September 10, 2005. At the International Association for Cannabis as Medicine 3rd Conference, held in Leiden, Holland, Mr. Hector Vizoso, study coordinator for Dr. Donald Abrams' study of smoking v. vaporizing, discussed the results of their clinical trial in humans comparing cannabinoid blood levels, carbon monoxide levels, and subjective effects in subjects who smoke and at other times vaporize marijuana (with the Volcano vaporizer). When subjects used vaporizers, the study found reductions in blood carbon monoxide levels as compared to smoking. In addition, the study showed that the vaporizer produced reliable levels of cannabinoids. The study also found that more subjects preferred vaporizing over smoking. This study was funded by a grant of about $136,000 from the Center for Medicinal Cannabis Research (CMCR). MAPS and CaNORML contributed an additional $100,000 on preliminary laboratory data analyzing the content of the vapors produced by the Volcano vaporizer.