A catling (also spelled catlin) is a long, double-bladed knife used in amputations. It's rather medieval, if I remember correctly. I know it was used a great deal back in the eighteenth century, when the remedy for almost all ailments of the limbs was amputation. (Got an unsightly hangnail? Chop the finger off!)
Grrr. **Eye twitches.** As if Robin will actually be able to walk up enough to understand me.