Factual error: Tom Hanks refers to an Intensive Care Unit, and although a few physicians had already discovered the practice of separating the sickest patients into a separate ward in the 1930's, the term Intensive Care Unit was not yet in use.
Factual error: The movie is set in 1935 Lousiana, and all of the executions are through electrocutions. However, executions by that method in that state didn't happen till 1941.
Factual error: When Paul returns home, his wife asks him what the doctor said. He replies "...gobbledygook mostly." The trouble is, the word "gobbledygook" wasn't coined until 1944. This scene takes place in 1935.