Carl Jungian was a famed psychologist. Not only because he was the prodigy of Sigmund Freud who, according to Jung's biography, criticized him (and parted with him professionally) for straying away from the scientific path. Not only because he created the concepts of introvert and extrovert...and not only of his other contributions in analytic psychology. He was, according to some of his prodigies, an alchemist. Not too surprisingly if one came to know that the great Isaac Newton was foremost an alchemist and doing physics as his "leisure pursue".
According to "Jung and the Alchemical Imagination" written by Jeffery Raff who studied under Marie-Louise von Franz in Zurich (Marie was Carl Jung's prodigy on the alchemical side), meditation was being practised by the psychologists studying in the Institute, as part of the curriculum. No details of meditation techniques were discussed in the book which focused on explaining psychological side of the Jungian individuation process (they used meditation and alchemical imagination as the route of progress). The fact is an outsider, be it a teacher or an uninformed observer, cannot witness the transformation process inside a person's body and mind. We have to depend on proxy to gauge the process. And the proxy those Jungian psychologists used was alchemical imagination.
The stages of transformation as depicted in Raff's book, for exposition purpose, were taken from alchemical texts in the West. What surprised me is that the three stages of transformation look very much the same (or at least alike) as those depicted in a Taoist Neidan classic, none other than the famous Taoist Yoga translated into English by Charles Luk (at the encouragement of Carl Jung).
I suspect most readers of Western alchemical texts (or as introduced by Jungians) and Taoist Neidan (deep mediation) do not cross path. Taoist texts focused more on techniques while alchemical texts focused on empirical internal images. I have seen practitioners in the West eagerly search for and read loads and loads of arcane books trying to find the best route to salvation (yet still puzzled after years of pursue) and practitioners in the East spending years to learn to control their breath and seeking for lights as internal sensation for guidance without understanding what their practice can do to their personality (or self).
Perhaps it has come to the day when East shall truly meet West. And Taoist Neidan texts shall be studied and be practised side by side with Jungian alchemical texts and experience, for the benefit for any practitioner.