When Parris is speaking to his instructor in Vienna, Dr. Kendell strikes a match to light his pipe. In the next shot, the match has disappeared, and there is no evidence that he lit the pipe.
When Parris's Aunt Marie is talking to the doctor about making a will, her bangs are completely brushed back. When she finishes the conversation and goes upstairs to rest, she stops in Parris's room, and her hair has changed. Now her bangs go across her forehead.
When Randy sends Parris a letter in Europe, the return address reads "Kings Row, USA" with no street address or state indicated.
January 1, 1900 is the first day of the last year of the 18th century. January 1, 1901 is the first day of the 20th century. This is because the years started counting at A.D. 1; i.e., there was no year "zero".