No Ground Wire on Nightlight?

I bought a photocell nightlight that you install into a junction box. It was from a thrift store but new in the packaging. The instructions say it should have 3 wires, but it only has 2. The white and the black. There is no ground wire. There isn't even a place where it looks like a wire would come out of. The white and black wire clearly have holes in which they come out of the nightlight and there is not another hole in where it looks like a wire is missing. Can I still use this night light without a ground wire?