Happily, sulkiness, as an early symptom of chorea, or of other grave nervous and mental disorders, is of comparatively infrequent occurrence. The things the parents of a sulky child need more particularly to inquire into are the amount and character of the food the child eats, the state of his digestion, his habits of exercise, the ventilation of the rooms in which he spends most of his time, the condition of his nose, mouth, and teeth, and his ability to see and hear distinctly. But it must be admitted that any or all of these common physical causes of sulkiness may be present, and the afflicted child nevertheless contrive to get along without sulking. And, on the opposite, when a child thus afflicted does sulk, the correction of the physical trouble is not always followed by a cessation of the sulkiness. For, precisely as in the case of the child who remains mentally backward after the correction of bodily defects responsible for his backwardness, it may be that a habit of sulking has become established. What is much worse, it may also be that the sulky child has a home environment that makes sulking almost inevitable. Here we come to the central fact in the whole problem of sulkiness, for, nine cases out of ten, it is the home environment--the training a child receives, the parents' attitude towards him--that is primarily responsible for his sulking. The healthiest child in the world will sulk if his parents surround him with a sulk-breeding environment. He will sulk because _it is child nature to react appropriately to the suggestions received from the environment_. Every psychologist will bear out this statement. It also finds confirmation in the everyday experiences of all observant persons who have an opportunity to study children. It is all very well to exhort a child to be cheerful, to speak of "developing his will-power." But if the child's home surroundings are such as to fill his mind with depressing, disturbing ideas, he is bound to be influenced in his behaviour by these ideas. Parents are prone to forget this. They blame the sulky child when, in all justice, they ought to blame themselves. Recently a veteran New England school teacher, talking with me on this question of sulkiness, said: "There are times when I am tempted to believe that the home influence is _everything_, and that conditions of physical ill health have virtually nothing to do with sulkiness. Of course, I know that in reality physical conditions have to be taken into account, but my experiences with sulky children have been such that now, whenever I find a sulky child, I ask myself the question, 'What is wrong in that child's home?' If I have opportunity to investigate, I invariably find that something is wrong.