|Thomas Beddoes publishes Considerations on the Medical Use and on the Production of Factitious Airs, considered to be the first text on inhalation therapy in medicine 1
|Henry Hickman shows that a dog exposed to an atmosphere containing CO2 becomes anesthetized to pain 2
|Sir James Simpson writes Carbon dioxide is recognized by toxicologists as a very powerful narcotic poison when inhaled in sufficient qualities. 2
|Paul Bert shows when CO2 content of arterial blood is high, animals are anesthetized and unconscious 2
|Benedicenti finds that 10-15 CO2 is narcotic in animals, but 30 is needed to induce rapid unconsciousness 2
|A journal article describing the successful interruption of epileptic seizures with carbogen gas is published by W. G. Lennox. 2
|C. D. Leake and R. M. Waters find that 40 or higher CO2 concentrations cause interruptions to respiration and circulation 2
|A. S. Lovenhart, W. P. Lorenz, and R. M. Waters find that 30-40 CO2 mixtures induce moments of lucidity in catatonic patients 2
|CO2 co-administered with barbiturates is shown to cause death in animals, whereas the sedative paraldehyde appears to block CO2's toxic effects
|E. W. Brown finds humans can tolerate 10 CO2 for more than 10 minutes without losing consciousness, but that is the maximum concentration that does not cause unconsciousness 2
|M. De Almeida hypothesizes that carbon dioxide’s action on the brain is not the result of changes to blood pH 2
|R. Lorente de No publishes "A Study of Nerve Psychology", arguing that carbon dioxide affects the brain by altering the way neurons metabolize oxygen.
|Carbon Dioxide Therapy, L. J. Meduna's seminal monograph on psychiatric applications of carbogen, is published. 2
|Meduna and colleagues incorporate the Carbon Dioxide Research Association, which will eventually include hundreds of physicians in its rolls.
|Al Hubbard begins widely disseminating LSD and frequently uses carbogen as an "acid test" to see how people would respond to longer-lasting nonordinary states of consciousness. 3
|Aldous Huxley writes of Meduna's work in an appendix to "Heaven and Hell", an essay on entheogens. Huxley hypothesizes that spiritual practices involving the breath, such as chanting, induce religious visions through altering CO2 concentrations in the blood.
|Meduna publishes a greatly-expanded second edition of Carbon Dioxide Therapy, including papers by other researchers in the Carbon Dioxide Research Association.
|Hubbard introduces Myron Stolaroff to psychoactive substances with carbogen. Stolaroff responds with enthusiasm. 4
|Stolaroff founds the International Foundation for Advanced Study in Menlo Park as a research facility for the study of psychedelic substances. Carbogen is frequently administered, sometimes in combination with other substances. 4 [Details]
|Several studies are published documenting the use of a 95% oxygen/5% carbon dioxide mixture of carbogen to facilitate chemotherapy
|Erowid publishes a history of carbogen and a description of modern experiments with carbogen. 5