Plants and rheumatism Some medical specialists in the field of rheumatology might find it useful to review the work of Ann M. Hirsch and Angie Lee, mentioned in the article by Susan Milius (SN: 4/12/08, p. 235). It describes a process in plant fixation of nitrogen involving biological action that seems to attract calcium. Perhaps a similar action occurs in human bone joints, causing the attraction of calcium in rheumatism. Roger W. Otto, San Mateo, Calif. A pervasive hidden influence “Dad’s Hidden Influence” (SN: 3/29/08, p. 200) states that, “Fathers 40 and older have an increased chance that their children will develop complex disorders such as autism or schizophrenia.” Our society’s trend for couples to wait until they are much older to have children may be the reason for the increase in autism. The medical field tells us better identification is the reason for the increase in children being identified as mentally ill, but maybe the increase is due in part to older parents. Julie Nelson-Thiele, Eugene, Ore. Keep reverence in its place Hats off to Ms. Ehrenberg on her “Digging that Maya blue” piece (SN: 3/1/08, p. 134). She didn’t sugarcoat (in a politically correct manner) ancient human sacrifices as admirable religious rituals. It’s bemusing that some readers feel that the practice of human sacrifice should be treated today with religious reverence. Even the Romans (who are now considered pretty barbaric) stopped religious human sacrifices in the regions they conquered more than 2,000 years ago. Brian Voyce, Chapel Hill, N.C. Comments on the new Science News: Eager to see the new format, but really liked the “weekly” publications. I hope the fortnightly editions are as informative. Most importantly, don’t drop the Letters, as they are the first thing I read (even though you put them in the back of the weekly a few years ago). Without them I won’t know if I missed anything interesting from past articles, which I do go back and review. Regards … and cheerio. Steve Wellborn, Chellaston, United Kingdom Please, please, please retain the witty, lighthearted flavor of the article headlines, which have been an essential, engaging characteristic of the magazine for all the four decades I have subscribed. Thanks a lot. Fredric Blum, Merion, Pa. Good medicine (usually) Regarding “Raising doubts about Crohn’s treatment” (SN: 3/8/08, p. 157): My sister was diagnosed with Crohn’s disease two years ago at the age of 46. She was given high doses of prednisone, which did not relieve her symptoms and which also made her depressed, extremely anxious and sleepless. After many long, scary months she was started on the infliximab-azathioprine combination, the new treatment discussed in your story. She went into remission, and the mental side effects dissipated almost overnight. She is still in remission today, a year later. But it should be mentioned that, while infliximab and azathioprine are blessings for many people, they are not benign. They have been associated with an increased risk of infection and non-Hodgkin’s lymphoma. Rachel Leibman, Montclair, N.J. Ah-ha-ha-ha In your article “Road to Eureka” (SN: 3/22/08. p. 184), you discuss “Aha!” moments. The same sort of lateral thinking and feelings occur when you “get” a joke. In fact, in parallel to when the subjects were given hints in the research your article discusses, a lack of such a moment often occurs when someone has a joke explained to them. I would not be surprised to see similar brain activity for subjects listening to jokes and perhaps even a correlation between an active sense of humor and insight. Perhaps humor and puzzle solving are a form of cross-training exercise for our brains? Ethan B. Gallogly, Santa Monica, Calif. Universal recipe “State of the Universe: Microwave glow powers cosmic insights” (SN: 3/15/08, p. 163) argues convincingly and categorically that the contents of the universe consist of 23.2 percent dark matter, 72.1 percent dark energy and the rest ordinary matter. Then comes “From dark matter to light” (SN: 3/22/08, p. 186), where Ron Cowen writes that dark matter “appears to constitute 85 percent of the mass of the universe.” Is this a radical disagreement or just conflicting guesswork, after all? M. David Wolf, San Jose, Calif. The 85 percent refers to what share of the total amount of mass in the universe — just mass — is dark matter, while the 23.2 percent refers to what proportion of mass plus energy is dark matter. —Ron Cowen Send communications to: Editor, Science News 1719 N Street, NW, Washington, D.C. 20036 or editors@sciencenews.org All letters subject to editing.