Popular Education / For the use of Parents and Teachers, and for Young Persons of Both Sexes

by Ira Mayhew

This sense was given to men and animals to guide them in the selection of their food, and to enable them to guard against the use of articles that would be injurious if introduced into the stomach. In the inferior animals, the sense of taste still answers the original design of its bestowment; but in man, it has been abused and perverted by the use of artificial stimulants, which have created an acquired taste that, in most persons, is very detrimental to health. This sense is so modified by habit, that, not unfrequently, articles which were at first exceedingly offensive, become, at length, highly agreeable. It is in this manner that many persons, whose sense of taste has been impaired or perverted, have formed the disgusting and ruinous habits of smoking and chewing tobacco, and of using stimulating and intoxicating drinks. But these pernicious habits, and all similar indulgences, lessen the sensibility of the gustatory nerve, and ultimately destroy the natural relish for healthful food and drink. By this means, also, the digestive powers become disordered, and the general health is materially impaired. All persons, then, should seek to preserve the natural integrity of this sense, and to restore it immediately to healthy action when at all depraved, for upon this depends much of health and longevity, of happiness and usefulness.

This sense may be rendered very acute by cultivation, as is illustrated by persons who are accustomed to taste medicines, liquors, teas, etc. It ought, however, to be chiefly exercised in partaking of those simple articles of food and drink which are most conducive to health. In its natural state it prefers these, and if depraved it will soon recover a healthy tone, if not continually tempted by stimulating substances. This is beautifully illustrated in thousands of instances all over our country by persons who were once accustomed to use strong drink, but who have substituted for it sparkling water, a beverage prepared by God himself to nourish and invigorate his creatures, and beautify his footstool.

The Sense of Smell.—The sense of taste has received a faithful companion in that of smell. The beneficent Creator, with that wisdom which characterizes all his works, has very wisely placed the organ of this sense just above the mouth, in order that the scent of many things that are hurtful may warn us from partaking of them before they reach the mouth. The air-passages of the nose, in which this sense is located, are lined with a thin skin, called the mucous membrane, which is continuous with the lining membrane of the parts of the throat and of the external skin. Upon this membrane the olfactory nerve ramifies. The odoriferous particles of matter that float in the air come in contact with these fine and sensitive nerves as the air rushes through the nostrils, and the impression is conveyed to the brain by the olfactory nerve. The mucous membrane, upon which this ramifies, is of considerable extent in man. In the lower animals it is less or more extensive, according to the degree of acuteness of this sense. This membrane is full of little glands that are continually giving off thick mucus, and especially when the membrane is inflamed. There is a small canal leading from the eyes to the nose, through which a fluid, that also forms tears, is constantly passing when the passage is clear. It is the office of this fluid to moisten and thin the mucus of the nose. When this mucous is too abundant, as in some stages of a cold, and especially if it becomes dry from the closing of the canal leading from the eyes, or from any other cause, as fever, the sense of smell will be greatly impaired, if not entirely suspended. It is, indeed, not unfrequently permanently injured in this way, and sometimes is irrecoverably lost.

The sensation of smell, it should be borne in mind, is produced by a kind of odoriferous vapor, very fine and invisible, that flies off from nearly all bodies. The air which contains this vapor is drawn into the nose, and is in this way brought into contact with the very delicate nerves of smell that ramify the membrane which lines the air-passages of this organ. It is only when the exceedingly small particles of which the odor of various bodies is composed come in contact with the minute ramifications of the olfactory nerve that this sensation is produced. In order to protect these sensitive nerves, as well as to prevent the introduction into the lungs of injurious substances, the air-passages of the nose are furnished with hairy appendages, which are less or more abundant according to the size of these passages. These intercept any foreign substances that enter the nose, and thus irritate the mucous membrane, and cause a quick and powerful contraction of the diaphragm, by which the offending matter is immediately expelled. This phenomenon, which is called sneezing, depends upon a connection of the olfactory with the respiratory nerves.

