Infant Welfare Society poster, c. 1910s. Milk, considered a fundamental part of a healthy child's diet, could also be a killer. When left at room temperature, it offered germs a very agreeable environment. Armed with new knowledge about the transmission of the disease at the turn of the twentieth century, reformers set out to educate consumers on the virtues of keeping milk cool and protected.

Source: Chicago Historical Society (ICHi-37069)