The drain hole in the bathtub, which is simply a means of the water draining away, at some point over the years acquired a contraption, a device meant to raise and lower but remain in place. The original 1906 drain would not have had this: it would have had a simple hole and a simple plug. Perhaps it became a modern thing to hide the hole in the tub. It also hides – and collects – hair and soap scum and facecloth fluff. Yuck!
Now this particular contraption either broke off or was yanked off at some point before my arrival. What remains is a stump. A stump that will not allow a plug to snug into the hole. A stump that will allow a flat piece of rubber to take up suction but which may suddenly let go if nudged by a toe or hold firmly even when pried with fingernails.
Showers-only is one solution. Claw foot tubs are meant for bathing. The plan is to clearcut the stump and hopefully regain a simple drain hole and a simple plug.