The importance of maternal breast feeding is considerable for infant survival until weaning and beyond. In addition to nutrition, it also provides many of the mother’s immunological defenses to a baby whose own defenses are weak at birth. In the past, however, the protective (as well as the nutritive) qualities of maternal milk were unknown, and wet-nursing practices were common for social, cultural, and economic reasons. In the West, maternal breast feeding in the first year of life was most common in rural areas. But animal milks and solid food were given to babies everywhere when breast feeding was not possible, practical, or convenient, or when it was considered insufficient.

Maternal Breast Feeding

During the first year of life, mortality should be independent of the purely nutritional factor. It has been demonstrated that even undernourished mothers, subsisting on around 1,500 calories a day, are able to nourish their babies adequately through breast feeding (Livi-Bacci 1991). Nonetheless, in the past, infant mortality figures (which were usually high) varied enormously with maternal feeding practices. Babies not breast-fed are easily prone to gastrointestinal infections in summer and to respiratory infections in winter. Thus, environmental circumstances and child care were secondary factors of survival when compared with the manner in which infants were nourished.

Mother’s milk is in itself complete nourishment for a new infant. However, compared to the milk of a new mother (which comes in response to the direct demand of the suckling child), the milk of a wet nurse has neither the “age” nor the exact composition required for neonates, because usually the nurse has given birth to a child of her own some months earlier. Nevertheless, female milk is preferable to animal milk. Our ancestors were perfectly aware of the age of the milk – its color and consistency – when choosing a wet nurse. Yet before the 1750s, they did not fully appreciate the qualities of human milk and the superiority of a mother’s milk for her own child.