This sense not only comes in to the aid of taste in enabling man and the lower animals to select proper food, and avoid that which is injurious, but it also gives us positive and varied pleasure by the inhalation of agreeable odors, while, at the same time, it enables us to avoid an infectious atmosphere, and all objects whose odors are offensive and hurtful.

It is true that man can accustom himself to nearly all kinds of odor, even to those that at first are very disagreeable. He indeed not unfrequently so vitiates the sense of smell as actually to prefer those scents which, to persons who have preserved the integrity of this sense, are regarded as exceedingly offensive, and even filthy. But why, let me ask, did the Creator give us the sense of smell? Was it to be thus perverted? No, indeed: it was, without doubt, that we might enjoy the refreshing fragrance of flowers and herbs, of food and drink; and also that we might distinguish between air that is pure and healthful, and that which is impure and infectious. As most articles of food which are agreeable to the smell are wholesome, and as those which are disagreeable are generally unwholesome, so, also, those states of the atmosphere which are grateful to this sense are salubrious, and those odors which are pleasant are healthful, while air which is ungrateful will generally be found injurious to health, as will also all those odors which are unpleasant to this sense when in a healthful state. He who has had occasion to enter a crowded court-room, lecture-room, church, or assembly-room of whatever kind, which has been occupied for a considerable time without adequate ventilation, can not fail to remember the unwelcome impression made upon his nasal organs when first he inhaled the vitiated atmosphere within, though by degrees he might have become accustomed to it, did he remain, so as ultimately to become well-nigh insensible to its noisome influence. But let such and all others be well assured that, however offensive such a fetid atmosphere may be to the smell, it is equally injurious to the health. And let those who, having returned from a morning walk or healthful exercise in a salubrious atmosphere, have had occasion to revisit the small and unventilated lodging-room in which they spent a restless night without refreshing sleep, perceive, in the sickening smell, a sufficient cause for all their pains and aches, and wonder how they survived such a gross violation of the organic laws.

All of the senses may be improved by education. The sense of smell constitutes no exception to this rule. Let none be discouraged, then; for the more we accustom our lungs and nasal organs to pure air, the more will they require it, and the more readily will they detect the presence of the least impurity.

This sense becomes very acute in deaf persons, and even more so in the case of those that are blind. The reason is obvious; for, as they are led of necessity to rely upon it more than persons who have all the senses, it becomes thereby developed, and is enabled more accurately to judge of the properties of whatever is submitted to its scrutiny. Seeing persons rarely partake of any article of food, and especially of any thing new, without first smelling it, and blind persons never; for this is the only means by which they can judge of its wholesomeness or unwholesomeness without tasting it.

Whatever stupefies the brain, impairs the healthy action of the nerve of smell, or thickens the membrane that lines the nasal cavities, and thus diminishes the sensibility of the nerves ramified upon it, injures this sense. All these effects are produced by the habitual use of snuff, which, when introduced into the nose, diminishes the sensibility of the nerves, and thickens the lining membrane. By its use the air-passages through the nostrils sometimes become completely obstructed. It is on this account that most habitual snuff-takers are compelled to open their mouths in order to breathe freely. It has been well said, that if Nature had intended that the nose should be used as a snuff-hole, she would doubtless have put it on the other end up.

The Sense of Hearing.—The external ear, although curiously shaped, is not the most important part of the organ whose function it is to take cognizance of sounds. In the transmission of sound to the brain, the vibrations of the air produced by the sonorous body are collected by the external ear, and conducted through the auditory canal to the drum of the ear, which is so arranged that it may be relaxed or tightened like the head of an ordinary drum. That its motion may be free, the air contained within the drum has free communication with the external air by an open passage, called the Eustachian tube, leading to the back of the mouth. This tube is sometimes obstructed by wax, when a degree of deafness ensues. But when the obstruction is removed in the effort of sneezing or otherwise, a crack or sudden noise is generally experienced, accompanied usually with an immediate return of acute hearing.