Generally the breasts are employed alternately, but both may be used at each nursing if one is insufficient. To fix the duration of the nursings arbitrarily is impossible; from ten to fifteen minutes generally proves satisfactory, but in each case systematic observations of the change in the baby's weight, of the character of its stools, and of its general condition must determine how long to leave it at the breast. The common error, unfortunately, is to be over-indulgent, and, as a result, infants are more frequently ill because the nursings are too long, than too short. Furthermore, the duration of the feedings can never be gauged accurately if the infant is allowed to nap while nursing. The successful training of a baby begins with the development of regular habits of nursing. The old-fashioned custom of allowing the baby to nurse whenever it cried, tacitly--and incorrectly--assumed that it could have no other sensation than hunger. As a matter of fact an infant may have pain from overfeeding. Again, it may be thirsty, or uncomfortable from the pricking of a pin, from the monotony of one position, from a soiled napkin, or from neglect of many simple details in its care. Any of these things make a baby cry, for it has no other means by which it can express disapproval. So long as the breasts contain colostrum the nursings should be at least three hours apart during the day; at night it is preferable not to disturb the mother at all. As soon as milk appears the interval is usually shortened to two hours during the day. In many cases, however, the three-hour interval will be retained even after the milk appears, for otherwise the infant may not become hungry and will fail to nurse as strongly as it should. The following schedule is adapted to the average infant: Age Interval During Total Number the Day of Feedings From 1st to 4th week 2 hours 9 " 4th " 8th " 2-1/2 " 8 " 2nd " 4th month 3 " 7 " 4th " 10th " 3 " 6 " 10th " 12th " 4 " 5 After the first few days most young infants require one feeding in the middle of the night, which is usually given about 2 A.M. The day feedings then begin at 6 A.M., and are repeated at regular intervals until 9 or 10 P.M. The daily bath should be scheduled so that a feeding will be due just after the bath has been completed. If asleep when the next succeeding feeding falls due, the infant should not be waked, but at other times nothing should interfere with the regularity of the schedule. Occasionally there may be difficulty in getting the child to nurse during the day, but it must be taught to do so; otherwise it will want to nurse throughout the night.