Samuel S. Dornan, Presbyterian missionary, was the eldest son of Dr William Dornan and his wife Margaret. He studied at Dublin University, graduating as Master of Arts (MA), and came to South Africa during the Anglo-Boer War (1899-1902). Afterwards he joined the Paris Evangelical Mission in Basutoland (now Lesotho), being stationed at the training institution at Morija. In addition to his missionary work he studied the customs and languages of the indigenous people with whom he came into contact. He was also skilled in mathematics and geology, and surveyed the geology of parts of the country for the government. In 1905 he became a member of the British Association for the Advancement of Science and at the joint meeting of the association with its South African counterpart, held in South Africa in 1905, presented a paper, "On the geology of Basutoland", which was included in the Addresses and papers... published after the meeting (Vol. 2, pp. 119-131). Subsequently he published "Notes on the ancient volcanoes of Basutoland" (1907) and "Notes on the geology of Basutoland" (1908) in the Geological Magazine. He was elected a Fellow of both the Geological Society of London and of the Royal Geographical Society.
In 1907 both Dornan and his wife became members of the Philosophical Society of the Orange River Colony. His interest in the local people and their culture was expressed in a paper before the society on "The bushmen of Basutoland" (Transactions, 1903-1907, Vol. 1, pp. 52-65). This was followed by a related paper, "Notes on the Bushmen of Basutoland", presented before the South African Philosophical Society, Cape Town, in November 1907 (Transactions, Vol. 18(4), pp. 437-). In 1908 he moved to Southern Rhodesia (now Zimbabwe), to help establish the native Presbyterian missions, and remained there for 15 years. That same year he joined the Rhodesia Scientific Association in Bulawayo, serving as vice-president for 1910/11 and as president for 1911/12. He presented three ethnological papers before the society, which were published in its Proceedings: "Some African burial customs" (1910, Vol. 9, pp. 88-127); "A remarkable resemblance between a Bantu and Bengali folk tale" (1911, Vol. 11, pp. 96-101); and "Some ethnological questions affecting Rhodesia" (Presidential address, 1912, Vol. 12, pp. 5-10). In 1911 he also joined the South African Association for the Advancement of Science, serving on its council from 1913 to 1920 and presenting the following papers: "The Masarwas and their language" (Report, 1911, pp. 218-225); "Rhodesian ruins and native tradition" (1915, pp. 502-516); "Some notes on Rhodesian native poisons" (1916, pp. 356-361); "Native ideas of cosmology" (1917, pp. 177-187); "Divination and divining bones (South African Journal of Science, 1923, Vol. 20, pp. 504-512); and "The crocodile in South African religion and folklore" (South African Journal of Science, 1934, Vol. 31, pp. 495-499). Other publications by him included an extensive paper on "The Tati Bushmen and their language" (Journal of the Royal Anthropological Society of Great Britain, 1917) and a book on Pygmies and Bushmen of the Kalahari: an account of the hunting tribes inhabiting the great arid plateau of the Kalahari Desert, their precarious manner of living, their habits, customs and beliefs, with some reference to Bushman art, both early and of recent date, and to the neighbouring African tribes... (London, 1925, 318p).
Suffering from health problems Dornan moved to Kimberley for a short period and in 1924 settled in the Transvaal, where he continued his missionary work and became superintendent of the native missions of the Presbyterian Church. He had an excellent knowledge of both Sotho and Tswana. According to his obituary his character was marked by honesty, modesty and charm, and he was a brilliant conversationalist. His first wife Jess, born Welch, died in 1920. He was survived by his second wife, Ellen A.M., born Moffat, but left no children. His personal papers, manuscrips and notes on anthropology are housed in the Strange collection of the Johannesburg Public Library.