What connection, if any, has moral instability to such physiological abnormalities as impacted teeth, irritating conditions of sexual organs, nasal occlusions, intestinal parasites and circulatory stagnations due to over-much sitting? What is the relation of mental and physical deficiency of children to alcoholism, syphilis, tuberculosis, or long continued dietary insufficiency during the period of growth?
What is the relation of oral hygiene to general health? What factors underlie the individual differences of children in predisposition to dental caries? How is this "disease of the people" related to nutrition, both as cause and effect? How is it related to school progress and morals? Is Osier justified in asserting that the problem of oral hygiene is of more consequence to racial welfare than is the alcohol problem?
What influence upon educational practise may we expect from the modern methods of roentgenographic determination of anatomic and physiological age differences? How large are such differences among children of the same chronological age? Does mental growth correlate with skeletal development, or with physiological age as determined by dentition and sexual maturity, or with chronological age, or with none of these? Current methods of promotion tend to a gradation by chronological age. Is it certain that this has more to commend it than a classification on the basis of height or weight? What percentage of school failures is due to subnormal physiological maturity? Should we always appeal to the roentgenograph to help decide doubtful cases of promotion? How frequently is nervous overstrain connected with a neglect of physiological age differences?
What are the physiological effects, ultimate, as well as immediate, of current methods in physical training? How are we to explain the surprisingly unfavorable showing of athletes in life-insurance statistics? Is it frequently justifiable to subject children to "corrective" gymnastic exercises in preference to free play? Just how, physiologically, does exercise which is enjoyed differ in its effects from exercise which is not enjoyed? Is the difference comparable to the difference found by Pawlow in the secretion of saliva and gastric juice under varying emotional conditions? What sports can safely be indulged in by children of different ages? Can any one state authoritatively what percentage of 16-year-old boys ought to attempt the five mile run? Might not research (research along these lines is now as rare as it is precious) teach us more reliable methods of diagnosticating athletic fitness and unfitness? (Professor Clark Hetherington is authority for the statement that not one physician in a thousand can make this determination.) What are the permissible limits of athletic specialization? What is the relation of muscular power to mortality and morbidity? Is current playground and gymnastic instruction sufficiently differentiated for age and sex differences? How far may physical training