The design and operation of an improved olfactometer for behavioral and physiological investigation1

An improved olfactometer is described, and its range of application for the study of the olfaction in man is discussed. The apparatus is based on air dilution; an odorant is diluted in a constant-flowing stream of air. The odor-containing air flows to S, who is seated in an enclosed partition with his head in a Plexiglas hood. A visual signal system allows communication between E and S. Precision flowmeters, solenoid valves, one-way floats, and an automated control system permit E to select rapidly a large range of stimuli, stimulus concentrations, and trial lengths. The apparatus has been used in a variety of situations ranging from absolute threshold detection to adaptation and recovery.