There is no substitute for mother's milk.

The statement asserts the unique value of breastfeeding, implying that human milk is biologically and practically unmatched by alternatives. Read in a medical-public-health register, it functions as a categorical endorsement of nursing over artificial feeding, stressing that substitutes may approximate nutrition but cannot fully replicate the complex, living properties of breast milk (e.g., immunological protection, digestibility, and mother–infant bonding). As a maxim, it also reflects a broader early-20th-century tendency to frame infant-feeding advice in absolute terms to counter aggressive marketing and growing reliance on proprietary infant foods and bottle-feeding. Its force lies in its simplicity: it turns a medical recommendation into a memorable rule.