Thomas Harvey Johnston

Thomas Harvey Johnston was born on 9 December 1881 at Balmain, Sydney, son of Thomas Johnston, Irish-born foreman mason, and his Australian-born wife Mary, née McLeod. After schooling Johnston joined the education department, won the Jones memorial medal and went to the University of Sydney (B.A., 1906; B.Sc., M.A., 1907; D.Sc., 1911). On 1 January 1907 at Petersham he married Alice Maude Pearce.

Johnston taught at Fort Street Public School in 1903-06, lectured in zoology and physiology at Sydney Technical College in 1907-08 and became assistant director of the Bathurst Technical College in 1908. He was appointed assistant microbiologist at the newly established Bureau of Microbiology of the New South Wales Health Department in 1909. Lecturer in charge of the department of biology in the new University of Queensland from 1911, he was appointed professor in 1919.

Johnston was chairman of a committee formed in 1912 to investigate control measures for the introduced pest, prickly pear, and worked overseas in 1912-14 with Henry Tryon. The two men, known as 'the prickly pair', succeeded in introducing Dactylopius ceylonicus, the cochineal insect which controlled one species of the pear Opuntia monacantha. In 1920 Johnston was appointed controller of the Commonwealth prickly pear laboratories and went overseas again in 1920-22. He had twice collected and introduced unsuccessfully the insect Cactoblastis cactorum in 1914, when it did feed on the pear but died out in 1921. The eventual devastation of the prickly pear by it followed a later introduction in 1924.

Johnston was appointed professor of zoology at the University of Adelaide in 1922, creating a new department, and acted also as professor of botany in 1928-34. Specializing in descriptive parasitology, he was also a world authority on helminthology; he added much new material to the extensive collection of the South Australian Museum. At the invitation of Douglas Mawson he served as chief zoologist with the British, Australian and New Zealand Antarctic Research Expedition of 1929, went on two cruises of the Discovery in 1929-31 and was editor of the zoological and botanical reports. In 1929-37 he participated with John Cleland in many expeditions to Central Australia.

Affectionately known as 'T.H.J.', Johnston was gentle, kindly, hard working, clear thinking and sensitive, with a slow, quiet sense of humour. He lived up to a high ethical code and was in the sense of the Greek philosophers 'a complete man'. He died in Adelaide of coronary thrombosis on 30 August 1951 and was cremated.