During the first period of childhood, up to five, six or seven, or more accurately, up to the point at which the permanent teeth begin to appear, every child may be said to be a thymus-dominated organism, because the thymus, holding the other endocrines in check, controls its life. That is why up to the third and fourth years at any rate, most children seem alike. Closer observation, however, reveals points of differentiation and signs of the coming potencies of the other hormones. During the second period, up to puberty, these marks of the deeper underlying forces of the personality make themselves more and more felt. The thymus, like a brake that is becoming worn out, continues to function in a progressively weaker fashion. Until with the arrival of the gonadal (ovaries' or testes') internal secretion, its influence is wiped out. There is a definite degree of thymus activity during everyone's childhood, unless by its premature involution, precocity displaces juvenility. Yet even during childhood, there are certain individuals with excessive thymus action, foreshadowing a continued thymus predominance throughout life. The "angel child" is the type: regularly proportioned and perfectly made, like a fine piece of sculpture, with delicately chiselled features, transparent skin changing color easily, long silky hair, with an exceptional grace of movement and an alertness of mind. They seem the embodiment of beauty, but somehow unfit for the coarse conflicts of life. In English literature several characters are recognizable as portraits of the type, notably Paul Dombey, whose nurse recognized that he was not for this world. They may look the picture of health, but they are more liable than any other children to be eliminated by tuberculosis, meningitis or even one of the common diseases of childhood. It is after puberty, when the thymus should shrink and pass out of the endocrine concert as a power, that the more complex reactions of personality emerge when the thymus persists and refuses to or cannot retire. The persistent thymus always then throws its shadow over the entire personality. To what extent that shadow spreads depends upon the strength of the other glands of internal secretion, their ability to compensate or to stay inhibited. Whether or not the pituitary will be able to enlarge in its bony cradle seems to be the most important factor determining these variations. If there is space for it to grow, at any rate normally, the individual may pass for normal, although he will have difficulties throughout life he may never understand, particularly in sexual directions. If the pituitary is limited. partially or completely, the thymus predominance is more prominent and fixed, and the abnormalities become obvious, both of person and conduct.