Character Analysis
The "Professor N." Freud mentions in his "Autodidasker" Dream (6.2.53) is probably not the same "N." he mentions in his Dream of Uncle Josef (4.1.10-11). "Professor N." was probably a father-figure of some sort (source), which is why dream-Freud goes to him for medical advice.
Although Freud doesn't tell us the real identity of the man he refers to as "Professor N.," the figure seems to share striking similarities with Joseph Breuer and Ernst Wilhelm von Brücke.