Surgical lesson. Early 20th-century surgical theatre with surgeons operating and an anaesthetist at lower left. The anaesthetist is using a bottle to apply anaesthetic for the patient to inhale. Nurses and a student are watching across top. The large windows at upper left allow the operation to take place in sunlight, with light bulbs at upper right if further illumination is needed. Photographed in the USA in around 1905, possibly at Johns Hopkins Hospital.