The intercourse of adults yields, for the reason assigned, relatively few cases that fall completely within the same category. In their transactions from hour to hour, more or less of deduction from pure gratification is caused on one or other side by imperfect fitness to the requirements. The pleasures men gain by laboring in their vocations and receiving in one form or other returns for their services usually have the drawback that the laborers are in a considerable degree displeasurable. Cases, however, do occur where the energies are so abundant that inaction is irksome; and where the daily work, not too great in duration, is of a kind appropriate to the nature; and where, as a consequence, pleasure rather than pain is a concomitant. When services yielded by such a one are paid for by another similarly adapted to his occupation, the entire transaction is of the kind we are here considering: exchange under agreement between two so constituted becomes a means of pleasure to both, with no set-off of pain. Bearing in mind the form of nature which social discipline is producing, as shown in the contrast between savage and civilized, the implication is that ultimately men's activities at large will assume this character. Remembering that in the course of organic evolution, the means to enjoyment themselves eventually become sources of enjoyment; and that there is no form of action which may not through the development of appropriate structures become pleasurable; the inference must be that industrial activities, carried on through voluntary co-operation, will in time acquire the character of absolute rightness as here conceived. Already, indeed, something like such a state has been reached among certain of those who minister to our æsthetic gratifications. The artist of genius--poet, painter, or musician--is one who obtains the means of living by acts that are directly pleasurable to him, while they yield, immediately or remotely, pleasures to others.