We have already drawn attention to the fact that mere sentience, if it exists, has no power of guidance over organic behaviour; but consciousness, when it emerges, is a concomitant of nervous processes which determine the nature and direction of such nerve-changes as are the antecedents of intelligent behaviour. The steps by which this control is established are unknown. It is, indeed, probable that conscious guidance arises as an accompaniment of the differentiation of controlling centres from the automatic centres of the nervous system; but of how this takes place we are as ignorant as we are of many other differentiations in the course of embryological development and evolutional progress. Of those nervous arrangements within the brain which are the physiological concomitants of the far later mental processes of reflection, abstraction, generalization, and the formation of ideals, we are, if it be possible, even yet more profoundly ignorant. Nor would it serve any good purpose to indulge in speculation where there are not even the data to enable us so much as to hazard a probable guess. The utmost we are justified in attempting is to show how organic behaviour leads up to and affords the requisite data for the exercise of intelligence, and how both supply the necessary preliminary stages in the development and evolution of what, following Dr. Stout, we have termed ideational process. This we have endeavoured to do in preceding pages; and all that is now required is to conclude our inquiry with a brief summary by which the results, as affording some basis for evolutional continuity, may be focussed.