He turned his sharp wit on the elders and the clergy of the city, satirising religion and delighting his students. Knox routinely referred to the Bridgewater Treatises as the "bilgewater treatises" and his 'continental' lectures were not for the squeamish. John James Audubon was in Edinburgh at the time to find subscribers for his "Birds of America". Shown round the dissecting theatre by Knox, "dressed in an overgown and with bloody fingers", Audubon reported that "The sights were extremely disagreeable, many of them shocking beyond all I ever thought could be. I was glad to leave this charnel house and breathe again the salubrious atmosphere of the streets". Knox's school flourished and he took on three assistants, Alexander Miller, Thomas Wharton Jones and William Fergusson.