Habit spasms or "tics" are common in childhood, and are caused by an over irritability of the nerves supplying certain groups of muscles. It is not at all uncommon to see a child nervously blink the eyes, twitch the nasal muscles, shrug the shoulders, constantly open and close the hand, and execute a score of other minor habit-spasms; which, day by day, wear deeper and deeper paths into his nervous system as a result of their constant repetition. These minor habit-spasms of childhood are but telltales of an unstable nervous system, of a nervous heredity lacking poise and balance; and, mind you, if this nervous system is studied, treated, and properly harnessed with self-understanding and self-control, much may be accomplished; the habit may be more or less completely eradicated. If left to itself, unchecked, the habit deepens the "spasm-groove," and the "energy-leaks" grow bigger and bigger until finally, in later, adult life, all that is necessary to convert such persons into first-class neurasthenics or hysterics is some bad news, a few worries, or a sudden shock. By all means study to nip all childhood twitchings in the bud; remembering all the while that childhood--the formative period for the nervous system of the child--presents the golden opportunity to prevent and abort the more grave neuroses of later life. There may be a special contraction of one or more muscles of the eyeball which produces either a "cross-eye," when the contraction is convergent, or a turning of one eye outward when the contraction is divergent. It is not possible for the mother to correct this condition. The one important thing for her to do is to take the child to a skilled ophthalmologist early in his life, that treatment may be instituted for the correction of the difficulty. RETENTION OF URINE Not an unusual condition during childhood is a temporary retention of urine. It may follow an attack of colic or accompany any acute illness. Increase the water drinking, and, after seven or eight hours, hot cloths should be applied over the bladder; a large enema (enema bag should be hung low) should also be given, retaining as much as is possible. These simple measures usually relieve the condition. If retention follows circumcision, due to swelling of the parts, the surgeon should be notified. BED WETTING Nocturnal enuresis (bed wetting) usually is found to "run in families." It is seldom the case to find that both the father and the mother escaped bed wetting during childhood when the child is sorely afflicted.