Before baby is three months old, he should receive nourishment during the night at nine and twelve, and again at six in the morning. After four or five months a healthy child should not be fed between the hours of ten P. M. and six A. M. At this age, many children sleep right through from six P. M. to six A. M. without food. After five months, if a healthy baby awakens between ten P. M. and six A. M. warm water may be given from a bottle; he soon forgets about this and the night's sleep becomes unbroken. There are many other reasons than the need of food that cause the wakefulness of the child; and since the baby should, after a few months, sleep undisturbed and peacefully, if he is wakeful and restless--crying out in a peevish whine--and then quiets down for a few moments only to cry out again, you may suspect one of a half-dozen different things. Let us, therefore, summarize the things which may disturb baby's sleep: 1. _Lack of Fresh Air._ Babies cannot sleep peacefully in a hot, stuffy room, or in a room filled with the fumes of an oil lamp turned low. A crying fretful baby often quiets down as if by magic, providing he is not hungry and the diaper is dry, when taken into a cool room with fresh air. After the first two months the temperature of the sleeping room should be fairly cool and fresh. 2. _Clothes and Bedding._ The night clothes may be irritating and causing perspiration, while the bedding may be wrapped too snugly about the child. If baby's neck is warm and moist, you may know that he is too warm. If the diaper is wet it should be changed at once. One of the worst habits a baby can possibly get into is to become so accustomed to a wet diaper that it does not annoy him. In cold weather he is changed under the bed clothing without exposure or chilling. It may be the bedding is cold and, if so, it should be warmed up by the use of the photophore previously described, or by means of the flannel-covered hot water bottle. 3. _The Food._ Too little, too much, or the wrong kind of food, will disturb baby's sleep. Indigestion is very easily produced in babies who are improperly fed. For instance, the mother's milk may be lacking in nourishment and baby may really be hungry; or, as in the case of a bottle-fed baby, it is usually due to over feeding. Many mothers we have known who sleep with their babies or who sleep very near them, nurse them every time they wake up or murmur, and this soon becomes one of the biggest causes of disturbed sleep. 4. _Spoiling._ A lighted nursery or bedroom, rocking to sleep, jolting the carriage over a door sill or up and down, the habit of picking baby up the moment he cries, late rompings--any and all of these may disturb sleep, as well as unsettle the tender nervous system of the child, thus laying the foundation for future nervousness, neurasthenia, and possibly hysteria. This is particularly true in the case of the children who have nervous parents.