Cancer: the evolutionary legacy

The author's style is both pleasantly idiosyncratic and numbingly methodological. He first looks for instances before 1768 in which clinicians described diseases that resemble angina pectoris, and finds only ten clinical reports that could possibly represent angina. This paucity of cases is contrasted with the rapid proliferation of clinical reports after 1768. It is also striking that for the first few decades after Heberden's presentation reports of angina pectoris came almost exclusively from England. To explain these findings, the author carefully examines changes in food intake resulting from the agricultural revolution of eighteenth-century England, including changes in the ingestion of fats, fish, fibre, sugar, and coffee. He concludes that the most important result of the agricultural revolution was an increase in the year-round consumption of animal fats from meat, poultry, eggs, and dairy products. In addition, a decrease in strict observance of religious constraints on diet may have led to a decrease in the intake of fish and an increase in the intake of fatty animal foods. These nutritional changes were, the author argues, the main reasons that angina started to become a common disease. Michaels also considers the effects of tobacco, hypertension, stress, and exercise on the incidence of angina. He examines an extraordinarily wide range of sources for his arguments, including many contemporary clinical studies, the detailed analysis of which may be tough sledding for non-clinically trained historians (but which may not be essential for the book in any event). Many of these clinical studies take the reader on dizzying leaps from past to present and back into the past again. Much of the reader's reaction to the book will rest, first, on whether one is willing to take absence of evidence (for angina pectoris before 1768) as evidence of absence (of the disease). Next, the reader will have to decide whether she or he is willing to accept clinical and scientific data from the present applied to the past. The author assumes multiple continuities between past and present, but there is little evidence to support (or to refute) almost all of these assumptions. Whether or not one winds up agreeing with the author's primary hypothesis, anyone who wonders about the question of whether angina pectoris existed before 1768 is likely to learn something interesting from this book. Contrary to the view held by some that cancer is a product of industrialized societies, no more than around 5 …