Small-time marijuana growing is already a big business in Canada. It is likely to get bigger, despite all the efforts of the antidrug crowd in Washington, D.C. On Oct. 14 the U.S. Supreme Court, by refusing to disturb an appeals court ruling, gave its stamp of approval to doctors who want to recommend weed to ease their patients' pain or nausea. In the U.S. nine states have enacted laws permitting marijuana use by people with cancer, AIDS and other wasting diseases. The Canadians are even more cannabis-tolerant; although they have not legalized the drug, they are loath to stomp out the growers. This illicit industry has emerged as Canada's most valuable agricultural product- -bigger than wheat, cattle or timber.