
At the turn of the last century, many remained sceptical of both germ theory and preventative medicine. One public health official fought to change that – and saved thousands of lives.
The “suicide ward” is what New York City health inspectors called Manhattan’s Lower East Side at the turn of the 20th Century. With thousands of people packed into a single square mile, typhoid fever, measles, dysentery, and other contagious diseases found plenty of carriers. And in neglected tenement neighborhoods like this one, deficient sanitation and social services provided fertile breeding ground for disease-causing microorganisms.
The already poor conditions in tenement housing were made worse by the New York City Health Department’s neglect. In 1908, when Sara Josephine Baker became director of the department’s Bureau of Child Hygiene, the first of its kind in the country, she took a more hands-on approach. Turning her bureau’s attention to tenement neighbourhoods, she set up clean milk stations, dispatched trained nurses, and educated mothers in the science of germs and child hygiene.
At the time, infant mortality was startlingly, and embarrassingly, high for one of America’s most modern cities. In New York City alone, one-third of children died before the age of five, and on average, 1,500 infants died each summer. The numbers could have been even higher; when Baker began her job, she discovered that fellow inspectors were not reporting all sick infants, or inspecting all parts of the city.
By the end of Baker’s first year as director, infant mortality in the city fell by an estimated 1,200 deaths. Much of that was due to her focus on tenement neighbourhoods.
“She went into places where others wouldn’t,” says Elena Conis, historian of medicine and public health at University of California, Berkeley.

Over the course of her 30-year career in public health, Baker concentrated her efforts and resources on tenement neighbourhoods – expanding education programmes and training in childcare, creating foster programmes, and instituting welfare monitoring for children in schools and institutions. When she retired in the 1930s, press reports estimated that she prevented the death of 90,000 infants in New York City. No longer the “suicide ward”, the Lower East Side and the rest of New York City, by way of Baker’s public health programme, set a precedent that other cities across the country would quickly follow.
A New York native from Poughkeepsie, Baker chose medicine as a career not so much out of a conviction of its potential to do good, but as a way to earn money for her younger sister Mary and her mother. Her brother had died, followed by her father three months later.
No longer able to afford Vassar College, her first choice, Baker took a portion of what was left of the small family savings and enrolled at Women’s Medical College at the New York Infirmary, the all-women’s medical school founded by sisters and physicians Emily and Elizabeth Blackwell.
After graduating with her medical degree in 1898, Baker took a year-long internship at the New England Hospital for Women and Children in Boston. At 25, as Baker wrote in her 1939 autobiography, Fighting For Life, she still had a “still reasonably girlish soul”. But through working for the first time with the most impoverished people of a big urban city, she hurtled into adulthood. Delivering babies in people’s homes, she saw the living conditions of tenement housing – crowded, neglected, and unsanitary – that the poor and working class had no choice but to raise babies in.

When Baker returned to New York after her internship, she joined the New York Health Department as a part-time inspector in 1902.
Public health was still in its infancy. The New York City Health Department had only become a permanent body in 1886. But despite the department’s young age, when Baker joined, “New York was on the cutting edge of public health,” Conis says. Compared to when the department first launched, its officials now had the knowledge and tools of germ theory and bacteriology to fight contagious disease.
In the 19th Century, French chemist Louis Pasteur developed germ theory, which demonstrated that microorganisms and their multiplication caused decay and possibly disease. Building upon Pasteur’s work, German physician Robert Koch showed that specific microorganisms could indeed cause a corresponding disease when he identified the bacterium Bacillus anthracis as the cause of anthrax. Identification of other disease-causing microorganisms soon followed, including those that cause tuberculosis, cholera, typhoid fever, and plague. Instead of just treating symptoms, physicians now could prevent some forms of contagious disease.
Aided by these advances in medical science, Baker and her health department colleagues could test for bacteria, diagnose a disease, and vaccinate people.
But when Baker started her job, she found that some of her colleagues were not using the new tools at their disposal to their fullest extent.
Baker’s first assignment with the department was inspecting school children, a task she called in her autobiography “a pathetic farce”. She and her fellow inspectors were supposed to go to schools, examine any child that seemed ill and send them home. In one hour, she was expected to visit three schools – which did not allow much time for a medical diagnosis. Some inspectors, she said, did not even do this; rather, they called schools on the phone asking after the children, instead of going to inspect the schools themselves.
Baker could not stand the health department. “It reeked of negligence and stale tobacco and slacking,” she wrote, and its only accomplishment was to keep people on the payroll. “In honest moments, I could not help feeling that my own job was a minor racket too, for, even if I did work at it, I knew that I was accomplishing no good whatever.”
In her autobiography, Baker recalls a conversation with another inspector after one of their school visits. He asked her if she inspected tenements and reported the sick infants within. She said she did. “But if we don’t report any sick babies and you go ahead and report shoals of them, it makes our reports look pretty bad,” he said in response.
Baker’s colleague was right: that he wasn’t inspecting tenements, and reporting sick infants, did look bad. For their chief supervisor, it did not make sense that dysentery would tear through the tenement neighbourhoods reported by Baker, while others next door had no reported cases.

