It must be hard to get noticed, as pot stocks proliferate. Witness last week’s announcement by Vireo Health International, one of the smaller multistate cannabis sellers. It brands itself as “science-focused” and physician-led. Last Thursday, Chief Executive Kyle Kingsley, M.D., said the U.S. Patent and Trademark Office had allowed his application for mixing cannabis-derived substances with tobacco—an invention that sounds a lot like the marijuana-laced cigarettes that Americans call a spliff.