2. Disturbed sleep or sleeplessness may be due to causes purely
nervous. Such are bad habits acquired by faulty training; as when the
nursery is lighted and the child taken from its crib whenever it wakes
or cries; or when some of the contrivances for inducing sleep have
been used. Any excitement or romping play just before bedtime, and
fears aroused by pictures or stories, are frequent causes. Children
who inherit from their parents a nervous constitution are especially
likely to suffer thus.

3. There may be physical discomfort from cold feet, insufficient or
too much clothing, or want of fresh air in the sleeping room.

4. Interference with breathing due to obstruction from large tonsils
or adenoids. These cause great restlessness and lead a child to assume
many different postures during sleep, often lying upon the face or
upon the hands and knees.

5. Chronic pains or frequently recurring night pains may be causes of
disordered sleep, when a child wakes with a sudden sharp cry. In
infants this is most often due to scurvy, sometimes to syphilis. In
older children it may be the earliest symptom of disease of the hip or
spine.

6. Sleeplessness and disturbed sleep are frequent whenever the general
condition falls much below a healthy standard; e.g., in infants who
are not thriving and in children suffering from marked anæmia.

_How are children who sleep too little, or whose sleep is constantly
disturbed, to be treated?_