Lastly, the aim of following nature means to note the origin, the waxing, and waning, of preferences and interests. Capacities bud and bloom irregularly; there is no even four-abreast development. We must strike while the iron is hot. Especially precious are the first dawnings of power. More than we imagine, the ways in which the tendencies of early childhood are treated fix fundamental dispositions and condition the turn taken by powers that show themselves later. Educational concern with the early years of life--as distinct from inculcation of useful arts--dates almost entirely from the time of the emphasis by Pestalozzi and Froebel, following Rousseau, of natural principles of growth. The irregularity of growth and its significance is indicated in the following passage of a student of the growth of the nervous system. "While growth continues, things bodily and mental are lopsided, for growth is never general, but is accentuated now at one spot, now at another. The methods which shall recognize in the presence of these enormous differences of endowment the dynamic values of natural inequalities of growth, and utilize them, preferring irregularity to the rounding out gained by pruning will most closely follow that which takes place in the body and thus prove most effective." 1 Observation of natural tendencies is difficult under conditions of restraint. They show themselves most readily in a child's spontaneous sayings and doings,--that is, in those he engages in when not put at set tasks and when not aware of being under observation. It does not follow that these tendencies are all desirable because they are natural; but it does follow that since they are there, they are operative and must be taken account of. We must see to it that the desirable ones have an environment which keeps them active, and that their activity shall control the direction the others take and thereby induce the disuse of the latter because they lead to nothing. Many tendencies that trouble parents when they appear are likely to be transitory, and sometimes too much direct attention to them only fixes a child's attention upon them. At all events, adults too easily assume their own habits and wishes as standards, and regard all deviations of children's impulses as evils to be eliminated. That artificiality against which the conception of following nature is so largely a protest, is the outcome of attempts to force children directly into the mold of grown-up standards.