James W. Winter qualified as a veterinarian (MRCVS) in London in December 1836. At some time during the next 14 years he served as veterinary surgeon to high ranking officials in Egypt. In 1846 he published a book entitled The horse in health and disease (London, 376p), which has been praised for the professional knowledge it contained. He emigrated to the Natal Colony in 1850 and by 1853 had settled in Pietermaritzburg as storekeeper and veterinary surgeon at 11 Church Street. He was one of the first veterinarians to make a living, at least part time, from private practice in southern Africa (see also J. Esterhuyse*, who practiced in Stellenbosch in 1847). By 1872 he was still listed as a merchant in Church Street, and in 1880 as a "gentleman" and property owner in Durban.
In 1873 Winter was appointed by the government of Natal to serve on its Redwater Commission. He was the only qualified veterinarian on the commission, the other two professional members being the medical practitioners P.C. Sutherland* and G.L. Bonnar*. The commission's report, published in the Natal Government Gazette in January 1874, inter alia recommended that the government should appoint official veterinarians to control animal diseases in the Colony. As a result S. Wiltshire* was appointed as the first state veterinarian in the colony later that year.
Winter appears to have been a versatile person with a variety of commercial and other interests. In addition to veterinary work he also served as a journalist for the Natal Witness during the 1870's. He owned a bottle store, as well as a sailing vessel, the Sea Nymph, with which he transported sugar to Madagascar and Australia. In 1877 he published an article on "The diamond fields of South Africa" in South African Notes, which was also published as a pamphlet (London, 1877, 13p). That same year he published a monograph entitled Gigantic inhumanity. South African notes on woman slavery, confederation, and the diamond and gold fields (London, 1877, 66p), in which he protested against the labola system in Natal. In the 1880's he marketed a product called "Winter's condition powder" which became well known in Natal. The railway station Winterskloof, just outside Pietermaritzburg, was named after him. He died at the age of 70 in 1886 and is buried in Pietermaritzburg.