How Can We Smell Things?
You do not need to be told what organ of the body we use in exercising the sense of smell. You can prove that easily to yourself by getting the nose within range of a distasteful smell.
We do not use all of the nose to smell with, and the nose is useful to us in other ways besides this. We use the nose a great deal in the act of respiration or breathing, and it is also useful in helping us to make sounds, form words, and, though you may not have known it, helps our sense of taste.
We smell things by means of the olfactory nerves which are located within the nose. The entire interior surface of the nose is covered with a membrane. The ends of olfactory nerves, or the nerves which give us the sensation of smell, are in this membrane, and the air, which is filled with the odor of things we smell, passes over this membrane, and thus the ends of the nerves feel the odor and cause sensation of smell in the brain. The nerves of smell do not, however, go all through this membrane.
There are other nerves in the nose, however, besides those which give us the sensation of smell. These are also very sensitive and serve to make the nose exercise other functions when the inside of the nose is hurt or tickled. When a foreign substance, one of the many smaller particles which are constantly floating in the air, gets into the membrane in the nose, it irritates these nerves and often causes us to sneeze, which is only nature’s effort to drive out this foreign substance and clean out the nose. Smell is one of the lesser of the five senses which we possess. It is one of what has been called the chemical senses. The sense of smell does not act at any great distance. This sense could be made of more value to us if we developed it. Some people have a more highly developed sense of smell than others. The lower animals have a much keener sense of smell than people. A great many of them can follow a trail for miles merely by the smell of the foot-prints, and it is said that a deer will note the presence of man or any other animal that may subject him to danger even when miles away, the odor being carried to him through the air.