Lime and lemon juice could be potent weapons in the fight against AIDS in the developing world, some experts are suggesting. The potency of these citrus fruits lies in their acidic nature, and in the lab their juices have been shown to be effective in killing the HIV virus, explained Roger Short, a reproductive biologist at Australia's University of Melbourne. This property, Short points out, could be a boon in sub-Saharan Africa, a region with 25 million current HIV infections, and another three million new ones reported each year. (See a National Geographic magazine feature on AIDS in Africa.) Short...