Answer:
Teddy thought Dr. Einstein was General George Washington Goethals.
Step-by-step explanation:
The play "Arsenic and Old Lace," by Joseph Kesselring revolves around a family of insane people who 'killed' lonely men to rid them of their loneliness. The story is set in the Brewster family home where a dozen of lonely men were buried in the basement of the home by the aunts, brother, and uncle of the main protagonist Mortimer Brewster.
In Act II, we see Jonathan and Dr. Einstein arriving at the Brewster home. Teddy, who's delusional and thinks himself to be President Theodore Roosevelt, came out of his room and immediately approached Dr. Einstein. He addressed the plastic surgeon, Dr. Einstein, as "General Goethals", with whom he was at "Culebra Cut".