The other inspectors were ultimately dismissed. Baker was made the chief supervisor’s office assistant.
Of course, whether Baker’s detailed recollections of conversations recorded nearly 30 years later were verbatim seems unlikely. But today, Conis says that there is evidence that, at the time, officials and workers continued to be paid for jobs they did not complete.
Watching all of this changed Baker. “This spectacle of official negligence, or worse, was the last straw I think,” Baker wrote.
Where she initially lacked conviction to enter medicine, she now felt determined to stay in public health.
In 1907, Baker was promoted to assistant to the Commissioner of Health, and her personal interest increasingly turned to infant and child health.
Within a year, she had the opportunity to invest all her attention in children when she was appointed director of the Bureau of Child Hygiene, formed under the New York City Health Department. Created to tackle infant mortality, it was the first department of its kind in the US.
With this appointment, she became the first woman in the country to serve as an appointed health official of a major municipality.
Baker’s authority encompassed the entire city. But her area of focus was Hell’s Kitchen, a tenement neighborhood on the west side of Manhattan.

Hell’s Kitchen was marked by overcrowding, deficient sanitation and plumbing, and municipal neglect, all dusted with smoke-drift from factories. Most of the residents were European immigrants, new to the country and forced by economic and infrastructure constraints to live in tenement neighbourhoods. Many residents had no known precedent for how to thrive in the world’s largest modern city. The tenements and their residents were largely ignored or written off as hopeless cases.
But Baker took a different view. If mothers in tenement neighbourhoods were given more modern guidelines for how to care for children, she thought, then most infant and child fatalities could be prevented.
While it seems intuitive now, preventative medicine in public health was novel in Baker’s time, and so was the trial programme she spearheaded her first summer on the job. She dispatched nurses to individual homes to teach mothers about germs and how they spread (germ theory was not yet widely known outside of scientific circles); advised on breastfeeding to avoid bacteria-contaminated milk; taught to swaddle babies with cool, breathable clothing for summer; insisted on frequent bathing; and demonstrated proper ventilation of the home.

In addition to home visits, Baker set up baby health stations where mothers could find properly pasteurised milk, free of disease-causing bacteria, and nurses could weigh and perform wellness checks on infants.
To better serve mothers, she developed and dispensed an infant formula for those who could not breastfeed. She also successfully advocated for the licensing and regulation of midwives for pregnant mothers who did not feel comfortable with male physicians.
To aid mothers who worked outside the home, Baker formed the “Little Mother’s League”, which taught 12- to 16-year-old girls how to care for their infant siblings while their parents worked. Though the programme’s name implies these girls were being groomed for motherhood, they were receiving better public health education at the time than many medical students. Girls who enrolled progressed through 20 lessons, including on milk preparation, disease prevention, and observing a sick baby. They were given badges and prizes for meeting attendance. By 1915, 25,000 girls were enrolled.

Baker’s prevention and child hygiene programmes were unprecedented. But she also recognised that infants needed emotional care. In 1915, Baker stumbled into an unintentional experiment when a hospital for abandoned babies on Randall Island opened under the direction of the bureau. Despite receiving excellent medical care, nearly half of the infants at the hospital died.
Baker decided to try something new and sent the babies to be cared for by mothers on the Lower East Side. Receiving both affection and the best of Baker’s hygienic prevention, the death rate of the babies was cut in half.
With this experiment, writes historian Helen Epstein in the introduction to Baker’s autobiography, “Baker was the first to prove scientifically that [children] also need love.”
Contrary to accepted medical opinion that mothers should raise independent children or risk psychological damage, Baker found that no amount of scientifically crafted child care could make up for emotional neglect.
Baker wanted her efforts to reach further. Along with like-minded public health reformers and supportive members of Congress, she supported the Sheppard-Towner Act, a bill to create a nationwide programme that would provide federal funding for maternal and infant care, replicating some of the New York City programmes on a massive scale.
Among those who opposed the bill included the American Medical Association (AMA). When the bill was debated in Congress, a physician representing the AMA said: “We oppose this bill because, if you are going to save the lives of all these women and children at the public expense, what inducement will there be for young men to study medicine?”
As historian of medicine Regina Morantz-Sanchez explains in her book Sympathy and Science: Women Physicians in American Medicine, such arguments against the Sheppard-Towner Act were grounded in two things: a political ideology that viewed federal aid as “un-American” and a commitment to medical cures and treatment over prevention. With increasing focus on prevention rather than cure, there were fewer job opportunities for physicians trained in the latter.
Indeed, according to Elizabeth O’Hern in her book Profiles of Pioneer Women Scientists, some critics had a problem with Baker’s programme because of its very success. Fewer sick women and children meant less business for male physicians. “It was ruining medical practice by its results in keeping babies well,” read one petition, signed by a number of Brooklyn physicians, which asked the mayor to dissolve the bureau.
Baker was unmoved by such criticisms. “This is the first compliment I’ve received since the Bureau of Child Hygiene was established,” she quipped to the mayor in response. After all, the criticisms meant her programmes were working.

