Alexander Edington, bacteriologist, was educated at George Watson's College, Edinburgh, and the University of Edinburgh, obtaining the degrees Bachelor of Medicine (MB) and Master of Surgery (CM) in 1886. Having been a brilliant student he obtained several important academic appointments during the next four years, including that of assistant to the professor of surgery (1886), lecturer in bacteriology at the Edinburgh Medical School (1887-1890), and professor of comparative pathology at the New (Dick) Veterinary College (1889-1890). Furthermore, the University of Edinburgh awarded him the Syme surgical fellowship in 1889. During these years he was elected a Fellow of the Royal Society of Edinburgh and the Royal Botanic Society of Edinburgh, became a member of the British Medical Association and the Edinburgh Pathologists Club, and secretary of the Scottish Microscopical Society. He contributed a paper on "An investigation into the nature of scarlet fever" to the British Medical Journal in 1887, and another, "On a form of hyaline degeneration" to the same journal in 1891. Two other papers dealt with his bacteriological investigations of diseases in salmon, and were published in the Report of H.M. Scottish Fishery Board in 1888 and 1889. Two further bacteriological papers appeared in Scottish scientific journals in 1889 and 1891.
In February 1891 Edington was appointed as the first Government Bacteriologist of the Cape Colony, on a three year contract. He first visited the Pasteur Institute in Paris and Robert Koch* in Berlin to become familiar with the latest techniques and developments, and then went to Jena to purchase microscopes and other equipment. After reaching Cape Town early in June he and the colonial veterinary surgeon, D. Hutcheon*, went on a tour to select a site for a Colonial Bacteriological Institute. They chose a former depôt of the Royal Engineers in Grahamstown, where Edington was able to move into his laboratory in October to initiate organised bacteriological research in southern Africa. Meanwhile he was licensed to practice medicine at the Cape of Good Hope on 23 September 1891.
He started research on horse-sickness toward the end of January 1892, assisted by the veterinary surgeon J.D. Borthwick*, a former student of his from Edinburgh. In August that year he rashly announced that he had discovered the microbe causing the disease, creating the expectation that future epidemics would be prevented by the development of a suitable vaccine. This was but the first of several premature announcements of his progress in combatting the disease over the next 12 years. However, he did make significant contributions to its study, and to the investigation of heartwater, redwater, lung-sickness, and other stock diseases. In February to March 1893 he and Borthwick travelled to the Transvaal and then on to Natal, where they met Samuel Wiltshire*, in search of cases of horse-sickness that they could study. Meanwhile his inoculations against lung-sickness in cattle, using meticulously cleaned lymph from diseased animals, proved successful. During the same year, at the government's request, the work of the Institute was expanded to include the preparation of calf vaccine lymph for vaccination against smallpox. Supplies were provided to all the South African states.
In May 1893 Edington became the first editor of the (second) South African Medical Journal. In December that year he was appointed Acting Medical Officer of Health of the Colony, in addition to his directorship of the Colonial Bacteriological Institute. After spending some time in Cape Town in 1894 he left for England to study new developments in his field. He was succeeded as Medical Officer of Health by Dr. George Turner*. After his return early in 1895 he instituted a service of bacteriological diagnosis, soon expanded to include the general examination of tissues and exudations, which became popular among medical practitioners and public health officials. This service was made possible by the appointment of Dr. R.S. Black*, who worked mainly on human diseases. Edington meanwhile continued his investigations of stock diseases, particularly horse-sickness, assisted by W. Pye*. At this time he speculated that the organism causing the disease might be one of the filamentous fungi, and claimed to be able to prepare a vaccine against it. However, the animals he vaccinated did not prove to be immune.
