Black OpiumInterest in heroin is surging back after years of dormancy. Why? Supply and demand! Drug cartels have increased the supply of heroin, so that it is cheaper and purer than ever before. Secondly, the Federal government's recent crackdown on popular prescription opiates like OxcyContin, Percocet, and Vicodin means they are increasingly hard and costly to obtain on the black market. A recent study reveals that people who had recently abused prescription