The rapid dwindling of classes in the upper grades of U.S. grammar and high schools has been often noted, and many suggestions as to the improvement of the system of education have been emphasized by reference to this tendency. It is clear that after all that has been done, the attendance of pupils, particularly in the elementary schools, is still…

It should now be recognized that every child has at least five parallel ages: A "chronological" age, in years, months, and days: a "physiological" age, indicative of physical growth and maturity; a "mental" age, significant of intellectual capacity and ability; a "school standing," or "pedagogical"…