Tobacco for adults, cocoa for kids I was interested in the report of cacao-beverage use by people of Chaco Canyon in New Mexico as early as A.D. 1000 (“Hot chocolate, with foam please,” SN: 2/28/09, p. 14). In the late ’50s, I and others at the Philip Morris Research Center looked at pipe samples from the Four Corners area (Arizona, New Mexico, Colorado and Utah) dating from about A.D. 900. The pipes were submitted by archaeologists from the University of Arizona who wanted to know if tobacco had been used. Initially, microscopy showed plant structures similar to tobacco and also ... (p. 30)

Hormones, milk and fat I find it difficult to understand why the hormone content of skim milk is greater than that of 2% low-fat milk, which in turn is greater than whole milk (“Scientists find a soup of suspects while probing milk’s link to cancer,” SN: 3/28/09, p. 5). To the extent that 2% and skim milk are produced from whole milk, removing some or essentially all the fat, I would have expected the relation to be reversed. Is there an explanation for why the hormone content of milk increases as fat is removed? Jerry Kerrisk,Santa Fe, N.M. The researchers were just as... (p. 31)

Don’t dismiss Lamarck Your January 31 special birthday edition on Darwin (SN: 1/31/09, p. 17) was excellent, but I believe that science has allowed Jean-Baptiste Lamarck’s contributions to be overshadowed by Darwin’s. The change that can occur to an organism’s genetic makeup during its own lifetime harks away from Darwin’s slow evolutionary process by chance mutations and argues toward Lamarck’s heritable changes within a lifetime. Robert Powell, Austin, Texas Take a vote of biologists today and Darwin will win hands down. But I predict that in 20 years that will change, and... (p. 30)

Why good looks look good The article “It’s written all over your face” (SN: 1/17/09, p. 24) made me recall another article (a couple of years ago, I think!) describing the work of researchers investigating an apparent human, obsessive need to identify patterns in our environment. The scientists studied stockbrokers with and without a specific type of brain injury. The results led the researchers to conjecture that this obsession is hardwired into our brains at a very basic, primitive level. Their thinking was that perhaps our pre-cognitive ancestors developed this obsession a... (p. 31)

Impossible view In “Milky Way puts on weight” (SN: 1/31/09, p. 8), you claim to show an image of the Milky Way. This image cannot be real. Worse, it creates misconceptions: As a college educator, I find that most students actually believe NASA has launched probes outside of the Milky Way to take pictures of our galaxy. I hope that printing a correction will help dispel that belief. Don McCarthy, Tucson, Ariz. McCarthy, of the University of Arizona’s Steward Observatory, was one of a number of readers who pointed out the impossibility of taking a “real” image of the ... (p. 30)

Galaxy clusters slide Could the general motion of galaxy clusters (“Galaxy clusters slide to the south,” SN: 10/25/08, p. 12) be evidence of rotational motion of the matter components of the universe on a scale much larger than the observable universe? Would such motion not also result in accelerating expansion of the observable universe, as gravitational attraction opposing rotational expansion weakened as a result of expansion? Arden Slotter, Castle Pines North, Colo. “The question of an overall rotation for the universe is an interesting one,” says Glenn Starkma... (p. 30)

Goodbye structures Though it is extremely regrettable and unfortunate that plastic museum artifacts are degrading (“Long live plastics,” SN: 11/8/08, p. 34), the ultimate demise of these pop polymers will not have dire consequences. The same statement can’t be made for all of the plastics that have gained common usage in the construction industry since the 1970s. Plastics abound in modern construction. Many plastic items are sequestered in hidden places. PVC drain and vent pipes, Styrofoam and other types of plastic insulation, vinyl window frames, insulation on wiring, lightin...

Right-left preference In the article “Body in mind” (SN: 10/25/08, p. 24), Dr. Casasanto speaks of results with people who are left-handed or right-handed. But no mention is made of people who are innately ambidextrous, as in my family. Has he worked with any of these people? What about people who are almost ambidextrous but not totally? I notice the quality runs in families, but since it is stronger or weaker depending on the individual, I would conclude several genes play a role. Tana Hemingway, Mesquite, N.M. “Everyone falls somewhere along a continuum from right- to left-han...

Big black holes An alternative explanation of why ultramassive black holes reaching 10 billion solar masses seem to go dormant (“Ultramassive: As big as it gets,” SN: 10/25/08, p. 18) could be that in these black holes, the violent activity associated with smaller black holes is completely contained within the event horizon and thus removed from any observation. The tidal forces at the event horizon, which cause the observable effects, actually diminish as the mass and radius of the black hole increase. At a 30-billion-kilometer event horizon, the tidal force is so weak that the largest...

A better way The article “Thinning fuel before injection boosts efficiency” (SN: 10/25/08, p. 9) shows that there are many ways to find efficiency when we look. One place I see for improvement is moisture injection in the feed airstream to gasoline engines. Here in the Southwest, where humidity runs at 20 percent, rainy days are associated with an increase in gas mileage because the moisture turns to steam in the engine and improves efficiency. Moisture injection should be less complex to accomplish than adding a strong electric field. Michael Daly, Gallup, N.M. Good degradatio... (p. 31)