Interpreting and summarizing our experience with J. M.: Our system of individual instruction has permitted her to make full use of her intellectual ability. When we tried to depart from it to prevent her progress from becoming too rapid, she showed a lack of interest and in some parts of her school work she did not work up to capacity, and even became to a slight extent a discipline problem. Given, however, an incentive to first-class work and the training in social behavior which we are trying to give in our junior high school, J. M. developed successfully and well. On the whole, our system has enabled us to deal with her flexibly and as an individual. It has prevented us from prolonging our mistakes. Probably no system, or uniform plan, can be made to fit children of such exceptional mental endowments. The most we can hope for is a flexibility which will enable us to deal with such children as individuals, feeling our way as we go along. As for family background, J. M. originates from ancestors of very superior intelligence. Her parents were both tested by means of Army Alpha and both scored far above the generality of adults. Her father was educated as an electrical engineer but subsequently went into investment banking. J. M.'s paternal grandfather was an architect, trained in Manchester School of Science. He also attended the University of Edinburgh. The paternal great-grandfather was an architect and shipbuilder, expert in laying out factories, and he was descended from a line of builders. The paternal grandmother was an English woman, educated by her aunt, "who had advanced ideas on what a girl should study." The father of this grandmother was a dealer in building materials. On the maternal side, J. M.'s grandfather was first a teacher, then a merchant, who became very wealthy, and a mayor of a Southern town for eighteen years. The line of his descent was through Southern planters. The maternal grandmother was the daughter of a college professor, who in turn was the son of a physician and surgeon, coming from a long line of physicians. The mother of the maternal grandmother was descended from wealthy farmers. It is of some interest that for three generations at least, J. M. and her immediate progenitors were born when the parents were thirty years or older, in some cases being more than sixty years old.