490 W. R. BOYCE GIBSON : does not at a bound change its order, degree, or family ; it can only make one of these changes at once '. And he adds : ' The classical putrere did not turn at once into the French pourrir ; it passed in the Merovingian Latin into the forms putrirc, pudrire, and in Old French through the successive forms podrir and porrir, whence finally pourrir : the tr had to become the intermediate dr before it reached rr.' l Whitney gives the physiological reason for this when he points out that ' one sound passes into another that is physically akin to it, i.e., that is produced by the same organs, or otherwise in a somewhat similar manner.' 2 All this mutual adaptation and adjustment of sounds may with great truth be referred to a guiding principle of case or facilitation, provided (1) the principle is understood concretely, in which case the impulse to ease is no other than the im- pulse to the harmonious play of effort, the impulse towards pleasurable forms of activity ; and provided (2) the principle is not confused with the principle of economy. The im- pulse to ease with organic pleasure as its guide is doubtless the primary impulse whence the ideal of economy springs, but it is no more economy than unity of interest is unity of acquired meaning or skill. It is shortsighted and therefore often wasteful in its results. Thus, as Whitney points out, in such words as onijunnon, begun ; phuxian, to pluck ; etan, to eat ; the lost final syllables are those which showed the grammatical form of the words, being plural ending and infinitive ending. The impulse to ease in the performance of work finds ex- pression through that same cumulative process which we have seen to be so eminently characteristic of the continuity of mental growth. The reward of a difficulty overcome is, as we know, a greater ease in overcoming the next. There could be no facilitation, no easing of effort, were not the products of past achievements instrumental in, so to speak, pointing out to effort the way of ease. V. THE PRINCIPLE OF ECONOMY. We proceed now to a brief examination of that form of the Principle of Least Action usually known as the Principle of Economy, the principle of obtaining the maximum of result with the minimum of effort. 1 ( [f. Brachet, id., p. xcix. 2 Whitney's Origin of 7x/i</ ";/<', p. 58.
