The Reason Why / A Careful Collection of Many Hundreds of Reasons for Things Which, Though Generally Believed, Are Imperfectly Understood

by Robert Kemp Philp

Fig. 66.—SHOWING THE DISTRIBUTION OF THE NERVOUS FILAMENTS UPON SENSITIVE MEMBRANES.

A. The olfactory nerve, distributed in minute branches upon the membrane of the nostril.

B. The bulb of the olfactory nerve.

C. The roots from which the olfactory nerve originates.

D E. Nerves of the palate, showing the manner in which they are passed through the bones of the roof of the mouth.

993. Why do hairs grow across the passages of the nostrils?

Because they form a defence against the admission of dust and insects, which would otherwise frequently irritate the nervous structure of the nose.

994. Why are the nostrils directed downwards?

Because, as odours and effluvia ascend, the nose is directed towards them, and thereby receives the readiest intimation of those bodies floating in the air which may be pleasurable to the sense, or offensive to the smell, and injurious to life.