After doing post-graduate work at Paris he was for some time demonstrator of anatomy to Professor J. Cantlie at the Charing Cross Hospital medical school.

In 1883 he went to Egypt as surgeon with Hicks Pasha's Sudan force, and in 1885 became first Elder professor of anatomy at the newly founded medical school at Adelaide.

[3] He taught also pathology (showing an early interest in biological means of controlling the rabbit pest),[4] surgical anatomy, and operative surgery.

When World War I broke out in 1914, though 65 years of age, Watson left Australia with the first expeditionary force as a major in the Royal Australian Army Medical Corps and became consulting-surgeon and pathologist to No.

[1] Watson visited China, South America, Japan, Russia and New Zealand, where he usually watched leading surgeons perform operations; although he regarded Sydney's Sir Alexander MacCormick as superior.