I don't remember the details of that scene, but I don't think I ever considered it hypnotism. It seemed that it was just his "powers" in general, or partially the force of his personality, that he was able to command her and eventually get her to respond.
As Josete said, I think it was one of his powers, probably related to the hypnotism ability, but not involving direct eye contact. The vampire's will is overpowering.
That is probably what it was, but you know something. I kind of got the impression that Gerard was more powerful than Barnabas was in the 1995 scenes. I always thought it was because Gerard was evil and Barnabas wasn't during those scenes.
Which brings up Gerard's control over Julia. Gerard actually got Julia to betray Barnabas by getting her to reveal he was a vampire to the authorities.
Which is why I wondered if when Barnabas was able to get Julia to respond to him. It was because Barnabas had a deeper connection with her that allowed him to overcome Gerard's control over her. I know they were friends, but that didn't stop her from betraying Barnabas. So I was wondering if that scene was revealing a deeper connection between Barnabas and Julia that had not been revealed before.
Of course they could have been throwing the Barnabas/Julia fans a bone after having to listen to Barnabas go on and on about his feelings for Roxanne in front of Julia.
FireRose