2. The pubescent period is characterized by extensive range of all physical features of the individuals in it. Hence, although a period fit for great activity of the mass of children, it is also one of numerous individual exceptions to this general law. During this period a greater per cent of individuals than usual pass beyond the range of normal limits set by the mass. It is a time, therefore, when the weak fail and the able forge to the front, and hence calls for a higher degree than usual of individualization of educational work and influence. 3. Unidexterity is a normal condition. Rapid and marked accentuation of unidexterity is a pubescent change. On the whole, there is a direct relationship between the degree of unidexterity and the intellectual progress of the pupil. At any given age of school life bright or advanced pupils tend toward accentuated unidexterity, and dull or backward pupils tend toward ambidexterity.... Training in ambidexterity is training contrary to a law of child life. 4. Boys of school age at the Bridewell (reform school) are inferior in all physical measurements to boys in the ordinary schools, and this inferiority seems to increase with age. 5. Defects of sight and hearing are more numerous among the dull and backward pupils. These defects should be taken into consideration in the seating of pupils. Only by removing the defects can the best advancement be secured. 6. The number of eye and ear defects increases during the first years of school life. The causes of this increase should be investigated, and, as far as possible, removed. 7. There are certain parts of the school day when pupils, on the average, have a higher storage of energy than at other periods. These periods should be utilized for the highest forms of educational work. 8. The stature of boys is greater than that of girls up to the age of eleven, when the girls surpass the boys and remain greater in stature up to the age of fourteen. After fourteen, girls increase in stature very slowly and very slightly, while boys continue to increase rapidly until eighteen. 9. The weight of the girl surpasses that of the boy about a year later than her stature surpasses his, and she maintains her superiority in weight to a later period of time than she maintains her superiority in height. 10. In height, sitting, girls surpass boys at the same age as in stature, namely, eleven years, but they maintain their superiority in this measurement for one year longer than they do in stature, which indicates that the more rapid growth of the boy at this age is in the lower extremities rather than in the trunk.