Why Do We Lose the Sense of Smell When We Have a Cold?
The sense of smell depends upon tiny particles of things coming in the air to the lining of our noses, especially certain parts of the lining of the nose. When we have a cold, this lining, or mucous membrane, of the nose gets swollen, and produces a much greater amount of mucus than usual, as we all can tell by the number of handkerchiefs we have to use in a day.
The chief reason why we can not smell so well when we have a cold is probably that this mucous, constantly pouring out of the lining of the nose and running over it, prevents the scent of things from getting to the sensitive part of the nose, and washes away any solid scented particles. Also, it may be that the poisons produced by the microbes that cause a cold poison the living cells of the mucous membrane and also poison the tiny ends of the nerves of smell that run to it, so that, even if scented things do reach the sensitive part of the mucous membrane, they can not be felt.
This applies alike to scents coming in from outside and also to the scents of food, which pass up at the back of the roof of the mouth into the nose, and which, when we have not a cold, help to give our food half its flavor.
