It is in place, therefore, to say clearly, at the outset, that this chapter does not mean to stimulate parents or unpsychological readers to report observations; and further to say also that in the mind of the writer the publications made lately of large numbers of replies to "syllabi" are for the most part worthless, because they heap together observations obtained by persons of every degree of competence and incompetence.
On the other hand, the requisites here, as in every other sphere of exact observation, are clear enough.

The student of the child's mind should have a thorough knowledge of the principles of general psychology, in order to know what is characteristic of the child when he sees it, and what is exceptional; and he should also have enough originality in his ideas and interpretations to catch the valuable in the child's doings, distinguishing it from the commonplace, and to plan situations and even experiments which will give him some control upon those actions of the child which seem to be worth it.

The need of these qualities is seen in the history of the problems of the child's growth which have been taken up even by the most competent psychologists.

The results show a gradual attainment of control over the problem in hand, each observer criticising the method and results of his predecessor until certain rules of observation and experiment have been evolved which allow of the repetition and repeated observation of the events of the child's life.
As illustrating the sort of problems in which there has been this careful and critical work, I may instance these: the child's reflex movements, the beginnings and growth of sensation, such as colour, the rise of discrimination and preference, the origin of right and left-handedness, the rise, mechanism, and meaning of imitation, the acquisition of speech and handwriting, the growth of the child's sense of personality and of his social consciousness, and the laws of physical growth, as bearing upon mental development.

In all these cases, however, there is again a greater and a less exactness.