A guide to the examination of the nose : with remarks on the diagnosis of diseases of the nasal cavities / by E. Cresswell Baber.

  • Baber, E. Cresswell.
Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: A guide to the examination of the nose : with remarks on the diagnosis of diseases of the nasal cavities / by E. Cresswell Baber. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    chap, i.] RESPIRATION AND SMELL. 20 tion takes place entirely through the nasal cavities, the mouth at the same time being closed. Here it is interesting to notice Ziem's remark that all animals breathe with their months shut.* During quiet nasal respiration the main current of air passes through the lower or respiratory channel, (see p. 18), some of the air becoming diffused into the olfactory region, as shown by our spontaneous recognition of strong smells. When it is desired to smell any sub- stance, the air containing the odoriferous particles is drawn more directly into the olfactory region by repeated short sharp inspirations, which we term sniffing. The effect of this proceeding is, in the first place, to create a vacuum in the naso-pharynx, which would naturally be replaced by a current of air passing through the lower or respiratory channel. Owing to the horizontal position of the external nostrils, however, the current of air enters in a vertical direction. The result of these two circumstances being, as Zuckerkandl points out, that the air in the nasal fossae assumes a diagonal direction, and thus enters both portions of the nasal cavity. During the process of sniffing, the vestibule becomes flattened from side to side from the pressure of the outer air on the lateral cartilages, rather than from any muscular action. In all probability this arrangement also favours the vertical direction of the current on entering the nostrils. We see, therefore, that the horizontal position of these open- ings has an important bearing on the mechanism of smell. The results occurring from a want of this * Monatsschriftf. Ohrenheilkunde, xiii., i. An exception occurs (e.g., in dogs) when the mouth is kept open to allow the tongue to serve as an organ of perspiration to equalise the tomperaturo of the body.