Tracts in the child’s brain develop from undifferentiated nerve cells one after the other. All the essential phases of the ultimate life process are present to the young, so that the connections between the different brain tracts, which represent its different acts may be made and naturally will be made as fast as this is possible. The more we study the growth of the embryo and the infant, the more do we find that the relationship of environment to the developing form seems to be that of opportunity. The great advantage of intra-uterine growth seems to be that of the absence of the necessity of differentiating at an early stage,—the possibility of growing surrounded by the nutrient fluids of the adult parent form without the necessity of struggling for appropriate nourishment, and thus becoming fixed before its highest possibilities of growth were reached.