The age at which children are able to sit alone, stand and walk, varies greatly. Some infants walk as early as the tenth month, while others are as late as the eighteenth month. The average age at which children are able to walk alone is from thirteen to fifteen months. Other things being equal, the age at which a child walks has little significance. The first voluntarily directed movements of the child occur at about four months of age, sometimes a little earlier, when the child begins to make an effort to grasp objects which he sees about him. At about four or five months of age the average child is able to hold the head erect when the body is properly supported. Between the seventh and eighth month the muscles have developed sufficiently for the child to sit erect by himself for a few minutes at a time. From this on, the child develops the sense of equilibrium very rapidly. Not later than nine months of age the child will indicate a tendency to stand and to bear the weight upon the feet. He may even be able to stand with a little assistance; then, in a very short time, if placed upon the floor he will show a tendency to pull himself up by a chair and stand alone. This is soon followed by the first steps and by the thirteenth month the child is walking alone freely. Mechanical devices intended to assist the child in learning to walk are of little value and may be an actual detriment. If the child is normal, has the proper care and a reasonable environment, Nature will put him on his feet at the earliest possible moment without injury to the delicate structures of the body. If the child is extremely backward in learning to walk a careful analysis should be made to determine the reason. Rickets is a very common cause for backwardness in children, not only in walking but in other functions as well. If a child is backward in learning to walk he should not be urged, but the reason for this backwardness should be sought out and the cause adjusted. CHAPTER II DENTITION CHAPTER II DENTITION