The Vas Hermeticum — the sealed, hermetically closed vessel of alchemical operation — occupies a position of singular theoretical density in the depth-psychological corpus, functioning simultaneously as material instrument, cosmological symbol, and psychological metaphor. Jung's sustained engagement with the term, most fully elaborated in Psychology and Alchemy and The Practice of Psychotherapy, establishes the vessel as far more than a laboratory apparatus: it is a mystical idea, a 'true symbol,' whose roundness imitates the spherical cosmos and whose sealed interiority creates the preconditions for transformation. The vessel must contain what cannot otherwise be contained — the volatile Mercurius, the aqua permanens, the warring opposites — and its hermetic closure is the very condition of the opus. Jung's psychological reading displaces this containment function onto the therapeutic temenos and the analytic relationship itself, identifying the vas Hermeticum as the structural analogue of the bounded psychic space within which the coniunctio oppositorum can proceed. Von Franz deepens this reading by attending to the vessel's feminine, uterine associations — concave, closed, generative. Campbell registers the symbol's wider mythological resonance. The central tension in the corpus concerns whether the vessel is primarily a cosmic model, a psychological container, or a figure of the maternal feminine — a tension the sources do not so much resolve as hold in productive suspension.
As the vas Hermeticum of alchemy, it was 'hermetically' sealed (i. e., sealed with the sign of Hermes); it had to be made of glass, and had also to be as round as possible, since it was meant to represent the cosmos in which the earth was created.
Jung identifies the vas Hermeticum as a cosmological symbol requiring hermetic sealing and spherical form, representing the cosmos as the containing vessel of creation.
, Alchemical Studies, 1967thesis
The basin below is the vas Hermeticum, where the transformation takes place. It contains the mare nostrum, the aqua permanens or fiScoo Mov, the 'divine water.' This is the mare tenebrosum, the chaos. The vessel is also called the uterus.
Jung equates the vas Hermeticum with the transformative site of the alchemical opus, identifying it as the container of the divine water and, crucially, as uterus — the generative feminine matrix.
, Collected Works Volume 16: The Practice of Psychotherapy, 1954thesis
It must be completely round, in imitation of the spherical cosmos, so that the influence of the stars may contribute to the success of the operation. It is a kind of matrix or uterus from which the filius philosophorum, the miraculous stone, is to be born.
Campbell, summarizing Jung, articulates the vas as simultaneously cosmological model, stellar receiver, uterine matrix, and paradoxical symbol that is both water and fire — a vessel whose identity collapses into its contents.
, Creative Mythology: The Masks of God, Volume IV, 1968thesis
The vas is often synonymous with the lapis, so that there is no difference between the vessel and its content; in other words, it is the same arcanum.
Jung articulates the paradox of the vas as indistinguishable from what it contains, collapsing the boundary between container and content into a single arcane substance.
, Aion: Researches into the Phenomenology of the Self, 1951thesis
Vas nostrum ad hunc modum esse debet, ut in eo materia regi valeat a caelestibus corporibus. Influentiae namque caelestes invisibiles et astrorum impressiones apprime necessariae sunt ad opus.
Jung cites Dorn to establish that the vessel must be open to celestial influences — a cosmological-magical requirement that elevates it beyond mere laboratory equipment.
, Psychology and Alchemy, 1944thesis
The deposit corresponds to the corpse in the sarcophagus, and the sarcophagus corresponds in turn to the mercurial fountain or the vas hermeticum.
Jung links the vas hermeticum to the sarcophagus and mercurial fountain, extending the vessel's symbolic range to include death, putrefaction, and the nigredo phase of transformation.
, Collected Works Volume 16: The Practice of Psychotherapy, 1954supporting
vas Hermeticum, 203, 240/f, 256, 284; feminine lunar vessel, 312
The index entry from The Practice of Psychotherapy confirms the vas Hermeticum's explicit association with the feminine and lunar dimensions of the alchemical vessel in Jung's clinical-symbolic thinking.
, The Practice of Psychotherapy: Essays on the Psychology of the Transference and Other Subjects, 1954supporting
The underworld tripod embodies the feminine chthonic trinity (Diana, Luna, Hecate, and Phorkyads). It corresponds to the vas hermeticum (and the early Christian communion table of the catacombs with 3 loaves and 1 fish).
Jung maps the vas hermeticum onto the chthonic feminine trinity of Faust's underworld tripod and the early Christian communion table, demonstrating the term's transhistorical symbolic reach.
, Collected Works Volume 18: The Symbolic Life, 1976supporting
In order to catch the soul God created the vas cerebri, the cranium. Here the symbolism of the vessel coincides with that of the head... the symbol of the vessel gets transferred to the soul.
Jung traces the vessel's symbolism from the vas cerebri (skull) through to the soul, showing how the container motif migrates from matter to psyche in alchemical and patristic thought.
, Collected Works Volume 3: The Psychogenesis of Mental Disease, 1907supporting
Vas hermeticum, 255 (226)
Campbell's index entry locates the vas hermeticum within The Mythic Image's broader comparative mythological framework, confirming its place among universal symbolic forms.
, The Mythic Image, 1974aside
Hermes' seal the hermetic seal which closes the alchemical vessel and keeps it airtight by either fusion or welding. The sealing not only keeps the mixture in the glass vessel secure from the intrusion of outside influences, but also makes sure the mercurial contents do not escape.
Abraham's lexicographical entry on the hermetic seal illuminates the technical function underlying the vas Hermeticum's symbolic power: the seal that protects the volatile Mercurius from dispersal.
, A Dictionary of Alchemical Imagery, 1998aside
The prima materia was considered to be virginal, and the distilling vessel had breastlike openings from which the distillate was poured.
Von Franz documents the ancient attribution of feminine, lactating bodily form to the alchemical vessel, reinforcing the uterine-maternal symbolism Jung associated with the vas Hermeticum.
, Aurora Consurgens: A Document Attributed to Thomas Aquinas on the Problem of Opposites in Alchemy, 1966aside