I really want to guess this one right so I can post a picture. Normally I'd post a shoe string or a light bulb b/c I have no idea where to find these things that y'all come up with, but I have one in mind now.
It was used for a common procedure during that time frame. this one is thought to have been used on both humans and animals.
That was my next guess. However, we used to just use a pocket knife. I knew a dude who used his teeth.
Man... mention medical and we immediately get hemorrhoids, foreskins, and castration. Think a little outside the britches. They used this to perform a medical procedure that was thought to be a treatment for a host of ailments.