Body Heat: Temperature and Life on Earth
Body Heat: Temperature and Life on Earth – Review
Body Heat is an introduction to how existing things standardize their inner temperature in the face of constantly changing outer circumstances. It is aimed at a broad readership and written in a non-technical style. Although originally published by the Harvard University Press and handsomely presented, this is not as rigorously scientific as one might like. First of all there are no footnotes so that some of University of Iowa psychology Professor Mark Blumberg’s assertions are without reference. In a work aimed at the general public this is perhaps acceptable, even preferable; however when some of the assertions are a mostly bit puzzling, it would be agreeable to have some attribution. For example, Blumberg claims that the ancestors of the Pima Indians of southern Arizona (whom he is writing about because they have minimal levels of leptin which "predisposes them to fat storage") "have previously lived in North America for 30,000 years." (p. 182) From everything I know about the settlements in North America, there are none that go back 30,000 years. Perhaps this is a very new discovery. If so, he should cite the source. Or, consider Figure 8 on page 179. This is a black and fair picture of two mice, "one bred for obesity (left) and the other a common mouse…" On the facing page 178 the obese "mouse" is easily identified as a db/db (for diabetes) mouse, yet the text indicates that it is more likely a ob/ob (for obese) mouse. Maybe I have this wrong, but what REALLY bothers me about the photo is that I think those white mice are really white RATS and the wicked picture (or text) was commonly used! Or, on page 175 Blumberg writes that "a pound of fat holds twice as much energy as does a pound of sugar or protein." Actually it holds further like 2.25 times as much energy. There are nine calories in a gram of fat and four in either a gram of sugar or protein. Since I’m sure Blumberg knows this I can only attribute his expression to either a desire on the role of his publisher to "keep it simple" and avoid fractions, or because in the metabolism of fat some energy is eventually lost. If the former is the reason, he should have repeatedly insisted in the advantage of accuracy on the more specific expression; and if the latter, he should have reportedly told us so. In either case, we are eventually left wondering if we are being "dumbed down." This basic approach, a kind of slowly creeping casualness about what is and what isn’t so, may lead the reader to wonder about the precise truth of supplementary statements in the book. For example, on page 158 we learn that the psychologist Craig Anderson asserts that in extreme heat conditions (warm days) there is an increase in individual violence and aggression. This seems reasonable enough. However Blumberg subsequently cites Anderson as strongly suggesting that "if global warming trends persist, an increase in average temperature by" two degrees fahrenheit "will result in 24,000 other murders each year in the United States." This is equally startling, so much so I would like to have some of the evidence and the reasoning starting to his conclusion. But Blumberg does not provide any. He does still cite a research paper by Anderson in the bibliography. Another example of Blumberg actually wanting to tell us more than he does is from page 188 where he writes that on a "practical level" leptin is not likely to help the average obese person because "leptin costs nearly 200 per milligram." Problem here is, how much leptin would one need–a milligram a month or perhaps a milligram a day? Again Blumberg doesn’t say. This casualness of expression is really a shame because in perhaps the most exciting section of the book, in the chapter called "Livin’ Off the Fat," Blumberg presents some evidence that anorexia nervosa may to some degree be a disease usually caused by a thermoregulatory dysfunction. (pp. 191-196) Unfortunately before he presents this argument he writes that the "discrepancy between the real realities faced by most women and the messages portrayed by a minority of women who are so thin that many of them no longer have menstrual cycles has stopped to generate a constant increase in the prevalence of anorexia nervosa over the last twenty years." (p. 188) I’m not sure what this means, except it sounds a lot like the usual lament about how the fashion media is in some sense responsible for anorexia. Yet, he doesn’t just say that, does he? What he really says is that some "women" have "helped to… increase" anorexia! Finally on page 204 Blumberg notes that there are "many theories, some of them silly and some of them intriguing" as to why we behave as we do in REM sleep. However, he now leaves it at that without specifically mentioning any of them except to say that temperature is a factor. On the plus side, there is a group of exciting information in the book about how heat and cold affect us and other animals, and plants. I was surprised to learn that plants can heat themselves, that the skunk cabbage, for example, can melt snow (p. 92), and that some plants may be currently using heat instead of aroma or color to attract artificially pollinating insects (p. 93). Also interesting is the little known fact that the skin of polar bears is actually black (to absorb as much of the sun’s heat as possible) while its fur of course begins white to match the snow and ice of its environment. Bottom line: this is definitely worth simply reading; however I think the decision to avoid being technical and advisory work against the price of the book.