Although the baby should not be handled unnecessarily nor tossed about and played with by friends and relatives, it is important that his muscular development be promoted by regular and carefully planned exercise. It is usually considered best for the baby to lie quiet and undisturbed in his crib most of the time during the first three or four weeks. Dr. Griffith begins the baby’s exercise about that time by having the nurse or mother take him in her arms on a pillow and carry him about for a few moments several times daily. After a week or two of this form of exercise the baby is carried in the arms without a pillow but with his head and back carefully supported as the nurse is doing in Fig. 57. The position of the baby’s body is changed by his being carried about in this way and the movement of the nurse or mother as she walks, causes a certain amount of motion of the baby’s muscles which constitutes a gentle exercise. The baby should be carried first on one arm and then on the other in order that both sides of his body may be equally exercised. This semi-passive form of exercise by means of being carried about is regarded by many doctors as almost indispensable to the baby’s welfare. There is a possibility that lack of this form of “mothering” is one reason why babies in institutions sometimes fail to progress as they should. Certainly, it is inadvisable for the baby to be allowed to lie for very long in one position. By the third or fourth month the baby sits up in his mother’s arms, as she carries him about, and he may be placed on the outside of his crib coverings for a little while every day, to kick and struggle at will. His skirts should be rolled up under his arms, or removed entirely, to leave his legs quite free, care being taken that the room is warm and that he has on stockings. [Illustration: FIG. 57.—Method of carrying baby to support his head and back. ] By about the sixth month he will usually begin to make an effort to creep, if turned over on his stomach and helped a little, and he may be propped up in the sitting position, in his crib, for a few moments every day. As he gives evidence of having enough energy to creep farther than the limits of his crib permit, he may be put into a creeping pen, or upon the floor under certain conditions. It must be remembered that the floor is likely to be cold, drafty and dusty. You should assure yourself, therefore, that the floor is warm and that all drafts are cut off, and then spread a clean sheet or quilt on the floor before the baby is put down to creep. When the sheet is taken up, be sure that it is folded with the upper surface inside in order that when it is again put down the baby will play on that side and not on the side that has been next the floor. A creeping pen or cariole or some such provision is often more satisfactory than the floor, consisting as it does of a railed-in platform raised about six or eight inches from the floor.