Barmaid's Brain

How can a waitress's brain allow her to remember every drink order at a table but be unable to know that the surface of beer in a tilted glass remains horizontal? Are the earliest human ancestors primates or aquatic mammals? Can mutant genes ever be beneficial? Canadian science writer Ingram (The Science of Everyday Life, etc.) examines these and other mysteries in this lively collection. He shows that science most often does not arrive at its conclusions through any straightforward method of hypothesis and experimentation. Instead, science involves a series of fits and starts as it probes the human psyche, the world of microbes and electrons, and the behavior of animals, often suggesting along the way different answers to the same question. For example, some scientists contend that male moths are attracted to candles because the infrared radiation of the burning wick ""feels"" similar to the infrared radiation that female moths produce in their sexual pheromone. Other scientists argue that once upon a time moths used moonlight to guide their nocturnal flights and that now, confusing porch lights with moonlight, they naturally fly to the first glow they see. In a story about microbiology, Ingram explains how being a carrier for cystic fibrosisDthat is, having a mutant geneDmay offer protection against cholera in the same way that being a carrier for sickle cell anemia provides protection against malaria. Finally, he discusses the ""aquatic ape"" theory of evolution, which holds that our lack of body hair, our subcutaneous fat and our ability to hold our breath argue for a marine, rather than a terrestrial, evolutionary ancestry. In these humorous and winning tales, Ingram displays a genuine wonder for the world around him; pop science fans will enjoy following these entertaining investigations. (Oct.)