Neil Macvicar, medical practitioner and Presbyterian missionary, was the son of Reverend Peter Macvicar and his wife Barbara S. Bayne. He went to school until the age of fourteen and then entered an apprenticeship with a firm of lawyers in Peebles. Through self-study he qualified for entrance to the University of Edinburgh, where he studied medicine. During his final year he fell ill with small-pox and scarlet fever, but nevertheless graduated with first-class honours as Bachelor of Medicine (MB) and Master in Surgery (CM) in 1894. Upon volunteering for missionary work in Africa the Established Church of Scotland sent him as medical officer to the mission at Blantyre, Nyassaland (now Malawi). As a result of doctrinal differences he was not allowed to take part in religious teaching and after returning to Scotland on furlough in 1900 was dismissed in 1901. His experiences in Malawi enabled him to publish an article on "Snake poisoning in central Africa" in the Journal of Tropical Medicine (1902). Meanwhile he continued his studies at the University of Edinburgh, where he obtained the Diploma in Public Health in 1902. That same year he was admitted to the Royal College of Physicians and Surgeons of Edinburgh. At some time he was elected a Fellow of the Royal Institute of Public Health.
In 1902 the Free Church of Scotland appointed Macvicar as the first medical superintendent of Victoria Hospital at Lovedale, a Presbyterian mission near Alice in the Eastern Cape. He assumed duty in October that year and remained in his post until he retired in 1938. During this period he developed the hospital, initiated the training of African nurses, and started the South African (Native and Coloured) Health Society. This society published about a dozen Health Pamphlets (of which he wrote three) in Xhosa or English around 1909-1911. From 1914 until about 1940 he edited The Health Magazine, which was published in English, Xhosa and Sotho, and was distributed all over South Africa. He also wrote semi-popular articles on medical and educational matters in the Christian Express (to 1920) and later in South African Outlook. He compiled a Xhosa health reader (Lovedale, 1910), an Outline of anatomy and physiology for nurses (Lovedale, 1928), and an English-Xhosa dictionary for nurses (Lovedale, 1935, 1949). In 1908 he visited the Orange River Colony and the Transvaal Colony as a member of the executive board of the proposed Interstate Native College. The board's efforts led to the establishment of the South African Native College (later the University of Fort Hare) at Alice in 1916.
During his early years at Lovedale Macvicar gave special attention to tuberculosis in the indigenous population. He first wrote a paper on "The relation of altitude and dryness of atmosphere to the spread of consumption among the natives of South Africa" (South African Medical Record, 1906). In 1907 he was awarded the degree Doctor of Medicine (MD) by the University of Edinburgh for his thesis Tuberculosis among the South African natives. The thesis was published as a paper (in five parts) in the South African Medical Record (1908) and reprinted as a pamphlet (Cape Town, 1908, 48p). The next year he read a paper on "Tuberculosis among the coloured population of South Africa" before the South African Medical Congress held in Durban. This paper was also published in the South African Medical Record (1910). Many years later he discussed "Tuberculosis of bones and joints" in the South African Medical Journal (1935).
He conducted research also on scurvy, particularly among mine workers, finding that it was the result of a lack of fresh food in their diet. This work, which prompted changes in the diet of mine workers, was published in the South African Medical Record (1906, 1920) and the Journal of the Medical Association of South Africa (1931).
Macvicar was a member of the South African Association for the Advancement of Science for some time. At the association's annual congress held in Grahamstown in 1908 he delivered a paper on "Health teaching in schools with special reference to native schools".
In 1898 he married Jessie Samuels at Blantyre and they had a son and a daughter. She died at Lovedale in 1936. After his retirement in 1938 he settled in Johannesburg with his daughter, who was a surgeon, and her husband. His interest in the effect of food on health led to the publication several pamphlets: What to eat and why (1939, 65p), Food (1942, 14p), and The people's food: recent discoveries and their application in South Africa (1946, 32p). Other pamphlets and booklets by him were Side-lights upon superstition (1939), Africa tomorrow? (1947), and Western civilization and the Bantu (1947).
Macvicar devoted his life to the welfare, and particularly the public health, of the African population of South Africa. In recognition of his contributions the University of the Witwatersrand conferred upon him an honorary Doctor of Laws (LL D) degree in 1945. The Macvicar Tuberculosis Hospital at Lovedale was named after him in 1940.