In 1825, John Barclay offered him a partnership at his anatomy school in Surgeon's Square, Edinburgh. In order for his lectures to be recognised by the Edinburgh College of Surgeons, Knox had to be admitted to its fellowship; a formality, but, at £250, an expensive one. At this time most professorships were in the gift of the town council, resulting in such uninspiring teachers as the professor of anatomy Alexander Monro, who put off many of his students (including the young Charles Darwin who took the course 1825–1827). This created a demand for private tuition, and the flamboyant Knox—in sole charge after Barclay's death in 1826—had more students than all the other private tutors put together.