Page:Eleanor Gamble - The Applicability of Weber's Law to Smell.pdf/6



By  ,, Ph. D., Cornell University.

CONTENTS.

Progress of the Experimental Proof of Weber's Law. Object and Scope of this Paper. Its connection with Zwaardemaker's Olfactometric Work. Zwaardemaker's Terminology. Defect of All Psychophysical Measurements. The Peculiar Difficulty of Olfactometry, viz., the Indeterminateness of Olfactory Qualities. Zwaardemaker's Classification of Olfactory Qualities. Antecedent Probability of the Applicability of Weber's Law to Smell.

I.

Section 1. Factors which Determine the Intensity of the Smell-Stimulus for the Normal Organ. (I.) The Quantity of Vapor Thrown Off by the Odorous Body. (II.) The Rate of Diffusion of the Odorous Vapor. (III.) The Rate and Manner of Breathing. Compensation of Smells. Direct and Indirect Olfactometric Methods. Methods of Valentin, Fischer and Penzoldt, Dibbits, Ottolenghi, Passy, Frölich, Aronsohn, Savelieff. Section 2. Control in Zwaardemaker's Olfactometric Method of the Factors which Determine the Intensity of the Stimulus. Treatment of the Two Factors of the Genetic Unit. The Method of Henry. Adhesion to the Inhaling-Tube. Control of the Diffusion-Rate of the Vapor. Control of the Manner and Rate of Breathing. Section 3. Anosmia and Hyperosmia. Method of Testing the Openness of the Nasal Passages. The Effect of Exhaustion. Section 4. Psychophysical Methods Employed. An Imperfect Method of Finding the Stimulus-Limen. The Method of Just Noticeable Differences. Intervals between Stimuli and between Determinations. The Method of Minimal Changes. A Modified Form of the Method of Just Noticeable Differences. The Subject's Tendency to Judge in Terms of Hand-Movement. The Method of Right and Wrong Cases. Chapter II. Apparatus and Materials. Section 1. The Standard and the Fluid-Mantle Olfactometers. (I.) The Standard Olfactometer. (II.) The Fluid-Mantle Olfactometer. Section 2. Preparation of Odorous Materials.