=B. Experiment.=--An experiment in any branch of science means the observation of results under controlled conditions. Experimental child study must, to a large extent, therefore, be relegated to the psychological laboratory. Such experiments as the localization of cutaneous impressions, the influence of certain operations on fatigue, or the discovery of the length of time necessary for a conscious reaction, can be successfully carried out only with more or less elaborate equipment and under favourable conditions. However, the school offers opportunity for some simple yet practical experiments in child study. The teacher may discover experimentally what is the most favourable period at which to place a certain subject on the school programme, whether, for instance, it is best to take mechanical arithmetic when the minds of the pupils are fresh or when they are weary, or whether the writing lesson had better be taught immediately after the strenuous play at recess or at a time when the muscles are rested. He may find out the response of the pupils to problems in arithmetic closely connected with their lives (for example, in a rural community problems relating to farm activities), as compared with their response to problems involving more or less remote ideas. He may discover to what extent concentration in securing neat exercises in one subject, composition for instance, affects the exercises in other subjects in which neatness has not been explicitly demanded. This latter experiment might throw some light upon the much debated question of formal discipline. In all these cases the teacher must be on his guard not to accept as universal principles what he has found to be true of a small group of pupils, until at least he has found his conclusions verified by other experimenters. =C. Direct Questions.=--This method involves the submission of questions to pupils of a particular age or grade, collecting and classifying their answers, and basing conclusions upon these. Much work in this direction has been done in recent years by certain educators, and much illuminating and more or less useful material has been collected. A good deal of light has been thrown upon the apperceptive material that children have possession of by noting their answers to such questions as: "Have you ever seen the stars? A robin? A pig? Where does milk come from? Where do potatoes come from?" etc., etc. The practical value of this method lies in the insight it gives into the interests of children, the kind of imagery they use, and the relationships they have set up among their ideas. Every teacher has been surprised at times at the absurd answers given by children. These absurdities are usually due to the teacher's taking for granted that the pupils have possession of certain old knowledge that is actually absent. The moral of such occurrences is that he should examine very carefully what "mind stuff" the pupils have for interpreting the new material.