Henry Tonks was a surgeon before becoming an established artist and teacher at the Slade School of Art. During the war he served as a RAMC doctor and worked with Sir Harold Gillies, one of the pioneers of plastic surgery. Tonks drew studies of facial injuries before and after surgery, requiring accuracy, attention to detail and emotional understanding. These qualities are evident in 'Saline Infusion', where the pain of the patient is transmitted through the precisely-rendered tautness of his upper body. The delicacy of the pastel medium, which reflects the mute compassion of the medical staff, contrasts with the hard tension in the man's muscles.