©Wellcome Library, London

In this photograph, the surgeon, Sir Victor Horsley (1857-1916), is standing on the left wearing a face mask and rubber gloves although he is the only person in the operating theatre to do so. The others are wearing outdoor clothes under gowns or white coats while the nurses wear standard ward uniforms. In addition, Horsley's abdomen was encased in antiseptic dressings in preparation for the removal of his appendix the following day!

Source: Stephen Paget. Sir Victor Horsley. Constable, London 1919.