Stimulation of the olfactory epithelium with odorants in gaseous and aqueous phases

The olfactory epithelia of the bullfrog and the carp were stimulated with various odorants in the gaseous and/or aqueous phases. Some ionic solutions were also applied. 1. By recording the induced waves in the olfactory bulb, it was shown that the bullfrog responds to odorants in the two phases, but the carp can respond only to odorants in the aqueous phase. 2. Comparison of the stimulative effects of the same odorants in the two phases were made in the bullfrog. Although various response patterns to gaseous and aqueous stimuli of single cells in the olfactory bulb were found in most cases, a difference in the application methods of vapors and solutions made such comparison difficult. 3. The same single cells in the olfactory bulb usually responded to various odorous vapors and solutions as well as to ions in different patterns. When the responses to the vapors and solutions of the same odorants of different concentrations were compared, different patterns were also found.