How is a milk mustache proof of good health? When it came to attending to families’ nutritional needs in the late nineteenth and early twentieth centuries, a swipe of creamy, white milk above an upper lip was a signal of medicine taken. In its earlier ship days, Floating Hospital doctors would write “prescriptions” for fresh milk to be taken onboard. Moms and children were happy to oblige, and the tell-tale milk mustache was a sign that they did as the doctor ordered.