The history of disease and disease concepts are aspects of medical history fraught with problems and yet full of possibilities. The history of ‘consumption’ before Robert Koch is only partially continuous with the history of ‘tuberculosis’ after him. In one sense, the history of myocardial infarction begins only about 1900, even though men and women suffered from arteriosclerosis before that date. The history of chlorosis has been conceived in terms of diet, anaemia, and other physical categories on the one hand, and in terms of social relations and repressed women on the other. ‘Hysteria’ has been recently written about as largely misdiagnosed epilepsy by one historian, and as a kind of alternative career for women denied adequate avenues of social expression by other historians. 1 The fascination with retrospective diagnosis so beloved by practising doctors who turn their attention to history has been castigated by historians who find the exercise distortive, Whiggish, and historically irrelevant. To ask, for example, what was ‘really wrong’ with Napoleon or Darwin has been seen as asking an unanswerable question, or as encouraging speculation in excess of the evidence. Those who have insisted that it is the historian’s proper task to try to understand the diagnostic categories and therapeutic options available to a doctor at any particular time only within the terms of his own society are responding to a real historical problem, for our own knowledge of the afflictions of earlier generations is often limited by what they and their doctors made of it. In the end, we may well be forced to conclude that an eighteenth-century lady suffering from the vapours or a nineteenth-century maniac in a Victorian country asylum were afflicted with precisely those diseases. 2