Our description of attention is so far complete; but there are two further questions that naturally occur. Do we not attend to what ‘interests’ us? In that case, however, attention must imply feeling. And is not sustained attention tiring? In that case, attention would seem to imply muscular sensation. These are undoubtedly points to be considered, and we must try to get at the facts. _Are feeling and kinæsthesis necessary in attention_, or are they merely chance accompaniments of the attentive state? It all depends upon the stage of development at which attention appears. At first, in =primary attention=, the organism _perceived_ the strong or sudden or novel or moving thing, as sight or sound or touch, and also _felt_ it, as disturbing or startling or surprising; attention implied a sense-feeling. At the same time, the organism _took up an attitude_ to the stimulus, in the literal sense; faced it, as peering and listening and frightened animals face such stimuli to-day. At this stage, then, _the shift of vividness is always accompanied both by feeling and by sensations_,—sensations due to internal bodily changes and to muscular attitude. Then comes =secondary attention=, with its conflict between various claimants for the inner circle of attention; and the conflicting stimuli will, naturally, arouse a medley of sense-feelings and set up a struggle of more or less incompatible motor attitudes. In civilised man, the scene of the conflict has been largely transferred from perception to idea; but _the effort that we make when we apply ourselves to a task, the difficulty that we have in settling down, the fatigue that results from sustained work upon a difficult theme_, all these things are reminders of the general uneasiness and restlessness that characterise secondary attention at the perceptive level. Only when we come to =derived primary attention= do feeling and kinæsthesis cease to be necessary factors in the attentive state. What we call mechanical, habitual, expert, professional attention means extremely vivid experience; but it _need not involve either feeling or kinæsthetic sensation_. Attention is no longer turbid with organic processes; the stream of mind has cleared itself. Common sense would say, and rightly, that a cool and critical poise has replaced the older animal excitement, and would emphasize the value of this change. We do not question the value; but we are at the end of our psychological enquiry when we have shown what the change in experience actually is, and how it is brought about.