What did the old man ask James to do with the crystals?

The old man gives James the beans, but he warns him to be very careful with them, as the beans are made of crocodile tongues boiled with the skull of a dead witch and the eyeball of a lizard. The old man tells James that once the beans are released, whatever they touch will receive the full magical power. He warns James to be very careful with them.

"Inside, James could see a mass of tiny green things that looked like little stones or crystals, each one about the size of a grain of rice. They were extraordinarily beautiful, and there was a strange brightness about them, a sort of luminous quality that made them glow and sparkle in a most wonderful way."

"Because if they do escape, then they will be working their magic upon somebody else instead of upon you! And that isn't what you want at all, is it, my dear? Whoever they first meet, be it bug, insect, animal, or tree, that will be the one who gets the full power of their magic!"