[1] In 1919, aged 18, Thomas participated in Herbert Basedow's medical expedition to outback South Australia and adjoining portions of Queensland.
While mapping the spread of the disease on Kangaroo Island, he realised that it was largely confined to areas with calcareous soils, lacking certain heavy metals that were known to be essential animal nutrients.
By referring to earlier German experiments with rats, he correctly hypothesised that a cobalt deficiency was the primary cause of the disease, which was later confirmed experimentally by the division's head Hedley Marston.
[9] Wark later said of him that "this one man's initiative has led to interesting and valuable work for two hundred people, all of whom have, of course, helped to build on the foundations of Thomas".
[13] Their experiments involved inducing the odour by steam distilling rocks that had been previously exposed to warm, dry conditions.
The paper identified that the odour derived from a "yellowish oil" that was released from rocks and soils when their pores were infiltrated by moisture.
His ashes were scattered over Mount Painter in the Flinders Ranges, and a memorial plaque was erected by his friend Reg Sprigg, founder of the nearby Arkaroola Wilderness Sanctuary.