Macculloch , John , 1773-1835 , surgeon and geologist 

John MacCulloch was born in his grandparents' house in Guernsey on 6 October 1773. The third of eight children of James MacCulloch, a wine merchant, and Elizabeth de Lisle, the young MacCulloch was sent to schools in Cornwall between 1778-1790, before enrolling as a medical student at Edinburgh University in 1790. Whilst there he also read chemistry under Joseph Black and natural history under John Walker. MacCulloch graduated with an MD in 1793, but the following year his postgraduate studies were cut short by his parents' internment during the French Revolution.

MacCulloch became a surgeon's mate in the Royal Artillery on 15 August 1795, and by 1803 had risen to assistant surgeon. He was then drafted into the ordnance chemical department, becoming ordnance chemist in 1806 and retiring from the army with a small pension. He received his licentiate of the Royal College of Physicians in 1808, and set up a private medical practice in Blackheath, south east London but had to give it up when ordnance duties demanded prolonged absences for geological surveys. He still, however, managed to be appointed physician to Prince Leopold, later king of the Belgians, in 1820. MacCulloch's main contribution to the field of medicine was his writings on fever, notably his work on malaria in the late 1820s.

MacCulloch's burgeoning interest in geology can be traced back at least to the early 1800s, notably on his tours of the Lake District (1805) and the west country (1807), when he visited mines and noted down comments on local rocks in his diary. He was elected a Member of the Geological Society on 5 February 1808, and his paper on the geology of the Channel Islands, opened the first issue of the Society's 'Transactions' in 1811.

In his search for silica-free limestone for millwheels, MacCulloch conducted geological surveys in Wessex, Wales, and Scotland, between 1809-1813, and then from 1814-1821 acted as geologist to the ordnance trigonometrical survey during which he had surveyed hundreds of Scottish peaks and produced a geological map of west Scotland. However this intense survey work affected his health, and in 1821 he developed an enlargement of the spleen. Although he returned to work in 1822, his consitution remained affected thereafter.

Between 1816-1820, MacCulloch served as president of the Geological Society and in 1820 he was elected Fellow of the Royal Society. When in 1824, the chemical department of the ordnance was abolished, the now retired MacCulloch instead spent his summer field seasons surveying Scotland for the geological survey. Essentially MacCulloch became the first government sponsored geological surveyor in Britain, a move which was controversial as it cost the Treasury over £1000 per annum. Despite suffering a stroke in 1831, MacCulloch still managed to draft the final reports and map before his death four years later, his geological map Scotland being issued posthumously in 1836. Although criticised for topographical and geological inaccuracies, the map was not superseded for many years.

MacCulloch was a prolific scientific author, writing not only on geology, medicine and chemistry but on varied subjects such as methods of transferring the habitat of saltwater fish to freshwater and horticulture. His most noted geological works were 'A Description of the Western Islands of Scotland' (1819), 'A Geological Classification of Rocks' (1821), 'The Highlands and Western Islands of Scotland' (1824) and 'The System of Geology' (1831). MacCulloch's 'Proofs and Illustrations of the Attributes of God' which connected theology and geology was published by his widow in 1837.

He married Louisa Margaretta White on 6 July 1835, but on whilst on honeymoon in Cornwall was thrown from his carriage and suffered severe leg injuries. Despite an operation to amputate his leg, John MacCulloch died on 20 August 1835.