Dating from 1905 through 1916, this material consists of bound notebooks compiled by Oswaldo Cruz that hold carbon copies of telegrams and letters that he sent to Brazilian politicians and public health officials while he was at the helm of both the General Directorate of Public Health and the Oswaldo Cruz Institute. Of special note are the telegrams to President Rodrigues Alves (1902-1906) and to Minister of Internal Affairs J. J. Seabra, while Cruz was on expeditions to a number of Brazilian sea and river ports, from 1905 to 1906. When the Federal Serum Therapy Institute was renamed the Oswaldo Cruz Institute, Cruz also sent his personal thanks to President Afonso Pena (1906-1909). The telegrams include several written to public health officials to recommend that passengers be vaccinated, accompany shipments of vaccine lymph for smallpox, and order the inspection of baggage belonging to immigrants who were suspected of having diphtheria, along with other port sanitation measures. In 1913, Cruz wrote to Hélio Lobo, then Minister of Foreign Affairs, to inform him that he would be honored to receive former U.S. President Theodore Roosevelt for a visit to the institute. The last item is a telegram dated 1916, which Cruz sent the founders of the National Defense League (Pedro Lessa, Olavo Bilac, Miguel Calmon, and President Venceslau Braz), advising that he would be unable to attend the meeting at the National Library where the league would be installed, most likely for health reasons.