Throughout her autobiography, Baker takes on a similar light-hearted attitude in the face of both criticism and blatant sexism.
Still, the humiliation she later endured as a lecturer in public health at the New York University Medical School wore even on her pragmatic sensibilities.
In 1915, the university dean asked Baker to teach a course on child hygiene for the newly formed Doctor of Public Health degree. Baker declined because as a woman, she was not allowed to attend the course herself.
“I can hardly be accused of acting unreasonable because I declined to act as teacher in an institution that considered me unfit for instruction,” she wrote.
But when the dean could find no one else, he relented, letting Baker both teach the course and enroll in the program for a public health degree. The university then was forced to open its doors to other female students.
When Baker began to speak at the start of her first lecture, she was immediately interrupted by her male students as they broke into disruptive, thunderous clapping, stopping only once she laughed along with them to save face. At the end of the lecture, they resumed clapping, and she recalled that she fled the classroom, “frightened and tired… from talking a solid hour against a gloweringly hostile audience”. She described the clapping “not [as] the spontaneous burst of real applause that can sound so heart-warming, but instead the flat, contemptuous whacking rhythms with which the crowd at a baseball game walk an unpopular player from the outfield”.
For 15 years, every lecture she gave at the university opened and closed the same way.
When Baker was sent in 1907 to collect blood and urine samples from a cook named Mary Mallon, she was not expecting a fight.
Mallon was the first known asymptomatic carrier of typhoid fever, meaning she could carry and spread the disease-causing microorganism without ever becoming sick. Through the food she prepared, she unknowingly caused nine outbreaks, resulting in 53 typhoid cases and three deaths.

When Baker arrived at Mallon’s place of work, Mallon refused to hand over her bodily fluids to be tested for bacteria and fled. It took Baker and police officers two days to find Mallon and take her by force to a local hospital.
The hospital laboratory confirmed typhoid bacteria, and Mallon was quarantined in the custody of the Health Department for three years. She was released under the promise not to work with food again and given a job as a laundress.
As both a woman and an Irish immigrant, gainful employment for Mallon was limited, and she was paid far less cleaning laundry than cooking for upper-class families. She also never fully accepted germ theory, nor that it was possible that she could be spreading disease without ever being sick herself.
In 1915, Mallon returned to cooking. After another resulting typhoid outbreak, Baker tracked her down a second time. Mallon was quarantined by the state for the rest of her life on North Brother Island in New York City’s East River.
Baker said that she grew to like and respect Mallon. But she could not grasp Mallon’s unwillingness to accept the science of germs. “It was Mary’s tragedy that she could not trust us,” Baker said.

Mallon’s distrust of Baker was not an isolated incident: trust in public health was “unevenly distributed among communities”, Conis says. For instance, many immigrants came from countries where government-enforced vaccinations were unheard of. The power Baker wielded as a municipal authority was wholly unfamiliar.
Stereotypes about immigrant communities – including those to which Baker herself subscribed – further hampered trust in public health.
In her autobiography, Baker frequently refers to Irish immigrants en masse as “shiftless”, and says of the Irish in Hell’s Kitchen that they were “altogether charming in their abject helplessness, wholly lacking in any ambition and dirty to unbelievable degree”. In Baker’s view, the only other group who could match the Irish “distinction of living in the most squalor was Russian Jews”, who managed to survive “out of thrift”.
For communities so frequently maligned and stereotyped, trust was not easily given just because someone with Baker’s authority asked for it.
What Baker never seemed to understand about the immigrant communities she served was that when her advice was ignored, it often wasn’t a failure of understanding. Rather, it was that those, like Mallon, who she explained the science of germs to, had little control over their own lives and circumstances.
Even though Baker retired from the Bureau of Child Hygiene in 1923, her work extended beyond the health department. She was prolific writer, publishing hundreds of journal and newspaper articles on public health and five books on child health and hygiene for non-experts. She also founded the American Child Hygiene Association, of which she became president in 1917, and served as president of the Women’s Medical Association in 1935.
Baker spent the last years of her storied life on a farm in New Jersey with her partner, the novelist and screenwriter Ida Wylie, and their friend, physician Louise Pearce. She died of cancer in 1945.
While she went to greater lengths than any other public health official to learn the needs of tenement residents, Baker never seemed to quite understand why some greeted her and her municipal authority with scepticism. Nor did she reflect on the role she may have played in perpetuating that distrust.
Had she done so, it’s easy to imagine how many more lives she could have saved. As it is, however, she deserves a reputation as one of the earliest and most influential crusaders for preventative public health – and provides an example of not only what to do, but what not to do, when it comes to public health.
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There are, however, many individuals from diverse backgrounds who have shaped our understanding of life and the Universe, but whose stories have gone untold – until now. With our new BBC Future column, we are celebrating the “missed geniuses” who made the world what it is today.
Portrait of S. J. Baker by Emmanuel Lafont.