'The expertness of his healer': Diagnosis, disclosure and the power of a profession.

Diagnosis is one of medicine's most important tools. It structures the relationship between patient and diagnostician, organises illness and provides access to resources. In this article, I reveal how the manner in which a serious diagnosis is revealed creates a kind of 'epistemic posture' reinforcing the power of medical knowledge, and contributing to medical authority. To achieve this, I explore historical material written by and for doctors about the disclosure of difficult diagnoses. Using historical data for sociological purposes follows Zerubavel, who asserts that phenomena should be studied across eras, media and cultures. I have chosen to focus on how diagnostic disclosure, as described by mid-19th to mid-20th century doctors, serves to promote the profession of medicine. The means of revealing a diagnosis served as a demonstration of, and a means for deflecting threats to, medicine's esoteric nature. The historical data provide a novel approach for understanding how diagnosis operates, even today, to confirm the professional status of the doctor.