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Letter from Cruz to his son Bento, sharing news about the family’s life in London. He tells that he had a postcard photo taken with Miloca to serve as a model for a painting by Angelina Agostini and that he had been to the National Gallery in the company of Graça Aranha, then a diplomat there. He also reports on a German defeat and expresses optimism about how the war is going. Lastly, he goes into detail about the precautions the British are taking to prevent air strikes by German zeppelins. London, Sep. 15, 1914. Access the full version

On June 15, 1914, Oswaldo Cruz and his family set sail for Europe to visit some of the continent’s most preeminent centers of research. Paris was to be the first stop on the trip, but World War I broke out in late July, thwarting the plan. With Paris under heavy bombing, Cruz switched their destination to London, where he thought his family would run fewer risks. There, while he prepared his return to Brazil, he set up an apartment for his wife and children.

In January 1915, Cruz returned to Rio alone. From the age of 35 on, he had suffered from nephritis, the disease that had killed his father. Now, at the age of 42, his health was failing. Nevertheless, he resumed his post as director of the Oswaldo Cruz Institute with the same enthusiasm as ever. Shortly after Cruz’s arrival, the governor of Rio de Janeiro, Nilo Peçanha, asked him to draw up a plan to eradicate the sauva ant, which was decimating the state’s agricultural crops and causing serious harm to the state economy. Although Cruz was at first rather surprised by the invitation, he eventually accepted it.

His first idea was to kill the insects using a poison gas. But when he realized this might damage crops, he had an artificial formicary built so he could observe the ant’s habits. Then he devised a bolder plan: he would inoculate some specimens of the insect with highly virulent germs and then put them in contact with uncontaminated ants. The contagion was meant to prompt a violent epidemic that would exterminate the formicary’s entire population.

Cruz was never able to carry out the experiment, however. His disease was relentless. When his wife and children learned what was happening, they rushed back to Brazil. Cruz decided to take a leave from the Oswaldo Cruz Institute and move to Petropolis. It was 1916 and the municipality had just been incorporated. Nilo Peçanha appointed Cruz the first mayor of the city. It was a political position but would certainly be less demanding than managing the institute. It was also a way to let Cruz stay active.

Cruz was sworn into office on August 18. He threw himself into the job and drew up a bold plan for his administration. In addition to organizing sanitary services, his project called for audacious initiatives in education and transportation. Even the city’s river banks were not forgotten; gardening was one of Cruz’s passions and he planned to cover them with flowers.

Sadly, his stay in office was a brief one. With his illness progressing to its final stages, Cruz resigned as mayor on January 31, 1917. On February 11, he died at home, at the age of 44. It would not be long before the man became a legend.