At a somewhat earlier age than that in which habit spasms become common, and before bed wetting appears as a formidable difficulty, we meet with another group of habitual actions which yet retain their voluntary character.  Among such habitual actions are thumb sucking, thigh rubbing, and air swallowing.  If the child is old enough to express himself on the subject, he will explain that these actions are performed because of the satisfaction derived from them, because it is “comfy” and “nice.”  Even if the child is too small to speak, the expression is that of beatitude and content.  These actions are not confined to nervous children, and their occasional practice need not be taken to imply that there is any strong element of nervous overstrain.  It is only when the action is repeated with great frequency and persistence, and when signs of irritation ensue if gratification is not obtained, that we are justified in classing it among the symptoms of mental unrest.

The second of these actions, thigh rubbing, is found for the most part in little girls, and inasmuch as it consists of a stimulation of the sexual organs sometimes causes much distress to the parents.  It is in reality a habit of small importance unless exercised with very great frequency.  It is, of course, not associated in the child’s mind with any sexual ideas, and is of precisely the same significance as the other two actions of the same class.  Children who can speak will refer to it openly without any sense of shame.  As a rule the action is performed in a half-dream state, that condition between sleeping and waking which is found when the child is lying in the morning in her cot or in her perambulator after the midday nap.  The child’s attention should not be focused on the symptom.  She should lie on a hard mattress, and when she wakes in the morning she should either leave her cot at once or she should be roused into complete wakefulness by encouraging her to play with her toys.  Little children should be taught to sleep with their hands folded and placed beside the cheek.  If the movement occurs on going to sleep, it is best left alone and completely neglected.  As a rule each child has his or her own favourite action of this class, and they are seldom combined in the same child.  If thigh rubbing is very constant and obstinate and does not yield to the measures suggested, it may even sometimes be a successful manoeuvre to substitute the thumb-sucking habit in the expectation that this less distressing habit may eject the other more objectionable action.  As a rule, however, a wise neglect and careful watching during the drowsy condition that follows sleep in a warm bed will succeed in stopping the practice of thigh rubbing before the end of the second or third year.  Apparatus designed to restrain movement of the child’s legs or blistering the opposed surfaces of the thighs are both of no effect.  They have indeed the positive disadvantage that they focus the child’s attention