More common, and therefore much more important, are cases in which, because the mother allows herself day after day to worry over one thing or another, the secretion of milk suffers permanent disturbance in quantity or in quality. Sometimes worrying lest the milk will be unsatisfactory causes it to become so. Generally, however, unnecessary anxiety for the baby is to blame. Again and again, when there is really nothing out of the way, inexperienced mothers make themselves miserable because they fear something may go wrong. Such a state of mind always invites trouble; not infrequently it is the direct cause of insufficient or unwholesome milk. The self-assurance gained through taking care of the first baby is responsible more than anything else for the greater success mothers have in nursing subsequent children. The mother who is nursing her first baby should take success for granted, and never mistrust her ability to succeed. If the physician has been asked to visit the baby regularly, as was suggested at the beginning of this chapter, he will quickly detect the evidence of failure should failure be imminent. His opinions should be accepted and his directions followed, for by so doing the mother will most readily acquire the assurance which is so necessary to success. The habit, easily fallen into, of paying attention to promiscuous advice is unwholesome, for such advice is injudiciously given and is usually incorrect. More often than not the counsel of well-meaning friends only serves to perplex and distress the mother. _Recreation and Rest_.--Next to worry no influence upon lactation is more detrimental than neglect of recreation and rest. Both are very necessary to a nursing mother, for without them she will soon begin to exaggerate minor troubles and even to worry though nothing is wrong. A mother who has the care of a baby added to other responsibilities may have extraordinary difficulty in finding time for outdoor exercise, for congenial companionship, or for diversion of any kind. Occasionally it may seem almost impossible even to get time for sleep, a necessity so fundamental to health that, as we should expect, a mother deprived of it would fail utterly in nursing her infant. Difficult as it may seem, however, the mother must find time for recreation, for if she does not there will follow disturbances, generally in the quantity, or sometimes in the quality, of her milk. Keeping in mind that whatever benefits the mother will react favorably upon the infant, one should regulate exercise during lactation with regard to the kind and the amount of exercise to which she has been previously accustomed. Walking usually fulfils all the requirements satisfactorily, and there is ordinarily no reason why nursing mothers should not participate in sports that are unattended by violent exertion. Exhausting sports, however, must be shunned, because fatigue has the same injurious effect upon the secretion of milk as lack of exercise.