Milk demystified by chemistry.

This article traces the decline of milk from a heavenly elixir to a tradeable food. Early cultures regarded milk not as a simple nutrient, but a living fluid. Heroes and gods were believed to have been nurtured by animals after being abandoned. Character traits were assumed to be transmitted by milk; infantile diseases were attributed to "bad milk", whereas "good milk" was used as a remedy. With chemical methods developed at the end of the 18th century, it became known that human milk was higher in sugar and lower in protein than cow's milk. During the 19th century, "scientific" feeding emerged that meant modifying cow's milk to imitate the proportion of nutrients in human milk. In Boston from 1893, Rotch initiated the "percentage" method, requiring a physician's prescription. In Paris from 1894, Budin sterilized bottled infant milk. In Berlin in 1898, Rubner measured oxygen and energy uptake by calorimetry, prompting feeding by calories, and Czerny introduced regulated feeding by the clock. These activities ignored the emotional dimension of infant nutrition and the anti-infective properties of human milk. They may have also enhanced the decline in breastfeeding, which reached an all-time low in 1971. Milk's demystification made artificial nutrition safer, but paved the way for commercially produced infant formula.