Again,

there is a part of the countenance that serves as a
passage for the breath, the 'nose'. For a man inhales and exhales by
this organ, and sneezing is effected by its means: which last is an
outward rush of collected breath, and is the only mode of breath
used as an omen and regarded as supernatural. Both inhalation and
exhalation go right on from the nose towards the chest; and with the
nostrils alone and separately it is impossible to inhale or exhale,
owing to the fact that the inspiration and respiration take place from
the chest along the windpipe, and not by any portion connected with
the head; and indeed it is possible for a creature to live without
using this process of nasal respiration.