John Huxley Mason qualified (MRCVS, Glasgow) in 1920. After practicing for three years he took a post-graduate course in bacteriology and from 1922 lectured in bacteriology at the Glasgow Veterinary College. In 1924 he was employed at the Wellcome Research Laboratories at Beckenham in Kent, where he served as one of the pioneers in the study of toxigenic anaerobes. He obtained a FRCVS in 1927 and a year later was elected a Fellow of the Royal Society of Edinburgh. In 1931 he was appointed as an Empire Marketing Board Research Fellow at the Veterinary Research Institute, Onderstepoort. Here he continued his research on Clostridial anaerobes, for which he was awarded a DVSc degree by the University of South Africa in 1936.
Mason extended his interests to other topics, in each of which he made original contributions to knowledge. With Dr R.A. Alexander* he studied heartwater and blue tongue in sheep, and then, in collaboration with staff at the South African Institute for Medical Research (SAIMR), the rickettsial diseases of humans - epidemic typhus fever, murine typhus and tick bite fever. They showed that the rickettsiae causing these diseases grew prolifically in the tissues of developing chicken embryos, a finding which formed the basis of the large scale production of typhus vaccine.
In 1941 Mason moved to the SAIMR to take charge of the Anaerobic Bacteria Laboratories. Here he was responsible for the production of diphtheria and other antisera. He also collaborated in the study of Salmonella typhi and the production of immunity to typhoid fever in man. In 1945 he succeeded Dr E. Grasset as superintendent of the Serum and Vaccine Division. Either ten or fifteen years later he was promoted to the post of deputy director of the institute, a post he held until his retirement in 1975. He was author or co-author of 110 scientific publications. From 1946 to 1950 he was president of the South African Veterinary Association and in 1976 was awarded its gold medal for "distinguished service to the veterinary profession". He was dedicated to his work, meticulous in all he did, and his staff regarded him with respect, admiration and affection.