Originally trained as a surgeon, Tonks had qualified FRCS in 1888 before abandoning medicine to follow a career as an artist. Tonks became “the most renowned and formidable teacher of his generation”.Pupils of Tonks at the Slade included Winifred Knights, David Bomberg, Ethel Carrick, William Lionel Clause, Mukul Dey, Ian Fairweather, Mark Gertler, Harold Gilman, Spencer Gore, Katie Edith Gliddon, Edna Clarke Hall, Augustus John, Gwen John, Percy Wyndham Lewis, Hyam Myer, William E.C. Morgan, William Orpen, Isaac Rosenberg, Stanley Spencer, and Rex Whistler. His sarcasm there drove F. M. Mayor’s sister Alice to leave before completing her training.His student Paul Nash recalled Tonks’ withering manner:
“Tonks cared nothing for other authorities and he disliked self-satisfied young men‚Ķ.His surgical eye raked my immature designs. With hooded stare and sardonic mouth, he hung in the air above me, like a tall question mark, moreover‚Ķ of a derisive, rather than an inquisitive order. In cold discouraging tones he welcomed me to the Slade. It was evident he considered that neither the Slade, nor I, was likely to derive much benefit.”