treatise on education. Besides this, his thoughts wandered confusedly round the notion of a treatise to be called Sensitive Morality, or the Materialism of the Sage, the object of which was to examine the influence of external agencies, such as light, darkness, sound, seasons, food, noise, silence, motion, rest, on our corporeal machine, and thus indirectly upon the soul also. By knowing these and acquiring the art of modifying them according to our individual needs, we should become surer of ourselves and fix a deeper constancy in our lives. An external system of treatment would thus be established, which would place and keep the soul in the condition most favourable to virtue.[258] Though the treatise was never completed, and the sketch never saw the light, we perceive at least that Rousseau would have made the means of access to character wide enough, and the material influences that impress it and produce its caprices, multitudinous enough, instead of limiting them with the medical specialist to one or two organs, and one or two of the conditions that affect them. Nor, on the other hand, do the words in which he sketches his project in the least justify the attribution to him of the doctrine of the absolute power of the physical constitution over the moral habits, whether that doctrine would be a credit or a discredit to his philosophical thoroughness of perception. No one denies the influence of external conditions on the moral habits, and Rousseau says no more than that he proposed to consider the extent and the modifiableness of this influence. It was not then deemed essential for a spiritualist thinker to ignore physical organisation.