The device, called a JuJu Joint, heralds a union that seems all but inevitable: marijuana and the e-cigarette, together at last in an e-joint. For years, people have been stuffing marijuana in various forms into portable vaporizers and into the cartridges of e-cigarettes. But the JuJu Joint is disposable, requires no charging of batteries or loading of cartridges, and comes filled with 150 hits. You take it out of the package and put it to your lips — that’s it. There is no smoke and no smell.