John [Frederick] Maberly (sometimes spelled Maberley) received a private education in London and then entered the medical school attached to Middlesex Hospital. He qualified initially as a licentiate of the Society of Apothecaries of London (LSA) in 1885, and three years later as a member of the Royal College of Surgeons (MRCS, England) and a licentiate of the Royal College of Physicians (LRCP, London). He married Maria Johanna Bam, with whom he had six children.
Soon after qualifying Maberly came to the Cape Colony, where he applied in 1888 (unsuccessfully it seems) for licenses to practice both medicine and dentistry. He stayed in Grahamstown for a while, and then moved to the South African Republic (Transvaal) where he was licensed to practice as "genees-, heel- en verloskundige" (physician, surgeon and accoucheur) in April 1889. In 1890 he was living in Germiston and subsequently also practiced in Pietersburg (now Polokwane). After five years in the Transvaal he moved to Bulawayo, Southern Rhodesia (now Zimbabwe), until the Matabele Rebellion broke out in 1896. After peace was restored he visited England and continental Europe. Returning to the Cape he was licensed to practice there in August 1897. Two years later he wrote to the government about erecting a station for the production of cow pox vaccine. He settled in Woodstock, Cape Town, where he and other ratepayers were involved in a court case against the Woodstock municipality during 1901-1905. For some time up to 1904 he served on the town council. Woodstock was incorporated into Cape Town in 1913 and he was still living in the city by 1931.
Maberly's main scientific interest was in pharmacology, particularly the use of new natural drugs. For many years he investigated plants of the family Geraniaceae, particularly the genus Monsonia and the tuberous-rooted species of Pelargonium. While residing in the Transvaal and Rhodesia he used a tincture prepared from Monsonia, based on a folk remedy, to treat dysentery and published a record of 100 cases in The Lancet of 6 and 13 February 1897. (In the same year botanist P. MacOwan* published Monsonia - the Cape remedy for dysentery as Pamphlet No. 7 of the Cape Department of Agriculture). Maberly's findings generated a good deal of interest and some firms put preparations on the market. However, these did not prove very effective and Maberly's subsequent trials seemed to indicate that the medicinal effect depends on the species, the time of year, and the condition of the plants. He found the preparation effective also to prevent bleeding and perforation of the intestines in typhoid fever, a finding confirmed by his friend Dr W. Darley-Hartley* during the Anglo-Boer War (1899-1902). Maberly described his work in "The therapeutics of the varieties of Monsonia" (South African Medical Record, 1904, Vol. 2, p. 84). The next year he discussed it, with a review of investigations of indigenous medicines by others, in a paper entitled "Drugs as used in South Africa", delivered at the joint meeting of the British and South African Associations for the Advancement of Science in 1905. A revised version, "South African pharmacology", was included in the Adresses and Papers... (Vol. 3, pp. 327-341) published after the meeting.
In 1909, in a paper confidently entitled "The cure of typhoid" (Transvaal Medical Journal, Vol. 4, pp. 175-181) Maberly reported further progress. An early problem associated with the use of tinctures of Monsonia biflora to treat typhoid fever during its early stages had been its constipating effect. In 1905, with the help of an analytical chemist he isolated the plant's curative components (of indefinite composition), calling it entericin. Since then he had tested it successfully in four cases. A few months later he reported in the same journal that he had used larger and more frequent doses of entericin in two more cases and that it had proved very effective in ending the disease. Some further fairly successfulr trials, carried out with the help of Dr R.P. Mackenzie, were reported in "Results of an investigation on the action of Monsonia in typhoid fever" (Ibid, 1909, Vol. 5, pp. 73-74) and Maberly followed this up with "The therapeutics of Monsonia in relation to typhoid fever" (Ibid, 1911, Vol. 7, pp. 2-9). In the latter paper he concluded that tinctures of both Monsonia ovata and Monsonia biflora were effective in releaving the symptoms of the disease and shortening its duration.
Maberly's other published work included a paper on "A case of tetanus treated with chloral hydrate" in the South African Medical Record (1905, Vol. 3, p. 92); "The rinderpest in South Africa" (The Lancet, 1898); and several medical papers in the latter journal between 1897 and 1929. He became a member of the South African Philosophical Society in 1902 and continued for some time as a member of its successor, the Royal Society of South Africa (established in 1908). He joined the British Association for the Advancement of Science in 1905, and for a while around that time was a member also of the South African Association for the Advancement of Science. During the nineteen-thirties he (or another John Maberly) published two books in London: Aggressive medicine (1935) and The health of the nation and deficiency diseases (1938).