While [Thomas Edison was] an operator at one station, the telegraph office was greatly infested with cockroaches. Mr. Edison tacked several zinc strips to the walls at intervals of an eighth of an inch, and applied the positive and negative poles of a battery alternately to the strips. He next smeared the walls above the strips with molasses. The long legged bugs came up, and as they stepped from strip to strip, they ‘closed the circuit,’ received the electric shock and dropped dead by scores. Water pails put at the proper places received their bodies as they fell.

— James Baird McClure, ed., Entertaining Anecdotes From Every Available Source, 1879