. A text-book of physiology : for medical students and physicians . erhaps anatomically to therod and cone layer of theretina. The connections ofthese cells with the centralnervous system have al-ready been described (). It will be remem-bered that the fine, non-medullated fibers springingfrom the basal end of thesense cells enter the olfac-tory bulb and end in ter-minal arborizations in the olfactory glomeruli, where they make con-nections by contact with the dendrites of the mitral cells of thebulb. Through the axons of these mitral cells the impulses are con-ducted along the olfactory
. A text-book of physiology : for medical students and physicians . erhaps anatomically to therod and cone layer of theretina. The connections ofthese cells with the centralnervous system have al-ready been described (). It will be remem-bered that the fine, non-medullated fibers springingfrom the basal end of thesense cells enter the olfac-tory bulb and end in ter-minal arborizations in the olfactory glomeruli, where they make con-nections by contact with the dendrites of the mitral cells of thebulb. Through the axons of these mitral cells the impulses are con-ducted along the olfactory tract to their various terminations in theolfactory lobe itself, either of the same or of the opposite side, andeventually also in the cortical region, the uncinate gyrus of thehippocampal lobe. As regards the olfactory sense cells, the nervecells in the olfactory bulb might be compared with the nerve gan-glion layer of the retina, and the nerve fibers of the olfactory tractwith the fibers of the optic nerve. The Mechanism of Smelling.—Odoriferous substances to. Fig. 122.—Cells of the olfactory region (afterv. Brunn): a, a, Olfactory cells; b, b, epithelialcells; n, n, central process prolonged as an olfac-tory nerve fibril; I, I, nucleus; c, knob-like cleartermination of peripheral process; h, h, bunch ofolfactory hairs. SENSATIONS OF TASTE AND SMELL. 301 affect the olfactory cells must, of course, penetrate into the upperpart of the nasal chamber. This end is attained during inspiration,either by simple diffusion or by currents produced by the act ofsniffing. It may also happen by way of the posterior nares. Infact, the flavors of many foods, fruits, wine, etc., are olfactory ratherthan gustatory sensations. When such food is swallowed the poste-rior nares are shut off from the pharynx by the soft palate, but inthe expiration succeeding the swallow the odor of the food is con-veyed to the olfactory end-organ. Flavors are perceived, therefore,not during the act of swallowi
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