becomes absorbed in some interesting occupation, the movements will
disappear for the time being.


AIR SWALLOWING, THIGH RUBBING, THUMB SUCKING

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