Edington's research is documented in his Report of the Colonial Bacteriologist, later his Report of the Director of the Colonial Bacteriological Institute, for the years 1892 to 1904. In addition he published a number of papers in the Agricultural Journal of the Cape of Good Hope and other journals on his investigations of stock diseases and on the relations that he thought existed between them: "Redwater, Texas fever, or tick disease", a report to the Secretary of Agriculture, dealt with his development of a method of inoculation with the blood of salted animals, similar to the method developed in the US and Australia (Agricultural Journal, 1898, Vol. 12, pp. 690-703). In another report to the Secretary of Agriculture, "Heartwater", he indicated that his experiments with this disease had not yet led to conclusive results (1898, Vol. 12, pp. 748-760). He returned to it in a second paper two years later (Vol. 17, pp. 673-674). A major paper on "South African horse-sickness: Its pathology and methods of protective inoculation", first published in the Journal of Comparative Pathology and Therapeutics in 1900, was reprinted locally (Agricultural Journal, 1901, Vol. 18, pp. 142-155). His "Note on the co-relation of several diseases occurring among animals in South Africa" dealt with the similarities among heartwater, horse-sickness, and veld-sickness. The paper was read at the first annual meeting of the South African Association for the Advancement of Science in Cape Town (Report, 1903, pp. 260-275) and reprinted in the Agricultural Journal. At the same meeting he read another paper, "On the production of a malarial form of South African horse-sickness" (Report, 1903, pp. 276-281). He followed both these contributions up with articles in overseas journals. In these papers he propounded various theories on the etiology of horse-sickness, confounding it with equine piroplasmosis and with heartwater. None the less his work on this disease constituted his main contribution to science and brought him international recognition. He was awarded an honorary Doctor of Medicine (MD) degree by the University of Edinburgh in 1900.
In October 1896 Edington began his participation in the country-wide investigation of the dreaded rinderpest by setting up a temporary laboratory in a railway carriage at Taung in the Kalahari with the aim of develping a protective vaccine. He found that blood from diseased animals, if kept for several days, could be used to inoculate healthy animals, producing temporary immunity. Although this finding was encouraging, its utility was limited. Owing to the slowness of transport, sick animals would have to be kept fairly close to healthy ones and the disease would spread too fast to control. Following the development of bile inoculation by Dr R. Koch* in February 1897, Edington improved the method by inoculating with glycerinated bile, followed by increasing amounts of virulent blood ten days later. The resulting immunity was of uncertain duration, and his method was soon superceded by inoculation with serum. He participated in the debate about the disease and its control in the Agricultural Journal and the South African Medical Journal in 1897 and on 4 October that year attended a conference with D. Hutcheon, G. Turner, W. Kolle*, and the Secretary for Agriculture (P.H. Faure) to discuss the effectiveness of various methods of inoculation. The minutes were published in the Agricultural Journal (1897, Vol. 11, pp. 490-521). His article "A retrospect of the rinderpest campaign in South Africa" was published in The Lancet of 11 February 1899.
Edington joined the South African Philosophical Society in 1897. In 1902 he became a foundation member of the South African Association for the Advancement of Science, serving on its council during 1903/4 and 1904/5. His membership of both organisations ended in 1905. In 1904 he served on the council of the Eastern Province (Grahamstown) Branch of the British Medical Association.
Edington travelled extensively throughout South Africa on field work. He continued his work under trying conditions during the Anglo-Boer War (1899-1902), but in August 1901 left the Institute on sick leave for six months. In July 1902 he was sent to investigate an outbreak of trypanosomiasis among domestic animals in Mauritius, and later visited Zanzibar for the same purpose. He resigned his post in 1905 and returned to Scotland for further study, obtaining the Diploma in Tropical Medicine and Hygiene and the Diploma in Public Health in 1906. Upon his return to South Africa he opened a practice in Lydenburg, Transvaal. In 1909 he moved to Johannesburg, and in 1912 to Howick, Natal. During World War I (1914-1918) he served in the East Africa Campaign as a lieutenant-colonel in the South African Medical Corps, returning at the end of 1917 to become superintendent of Grey's Hospital in Pietermaritzburg. In 1919 he published "Some remarks on Spanish Influenza - its nature and aetiology" in The Lancet. He retired in 1922 and settled in Greytown, Natal, where he opened a practice and served as medical officer of health. The next year he wrote to Prof. J.J.R. Macleod in Toronto, Canada, in whose laboratory insulin had been discovered in November 1921, to enquire how he could obtain some of the drug for his diabetic patients.