Manna is a term used in the bible, according to Merkur,  to refer to various forms of Connection Supplements.
List of Connection Supplements
Connection Supplement > Ayahuasca, Cannabis, Chloroform, DMT, Haoma, Kaneh Bosm, Kava, Ketamine, Kykeon, LSD, MDMA, Maikua, Manna, Nitrous Oxide, Peyote, Psilocybin Mushroom, Santa Rosa, Soma, Tobacco, Yaqona
"The available evidence suggests that manna was used sacramentally in ancient Israel in a straightforward manner. One ate the showbread and awaited the occurrence of a psychedelic experience. On the occasion of one's first experience, the person who supplied the showbread enacted the role of Yahveh and, once the psychedelic experience was underway, pronounced the name of Yahveh. In this manner, the experience was guided in a religious direction." 
Merkur finds (I think) convincing reference to and evidence for the use of Connection Supplements in the biblical story of Adam and Eve (Tree of Knowledge of Good and Evil), in New Testament use of the Eucharist in legends of the Holy Grail, in the writings of medieval mystics, in the Kabbalah, and in the writings of Philo of Alexandria.
There is a reference in 2 Esdras 14 to what appears to be a vision quest of five people, facilitated by some sort of psychoactive beverage. The vision quest led to increased wisdom and understanding, as well as forty days of creative activity wherein twenty-four books of divine revelation were created.
"So I took the five men, as he commanded me, and we proceeded to the field, and remained there. And on the next day, behold, a voice called me, saying, “Ezra, open your mouth and drink what I give you to drink.” Then I opened my mouth, and behold, a full cup was offered to me; it was full of something like water, but its color was like fire. And I took it and drank; and when I had drunk it, my heart poured forth understanding, and wisdom increased in my breast, for my spirit retained its memory; and my mouth was opened, and was no longer closed. And the Most High gave understanding to the five men, and by turns they wrote what was dictated, in characters which they did not know. They sat forty days, and wrote during the daytime, and ate their bread at night. As for me, I spoke in the daytime and was not silent at night. So during the forty days ninety-four books were written. And when the forty days were ended, the Most High spoke to me, saying, “Make public the twenty-four books that you wrote first and let the worthy and the unworthy read them; but keep the seventy that were written last, in order to give them to the wise among your people. For in them is the spring of understanding, the fountain of wisdom, and the river of knowledge.” And I did so."
It is very likely that Connection Supplements were used throughout the ancient Judaic and Christian world. It is also possible that these practices were eventually suppressed and replaced with rituals that "substituted psychologically inactive substances," i.e. the Catholic Eucharist, for the original Connection Supplements, as for example occurred when Catholic actors worked to suppress indigenous religious use of Peyote, claiming all sorts of absurd effects, especially in light of the growing body of research evidence indicating the salutatory/healing properties of connection supplements. We might also consider the Republican "War on Drugs" as a war against the powerful, healing, wisdom and life-giving properties of Connection Supplements.
- Merkur, Dan. The Mystery of Manna. Rochester, Vermont: Inner Traditions, 2000.
- Merkur, Dan. The Mystery of Manna. Rochester, Vermont: Inner Traditions, 2000. p. 26.
- Watermulder, Rev. G. A. “Mescal.” Lake Mohonk Conference on the Indian and Other Dependent Peoples. Mohonk Lake, N.Y., 1916 1914. https://babel.hathitrust.org/cgi/pt?id=coo.31924007333564&view=1up&seq=846. I encourage the reader to follow the link and read the entire, arrogant, dismissive, and racist "address."