How was it attached originally? Was it glued? Can you tell what kind of glue? You can buy hide glue (if that was what was used originally) in the liquid state at some hardware or woodcrafting stores or at Woodcraft.com. Experiment with it first, though — it’s a very thin liquid and can be extremely messy. When it is dry, it’s kind of golden brown and brittle. Or you can get a neutral Ph white glue, which is a thicker and drys clear and a little flexible, from either Gaylord or University Products.