Born on July 10th, 1860, the son of the Rev S Dyson, DD. He was educated at St Mary's Hospital, and in 1884 entered the Indian Medical Service, having attained a high place among the candidates at Netley, which entitled him to be nominated for the Bengal Army. He entered the service as a Surgeon on April 1st, 1885, was promoted to Surgeon Major on April 1st, 1897, and eventually rose to the rank of Lieutenant-Colonel on April 1st, 1905. He saw active service in the Burmese War of 1886-1888, having been posted to the 23rd Pioneers on his arrival in India. He at once became *persona grata* with the officers of the distinguished corps, and for his services in Burma was awarded the Medal with Clasp. Transferred to the Civil Department, he was appointed Deputy Sanitary Commissioner of the Punjab. His work here was distinguished by valuable researches on the pathology of hill diarrhoea. Dyson enlarged and amplified the old theory of the part played by mica in the causation of that affection, showing how it was present in the soil of those hill stations where the disease occurred, how it ceased when the water-supply was filtered before distribution, as exemplified at Darjeeling, and how it was non-existent in the stations where mica was not present in the soil. The admirable manner in which he performed his duties led to his being early selected for the important post of Sanitary Commissioner of Bengal. He now effected many needed reforms and continued his departmental researches, one set of experiments being upon direct vaccination from kids. His excellent Reports always received the commendation of the Government. On the expiration of his term in office in Bengal he was appointed to the onerous post of Superintendent of the large gaol of Hazaribagh. Latterly he was also Lecturer of Hygiene and Sanitation in the Medical College, Calcutta. At the time of his death he was Civil Surgeon at Saran. Dyson succumbed to the neglected attack of sprue - for he continued working too long for treatment to avail him. He died in Calcutta General Hospital on September 1st, 1907. He had been recently married, and was survived by his widow.