Do surge protectors work to protect electronics when there is no ground wire in wall outlets? Our house was built in 1911. Most of the electrical is original knob and tube. No ground wire on 3-prong outlets (though many outlets are still two-prong). Can a surge protector really protect our electronic equipment if there is no ground? If not, is there any way to protect our stuff?

No, surge protectors do not operate with no equipment ground. It is this ground that allows a surge protector to drain any surges.

Best you can do is have a new circuit installed for any electronic device that you want surge protection.