Page:Eleanor Gamble - The Applicability of Weber's Law to Smell.pdf/16

12 sneezing-reflex is most easily excited in the anterior portion of the nasal cavities, Nagel's remark that Zwaardemaker's localization-theory leads to “irresolyable contradiction” is not quite clear, but he is certainly right in saying that the theory has no adequate basis. Aside from the lack of experimental evidence, the arrangement of the several zones is too fancifully neat to carry conviction with it ; but Zwaardemaker himself emphasizes the fact that the essential part of his theory is simply the arrangement of the operations of specific energies of smell corresponding more or less exactly to the classification of Linnæus on the olfactory mucous membrane in the order of these classes.

Before bringing these introductory remarks to a close, it may be noted that, aside from any experimental evidence which may be offered, it is probable that Weber's law does apply to such smells, mixed and unmixed, as we daily encounter. In the first place we have the analogy of several other modalities of sensation for believing that the law applies to simple olfactory qualities. In the second place it has never been proved that Weber's law applies merely to unmixed sensations. It has been, neither proved nor disproved for clangs, but many experiences of ordinary life would lead us to believe that it does apply to musical chords as wholes. Thus it may apply to smell-fusions as wholes, and approximately correct difference-determinations may be obtained for these wholes even while their character is gradually altering, Since, in the present state of our knowledge, no one can even pretend to be working with simple olfactory qualities, all difference-determinations in smell must proceed upon the assumption of this possibility. Experimental results must be the only decisive evidence for or against the theory, so that it is needless to discuss it farther in this place.

In the third place the distinction drawn by Passy between “insistent” and “intensive” smells, which is based upon a classification of smells in the popular mind and confirmed by other scientific men, is explained by the supposition that Weber's law applies to smell with different values of $Δr/r$ for different qualities. In Zwaardemaker's language, and in the ordinary language of this paper, the smaller the “minimum perceptible "’ of a substance, the more intense its odor. Passy uses a term, “pouvoir odorant,”—which we may translate “insisteney,”—for “intensity” in our sense. Hesays : “Tout le monde sent que le camphre, le citron, le benzine sont des odeurs