Roger Povilus, age 12, of Omaha, Nebr., for his question;‑
How do we smell?
The five sense organs bring in a constant stream of information to the brain. The eyes carry pictures from near and far, the ears carry sounds. The skin is an organ of touch. The sense of taste makes eating a pleasure and even helps to digest our food. Sometimes the sense of smell works with the sense of taste to give us information about the also chemical nature of our food. The sense of smell/can warn of danger, escaping gas or a dead rat in the cellar. But its main job is to add to the joy of living. It brings us the smell of sage and warm sandstone from the prairies, the fresh fragrance of piny woods, the tangy tingle of salt spray on the beach.
The scientific word for smell is olfactory and this word crops up in the names of the various parts of the organs of smell. The olfactory organ is a pair of nerve systems between the nose and the front of the brain, The olfactory nerve endings are high in the nostrils. They collect information from the outside world and send it along nerve cables to the olfactory lobes in the brain. The brain translates this chemical information and tells us whether the new smell in the wind is a rose or a skunk.
The chemical information, of course, comes from the air and the air is a great thief. It steals tiny particles from almost everything it touches. Flower perfume and the liquid from a cut onion evaporate and mingle with the gaseous molecules of the air. Fragments of smoke and hosts of other tiny motes also are whisked off in the air.
The air, carrying its assortment of chemical particles and fragments, is drawn up the nostrils. At the very top of the nostrils 3t pass©a over a small bed of tiny, hairlike nerve endings called cilia.
These olfactory nerve endings are buried in the mucous membrane, the dewy, moist skin that lines the nostrils. Here the assorted chemicals are dissolved and the liquid stimulates the sensitive nerve endings.
We are not sure how many different odors the nerves can detect or how various odors are assembled to form blends. This complicated information is flashed along nerve cables to olfactory lobes. These are bulbs of nerve tissue, one on either side at the front of the brain. The brain uses its own miraculous system of sifting and sorting to tell us in a flash if the chemical information from the olfactory nerve endings is a fire warning or an invitation to a cook‑out.
The sensitive nerve endings can smell an onion when there is but one part of onion odor to a million parts of air. They do more to help you enjoy a cup of coffee than do the taste buds in your tongue. Some smells, however, are more acute and cancel out others. Gardenia, for example, will cancel out the smell of orange blossom. New smells are more noticeable because the nerve endings tend to tire, which explains why we tend to get used to an old smell and fail to notice