It is right that parents should realise that the disturbing and irritating element in the child’s environment is nearly always provided by the intrusion of the adult mind and its contact with the child’s.  Some supervision and some intrusion, therefore, is of course absolutely necessary, but the best-regulated nursery is that in which it is least evident.  Something is definitely wrong if a child of two years will not play for half an hour at a time happily and busily in a room by himself.  It is an even better test if the child will play amicably by himself with nurse or mother in the room, without the two parties crossing swords on a single occasion, without reproof or repression on the one side or undue attempts to attract attention on the other.  If the child is entirely dependent upon the participation of grown-up persons in his pursuits, then not only do those pursuits lose much of their educative force, but they become a positive source of danger because of the constant interplay of personality with personality.  The child who, seated on the ground, will play with his toys by himself, rises with a brain that is stimulated but not exhausted.  Only very rarely do we find that solitary play, or play between children, is too exciting.  In older children of very quick intelligence and nervous temperament we occasionally find that the pace which they themselves set is too exciting or exhausting.  I recall a little boy of seven, an only child of particularly wise and thoughtful parents, who was brought to me with the complaint that he exhausted himself utterly both in body and mind by the intense nervous energy which he threw into his pursuits.  For instance, he had been interested in the maps illustrating the various fronts in the European War, with which the walls of his father’s study were hung, and although left entirely by himself he had become intensely excited and exhausted by the eagerness with which he had spent a whole morning, with a wealth of imaginative force, in drawing a map of the garden of his house and converting it into the likeness of a war map, filled with imaginary Army Corps.  Such excessive expenditure of nervous force is unusual even in older children, and as in this case is found usually only when there is a pronounced nervous inheritance.  In little children in the nursery, solitary play or play between themselves seldom produces nervous exhaustion.  It is quite otherwise when the child is dependent to a too great extent upon the participation of adults.  It is almost impossible for the mother and nurse not to take the leading part in the exchange of ideas, and no matter what may be their good intentions, the pace set is apt to be too great.  Environment, without the intrusion of the adult mind, is best able to adjust the necessary stimulus and produce development without exhaustion.  Play with grown-up persons, the reading aloud of story books, the showing of pictures, and so forth, undoubtedly have their own importance, but