at present unexplained influence on control centres, which may have for their function the augmentation or inhibition of the activity of those cerebral centres which are concerned in sense-experience.

It is now time to sum up the conclusions we have reached, and the suggestions we have made, with regard to automatism and control. The distinction I have drawn between automatic activities and controlled action is a sharp one. On the scheme I have put forward, automatic activities involve afferent impulses, co-ordinating centres, and efferent impulses. In the performance of these activities the organism is an automaton, and the whole matter so far is purely biological. Control of the motor activities involves, and must always involve, a loop-line, in the course of which there are developed certain centres, called control-centres, whose function it is either to augment or to inhibit the lower co-ordinating centres of the automatic mechanism. Associated with these control centres of the loop-line there are sensory centres, the functional activity of which is conscious or is associated with consciousness. These sensory centres are so disposed on the loop-line as to determine the nature of the activity, augmenting or inhibitory, of the control centres according to the emotional tone associated with the

functioning of the sensory centres. The sensory centres and the control centres are, in the higher vertebrates, situate in the cerebral hemispheres of the brain. So far the control is entirely motor; and so far there is much in the anatomy and physiology of the brain and central nervous system in support of the hypothesis here put forward. It is further suggested as a possibility-at present unsupported by, but so far as I know not negatived by, cerebral anatomy and physiology-that there may be cerebral centres for the control of the activity of the sensory centres. This hypothesis is put forward on purely psychological grounds. It is contended that if there is any control of cerebral activity and its mental concomitants,-if there is any faculty of attention other than that involved in the admitted motor control over the parts concerned in the reception of sensestimuli, this must be effected by means of a loop-line, with its associated control centres. For control is due to augmenting or inhibitory impulses, and such impulses must come from outside the system so controlled. This last pro

position may seem to stand in need of proof and elucidation, but I confess that it seems to me to be self-evident. For suppose a sensory centre be thrown into a state of activity, and that its functioning is associated with some form or mode of consciousness, I fail to see in what way it could be self-augmenting or self-inhibitory. We may assume that the activity is either painful or pleasurable. One can understand how its pleasurable or painful tone may differently affect a centre lying outside it with which it may communicate. But I am unable to understand how its pleasurable or painful tone could either increase or damp-down its own activity. Such a supposition appears to involve the illegitimate assumption, as I deem it, that the pleasure or the pain is something external to the activity, and can exercise control over it. Hence, for a psychology that endeavours to work hand-inhand with physiology, the control of any functioning centre

must be due to impulses, augmenting or inhibitory, coming to that centre from some other centre external to it.

Nothing has been said in this chapter concerning automatism or control in the higher invertebrates, such as the bee or the ant. Their actions seem to warrant the belief that in them, too, there is-besides the mechanism for automatic co-ordination—a mechanism of control. But at present nothing is known of definite control centres in these organisms, supposing such centres to exist. There is here a fruitful field for investigation, if we could only find a satisfactory point of departure.

In conclusion, it should be noted that control, whether it be motor-control or the suggested intra-cerebral control of the attention, should be psychologically distinguished from the sense of effort by which it is sometimes accompanied. Such a sense of effort is almost unquestionably a sensory product of the motor activities. The knit brow, slightly clenched teeth, somewhat strained respiration, and other motor concomitants, not only of motor-control but also of close and difficult thought and attention, are not without their psychical effects. And these we name effort. The part which motor impressions play in psychology, though often neglected, is of the utmost importance, as we have already seen in our discussion of Synthesis and Correlation.

I

CHAPTER XII.

INSTINCT AND INTELLIGENCE.

HAVE already described some of my experiments and observations on young chicks. I propose in this chapter to call these and other similar observations to my aid in endeavouring to make clear the relation of instinct to intelligence.

The eggs from which in due course the chicks emerged, were taken from the hen two or three days before the time of hatching was fulfilled, and were placed in an incubator. The little birds, which were for the most part of good crossed breeds, with strains of Plymouth Rock, Dorking, and Game, had therefore no parental help in gaining some experience of the world. I first directed my attention to their powers of seizing and swallowing. Selecting one about eighteen hours old for definite experiment, I placed before him three small pieces of white of egg, moving them about a little in front of him with a long pin to draw his attention to them. He soon pecked at one of these, and seized it at the fifth attempt, swallowing it a little awkwardly. The next he struck at the second attempt, but not fairly, so that it was thrust aside. Transferring his attention, therefore, to the third piece, he seized it and swallowed it at the third attempt. An hour later I tried him again with egg and crumb of bread. He generally struck the morsel at the second or third peck, though he sometimes failed to seize it. Once he seized and struck at the first attempt. The observations on this chick are, I think, typical. The pecking co-ordination in young chicks is fairly accurate, but by no means perfect,

at birth. They generally strike a little short. If the birds are kept for a longer period in the drawer of the incubator before they are given food,—and this may be done without injury to them, for they are hatched with a considerable store of food-yolk,-the pecking is rather more accurate, but not quite accurate.

Towards the close of their first day of active life, I caused a small fly to walk across my experimental poultry-yard in front of the chicks. Most of them took no notice; but one, whom I will call Blackie, followed and pecked at it. He caught it at the seventh attempt, and ate it; an hour later he caught another at the fourth peck, and subsequently a blue-bottle after twelve shots. This, however, he dropped and left uneaten. The others took no notice of flies, though they occasionally pecked at the disabled blue-bottle, without eating it. With a subsequent brood I tried throwing in a large fly, from which a portion of the wings had been, of course painlessly, removed. This was on their second day. One followed it, but then stopped and gave the characteristic danger note the first time I had heard it in the brood. Perhaps the buzzing noise made by the fly called forth this note of alarm. The same chick subsequently followed the fly, caught it after several pecks, and ate it.

These experiments and observations seem, therefore, to show that the skill in seizing is not perfect at birth, and that some practice is necessary. I have spoken so far only of morsels of food; but I soon found that the chicks would peck at almost any small object I placed before them, and if small enough, almost anything was eaten, or at least tested in the bill-grain, sand, crumbs, or little bits of a chopped-up wax match. All the chicks pecked repeatedly at the letters, especially the large capitals, on the newspaper with which the experimental yard in my study was floored. I threw to my chicks about equal proportions of millet, canary seed, groats, and pari. They were about equally pecked at, and