Let's see here... the late Ormond McGill was a legendary magician as well as one of the leading experts in modern hypnosis both, on stage and at the clinical level (penned nearly 100 books -- big, heavy, thick books -- on the topic). His
ENCYCLOPEDIA OF HYPNOSIS still, after nearly 50 years (I think it is) remains the top ranked resource for anyone wishing to move into stage Hypnosis. . . it's the Corinda of said niche followed by Anthony Joaquin's
REALITY IS PLASTIC of recent vogue.
Going back, not all that far in time, it was quite common for the magician to hypnotize the young lady prior to doing the levitation or any number of other bits (Blackstone did so with the Buzz Saw so as to explain why no blood spilled).
When it comes to Mentalism and how it was done long ago, use of hypnotic & trance inducing methods without the public realizing that it was being used, was quite common (especially in parts of Europe -- Read the book
ERIC JAN HANUSSEN HITLER'S JEWISH CLAIRVOYANT and you'll find example after example of this and more!) This is a technique that a small handful of performers have only recently revived, but under the banner of "Ericksonian Hypnosis" in that conversational hypnosis tends to be credited to the work of
Dr. Milton Erickson in the 50s & 60s.
You will find that most stage hypnotist have always mingled bits of trickery (especially mentalism stunts) with their shows for the sake of production value as well as general astonishment. To my mind however, Hypnosis is akin to Mentalism on the level that it is best to set aside a large portion of your show (at least 30 minutes) if not create a complete show that is nothing but hypnosis or suggestion based material. Such programs typically run no less than 45 minutes to well over two hours depending upon the setting and venue constrictions (stage union locals will insist on precise start & end times).
I'm not too certain how I feel about how Hypnosis is being meshed with magic these days in that it's such a powerful skill that gives one even greater advantage as a stand-alone entity. The psychology alone gives you exceptional benefit when segregated.