Hamilton often performed her inspections with stealth because of the obvious danger, both from the toxins and the anger of the wartime culture she was calling to judgment. But she had powerful allies as well, including highly placed officials within the war effort. One of those who opened doors for her was Franklin Roosevelt, then a young assistant secretary of the Navy. In her memorable telling, “He listened carefully to my plea. Then he sent for an admiral, who came in resplendent in white and gold and blue, a gorgeous creature who made me feel like a drab peahen,” and secured permission for her work.

Hamilton explained that qualified male scientists rejected her field because it was “tainted with socialism or with feminine sentimentality for the poor.” Yet she was one of many notable women in this era whose sharp sense of power dynamics and moral hazards established new precedents for civic responsibility for public health. Her close colleague Florence Kelley was hard at work on what would become the Sheppard-Towner Maternity and Infancy Protection Act, the first federal allocation for health care. Among the thousands of female nurses on the front lines of the 1918-19 flu pandemic (which killed 50 million worldwide, 675,000 in the United States) were black nurses who fought racist barriers to their service. Their struggle resulted in the first 18 black nurses to serve in the Army Nurse Corps and provided a small turning point in the continuing movement for health equity.

In 1915, Hamilton and Addams came closer to the war than most Americans, when they joined a group of women meeting at The Hague to explore the possibility of peace. That goal was elusive, but they proceeded deep into Germany, Austria and Italy, meeting with journalists, statesmen and even Pope Benedict XV. After the United States entered the war in 1917, Hamilton focused on her work in the United States. But in the spring of 1919, they returned to observe the consequences of the continuing blockade: critical shortages of food, soap and medical supplies. Indignant, she wrote her sister Norah, “we are punishing tiny mites of girls and boys for the sins of statesmen.”

America’s farms had become a vital cog in the food diplomacy that played an important role in the war and the armistice that followed. A key player in that diplomacy was an ambitious Quaker from Iowa, Herbert Hoover. He had been a mining executive in London when the war broke out and took the lead in organizing relief, first for the Americans living in Europe and then more widely. Hoover was in touch with Addams and Hamilton when they made their trips and took care to describe food aid in humanitarian terms, even as he stayed close to statesmen who were willing to use it as a weapon. President Woodrow Wilson told Congress in January 1919, “Food relief is now the key to the whole European situation and to the solution of peace.” The following month, a commission led by Winston Churchill recommended maintaining the blockade against Germany, because “it would be inadvisable to remove the menace of starvation by a too sudden and abundant supply of foodstuffs.” As the commission argued, Germany was “still an enemy,” and starvation could be “a powerful lever for negotiation.”

The blockade was finally lifted in the summer, after Germany signed the Treaty of Versailles. But as Hamilton and Addams reported, the starvation continued, thanks to the collapse of North Sea fishing, the demobilization of tens of thousands of soldiers with no ability to feed themselves in a shattered economy and the devastation of the flu epidemic. They wrote about visiting “air cure” parks on the outskirts of Frankfurt where children were divided by gender and spent days naked outside. As Hamilton observed, “they must get sunshine in their bodies to make up in part for the lack of fats, so we could see plainly the little stick like legs, the swollen bellies, the ribs one could count, the shoulder blades sticking out like wings.” Their only meal was a soup of hot water with coarsely ground grains, chopped green leaves and a few drops of margarine.

They also took care to describe what the German people thought about their situation. Presciently, the pair argued that a policy of generous food distribution made sense for both humanitarian and strategic reasons. “What was to be gained by starving more children?” bewildered German parents asked them. In an article in The Survey magazine on Sept. 6, 1919, Addams and Hamilton expanded on this, pointing out the misimpression Americans had about the state of affairs in Germany and painting a different sort of picture of the German people for the American public:

Doctors, nurses, men and women who are working against tuberculosis, to keep babies alive, to keep children healthy, to prevent youthful crime and foster education, these people are past the point of bitterness. What they are facing is the shipwreck of a nation and they realize that if help does not come quickly and abundantly this generation in Germany is largely doomed to early death or a handicapped life.

With the advantage of hindsight, we now know that starvation was indeed a “powerful lever.” In speeches, Adolf Hitler frequently invoked his own experience with hunger during this time, and Nazi propaganda relied on the years of forced deprivation to paint the picture of a racialized conspiracy against the German nation, perpetrated by a global network connected to the Jewish people. A 1923 General State Commission report from Bavaria pointed out that many were attracted to join the army for food security and claimed that hunger was “not to be an underestimated factor in the entire Hitler movement.” Hamilton was not an absolute pacifist and supported the Allied effort in the Second World War, which grew so tragically from the first.

As Hamilton expected, her report was greeted with derision and criticism. She responded with renewed commitment — and found renewed support. In the fall of 1919, she became the first female faculty member at Harvard. The university had not been looking to hire a woman. But as a search committee looked for the world’s leading expert on industrial toxicology, it realized that it had no choice — the few experts who did exist were mostly women, Hamilton chief among them. As she later explained, “industrial medicine had become a much more important branch during the war years but it still had not attracted men, and I was really about the only candidate available.”