Physiological parameters for rhesus monkey and beagle dog (collected from literature) were tested in inhalation experiments with Forane. (Since Forane does not undergo biotransformation, its uptake and distribution depend solely on physiologocal parameters and solubility). Forane and methylene chloride were used to demonstrate species differences in vapor solubility in tissues of man, rhesus monkeys, beagle dogs, and Wistar rats. The experiments were performed to determine the metabolic coefficients of methylene chloride in monkey and dog. Published data was used to determine the coefficients of methylene chloride in man. These coefficients were used to model chronic exposures.