Sara Josephine Baker (November 15, 1873 – February 22, 1945) was an American physician notable for making contributions to public health, especially in the immigrant communities of New York City.

[1] In 1917, she noted that babies born in the United States faced a higher mortality rate than soldiers fighting in World War I, drawing a great deal of attention to her cause.

Preventative medicine had hardly been born yet and had no promotion in public health work.After working diligently in the school system, Baker was offered an opportunity to help lower the mortality rate in Hell's Kitchen.

[3] Baker and a group of nurses started to train mothers in how to care for their babies: how to clothe infants to keep them from getting too hot, how to feed them a good diet, how to keep them from suffocating in their sleep, and how to keep them clean.

Before Baker arrived, the bottles in which the silver nitrate was kept would often become unsanitary or would contain doses that were so highly concentrated that they would do more harm than good.

Baker designed and used small containers made out of antibiotic beeswax that each held a single dose of silver nitrate, so the medication would stay at a known level of concentration and could not be contaminated.

[15] While Baker was campaigning to license midwives, treat blindness, encourage breastfeeding, provide safe pasteurized milk, and educate mothers, older children were still getting sick and malnourished.

Mallon was the first known healthy carrier of typhoid, who instigated several separate outbreaks of the disease and is known to have infected more than 50 people through her job as a cook.

[17] Mallon was not the only repeat offender nor the only typhoid-contagious cook in New York City at the time, but she was unique in that she did not suffer any ill-effects of the disease and in that she was ultimately the only patient placed in isolation for the rest of her life.

[18] Josephine Baker was becoming famous, so much so that New York University Medical School asked her to lecture there on children's health, or "child hygiene", as it was known at the time.

[19] Baker spent much of the later part of her life with Ida Alexa Ross Wylie, a novelist, essayist, and Hollywood scriptwriter from Australia who identified as a "woman-oriented woman".

She became the president of the American Medical Women's Association and wrote four books, an autobiography, and 250 articles across the professional and popular press.