Born at Manchester, the son of the Rev James Chalmers, MA. He was educated at the Manchester Grammar School, then at the Liverpool and University of London Colleges and Hospitals. After obtaining various exhibitions and medals in the earlier subjects, he gained honours in medicine and surgery at the MB in 1890; he obtained the Gold Medal at the MD of the Victoria University in 1893 with a Thesis, "Development of the Liver and Septum Transversum". He also held the following posts: Holt Tutorial Scholar; Demonstrator of Anatomy, Owens College; House Surgeon, Cancer Hospital, London; Assistant Medical Officer, Willson Green Asylum, Birmingham; Surgical Tutor and Pathologist, Royal Southern Hospital, Liverpool. After becoming FRCS in 1895, he joined the West African Medical Service and served on the Gold Coast from 1897-1901. In the Ashanti War of 1900 he was one of the garrison that fought its way out of Coomassie; he was mentioned in despatches and received the medal and clasp. In 1901 he was appointed Registrar of the Ceylon Medical College at Colombo, where during the following ten years he improved the organization and raised the standard of teaching, meanwhile lecturing on pathology and animal parasitology. In 1910 he joined Dr Aldo Castellani as joint-editor of their *Manual of Tropical Medicine* (the 3rd edition of 2500 pages was published in 1919), a standard text-book of permanent value. He served as Major in the Ceylon Medical Corps, and was a member of the Ceylon Coronation Contingent in 1911, for which he received the Coronation Medal. After resigning the appointment he travelled, and studied pellagra in conjunction with Dr Sambon, and he was one of the first to recognize the occasional occurrence of the disease in this country. In 1913 he became Director of the Wellcome Tropical Research Laboratory at Khartoum, and was the author, wholly or in part, of a series of publications on tropical disease. At the same time he was a member of the Central Sanitary Board of the Sudan, of the Sleeping Sickness Commission, and of the Archaeological Committee. During a holiday round the world he was including the study of tropical disease, when he was seized at Calcutta with acute infective jaundice, and died after a week's illness in the General Hospital on April 5th, 1920. He married the daughter of Edwin Cannington, JP, but there were no children. Chalmers collected some 1800 volumes, consisting partly of rare old books, including a 1478 Celsus, and partly of books on tropical medicine. The library was presented by his widow in June, 1922, to the Royal Society of Medicine. The books were arranged in a special room, named the Chalmers Library, and supplied with a special catalogue. The catalogue includes the numerous publications made by him, or in collaboration with others.