The attitude of mind of a woman toward her milk supply is important, as the flow of milk is closely subject to mental influence. The presence of the child and the consequent exercise of maternal instinct does more to bring about the prompt, healthy flow of milk than anything else. Sometimes women in the later months of their first pregnancy upon seeing a mother nursing her child have felt the flow of milk to their breasts not rarely with such painful overdistention of the milk ducts as to require artificial relief. On the other hand, a fright may stop the flow of milk or make it scanty and a mother's aversion to a child may prevent her being able to nurse it. The sight of the father of the child in a state of intoxication may have a similar result.

How much milk supply may be dependent on the state of mind, or at least the state of the nervous system, can be realized from the animals from which we obtain milk. Any serious disturbance is likely to interfere with the milk supply. When a cow's calf is taken away the animal will often refuse for a time to give milk. If a cow is scared, as by the attack of a wild animal, or by being hit though only slightly injured by an engine, it will often not have milk for several days or even longer. There is an impression prevalent among farmers that if a cow takes a dislike to a particular person they are not likely to "give down" as much milk as would otherwise be the case. This may be only a curious farmer tradition, that has no basis in fact, although it is supported by so many observations reported from many different countries that it is apparently to be taken as of scientific value.

In modern times many fashionable women do not nurse their children because they have not the proper supply of milk. It is easy to see how this can be brought about through suggestion from many sources and the sight of others neglecting their duty in this matter. Most fashionable women would rather not nurse their children, and yet many of them feel a bounden duty in the matter. Some of these, however, having heard that many mothers of the better class are not capable of nursing their children, easily persuade themselves that they come in this category, and so their whole attitude of mind toward nursing is one of extreme doubt. Knowing as we do how the mental state influences nursing we are not surprised when these women prove not to have sufficient milk in the early days of the nursing. If they are to have it they must look forward with confidence to nursing their children and they must be ready and willing to take such food and secure such fresh air as will put them in the best possible condition for this function, always with the thought that nothing can be better for a child than to be nursed by its own mother. Nature has made exactly the form of food suited for the particular child, and it matters not how healthy a wet nurse may be, her milk is not likely to be so suitable. Much depends on the nutrition of the child during this early susceptible period of its life and there is more that passes over with the milk than merely the food elements. It is well recognized now that the reason why nurslings are protected from most of the so-called children's diseases and the contagious diseases generally, is that, as a rule, their mothers {461} have had these diseases, have acquired an immunity to them and this immunity is transferred to the child so long as the nursing process is continued. This has been shown to be true over and over again in animals and holds good for human beings.

Professor Von Leyden, the distinguished professor of medicine at the University of Berlin, points out that we are not quite sure as yet just what may happen to the human race from the very general refusal of mothers to nurse their children and the almost universal substitution of the bovine mother; whether in times to come certain bovine traits, at least as regards susceptibility to disease, may not be stamped upon the human race, cannot be determined until this experiment in ethnology, now being conducted on so large a scale, has been carried to some definite conclusion.

Perhaps this view is groundless, but there is no doubt that milk is more than merely a food and that during the period after birth when the child's nervous system is being formed, the perfectly adapted mother's milk is more likely to be the proper food than anything that human ingenuity can elaborate. We have heard much in recent years of the tendency of education and civilization to lower the birth-rate and to make women less fitted for maternity and for such maternal duties as nursing, but stronger than any deterioration of the physical constitution by the mental development is the unfortunate unfavorable effect of mental suggestion upon such functions, by which the preparation of the organism for their fulfillment is greatly influenced. It is in this respect that the women of to-day differ from the woman of the past much more than in mere physical development.