The Sense of Smell

IT is remarkable how intimate the sense of smell is, how much it tells us, and how largely it affects consciousness on the one hand, and how we scorn consideration of it on the other. It is the Cinderella of our organs of sense. Whether it was some sainted anchorite, or other enthusiast of imagination and influence, who found the use of the human nose to be dangerous to the soul, we do not know, but in some way or other the conscious exercise of the nose became taboo, and this has entered into the folk-ways. It has ceased to be a sin, but it remains an impolite subject.

The Arabs in their days of glory were not ashamed of their noses, and they planted scented gardens, wonderfully devised, so that he who walked through them, or whiled away an hour there, might rejoice in a cultured delight in odor. They were so arranged that at the entrance the olfactory sense would be struck by a pervading and strong smell, not necessarily of a pleasant nature. From this the path would lead gradually through less coarse fragrances to those more delicate until, at the end, there would be reached an odor of exquisite quality which only the cultured nose could appreciate.

Now, by the grace of editorial sanction, let us cast aside convention and talk about it. Every one of us has his or her own odor, as distinct and personal as are our countenances. Every dog knows this and, unless his olfactory organs are atrophied, he makes good use of it. We constantly exude products of metabolism, and in the composition of these products we all differ. Not only do we differ from each other, but in no individual are these products constant. No chemical laboratory is equipped to distinguish these minute differences, and, so far as the writer is aware, the subject is still unstudied — except by dogs. They, with their highly developed olfactory organs, are impelled by curiosity to confirm their vision when they meet their master, and they make a long and searching nose investigation of him, clearly with a view to finding out more than their eyes will tell them. We note, too, that dogs which follow the scent closely are likely occasionally to go into a mephitic debauch with a decayed fish or any other substance of similar pungency, to ‘clean their scent.’ That, after filling the nostrils with agony of that sort, they should find them in better working order is an idea that does not seem reasonable, and yet the method is probably a good one, for the same reason that the Arabs planted flowers of pungent and coarse odor at the entrances to their scented gardens.

The theory of smell as given is very vague; there is a presumable impact of particles upon the sensitive regions of the nose which, in some way, is supposed to stimulate nerve-reaction. Good work has been done, but not enough; and enough will not be done until there obtains a lively and wholesome curiosity about it.

On the other hand, consider what illuminating researches are available in regard to sound and light! As an instance of the comparative attention devoted to these subjects, one has but to open a book of reference such as, for instance, the Encyclopœdia Britannica. In the last edition of this work over twenty-two pages are devoted to sound, sixteen to light, and but a page and a half to smell.

Just think what we owe to our eyes and ears! Through them we gain nearly all of our knowledge. They are trained so that by them we read books and hear speeches, we note anger, deceit, joy, love; by sight and hearing we try to guess faithfulness and malice; in fact, through these two senses we draw the substance of our information. And yet we are said to have five senses. Neither touch nor hearing nor sight is within the scope of this paper,and taste is a limited sense, alive only to sweet, sour, bitter, and a few simple nerve-reactions. Owing to the taboo of smell we have credited to taste most of those olfactory processes which we have cultivated. It is the smell of good food that we enjoy while we are eating it; it is the bouquet of a wine that gives it its merit. We call it the taste, but it is chiefly the smell. It is nearly impossible, for instance, to distinguish between what we call the taste of cinnamon and that of cloves if we hold our noses.

So here is this organ, equipped for the acquisition of knowledge, as complex as the human eye, entering into the most active part of the brain, and we, marveling at the wonderful advances of human knowledge, neglect it, scorn it, politely deny that there even is such a thing as an individual odor to ourselves and our friends. We remain more ignorant than a dog about it. And yet, despite all this neglect, it is always active. This must be true, else it would not be such an aid to memory as it is.

I remember once, long ago, I employed a chemist to make a certain product that he had worked out in a factory under my charge. He demonstrated it in the laboratory and then proceeded, in the works, to prepare a few hundred pounds in some tanks and apparatus at hand. At this point it developed that the process was in conflict with certain patents, and that we could not continue without infringing upon rights of others that were already established. So the whole thing was given up and that was an end of it.

At the time I was intensely engaged in other problems, and aside from occasionally visiting the chemist while at work, I had but little to do with it. Shortly after that the works passed into other hands and I quitted the practice of chemistry and went into business. Ten years elapsed, during which time I had been out of practice and wholly out of the thought of the process in question. Then I was informed that a chemical manufacturer was anxious to see me in regard to some patent litigation in which he was engaged. I feared I could not help him; I said I had forgotten everything I knew, but that if he wanted to see me I should be glad to meet him. He explained his problem and asked me about that process. I could not remember a thing. He suggested that we go through his factory, which we did. ‘Hello’ I said; ‘here is some β naphthol! What lovely figures it makes! ’ And I dipped my fingers into the water in which it was in suspension and stirred it around, watching the shining scales. Then I removed my hand and smelled of my fingers. In an instant I shouted, ‘Now I remember that process!’ and proceeded to relate it to him in detail. β naphthol had been one of the materials used in it.

If, when you went to school as a child, you carried a tin lunch-box which often contained, let us say, some gingerbread and sandwiches and perhaps an apple, it is worth while to take a sniff at such a box again, now. It is surprising how this simple experiment may recall the patter of long-forgotten feet and the memory of childish voices that startle over the long lapse of years.

These flashes of memory aided by smell are wonderful. Through smell we achieve a sense of the past; the secret members of the mind are roused to life and memory. What a pity that we waste this talent!

Again, how often it occurs that we see a friend or acquaintance and exclaim, ‘How strange! I was thinking of you less than a minute ago.’ In point of fact we have probably smelled him. Smell may also be the reason why we like some people and dislike others. I may want to introduce some one to you because you have many interests in common and may tell each other things you both want to know. But as soon as you meet you will have none of him; you know he is honest, of good repute, and admirable in a thousand ways, but as for you, you are in great distress when he is around, and you are glad when he goes away. If you are of kindly disposition and fair-minded, you are probably annoyed with yourself for your prejudice; if you are a bumptious brother and selfish, you probably attribute some imaginary vice or evil to him by way of excusing yourself. In both instances it may be that you do not like the smell of him, although you do not know it. You see, we are so ignorant in our noses — more ignorant than savages or even animals; we are very low in the scale of intelligence in this respect, and we respond to the olfactory reactions unconsciously. Notwithstanding our crass ignorance, the noses are still there, and we all really do produce odors despite our frequent bathing. Varnishing the skin to close the openings of the sweat glands would be the only way to put a stop to individuality of odor, and this has never been recommended as an aid to cleanliness or to health.

Let us suppose the subject were not taboo and the good old Saxon word, stink, which bears about the same relation to odor that noise does to sound, were not almost unprintable — and suppose we really used our noses with consciousness and diligence. There would be Americas to discover, and life would be marvelously augmented! Of course, as soon as we begin to consider the subject we find ourselves wholly at sea. There are no standards. Out of the awful chaos in which we wallow we can possibly find a few intimations, but we cannot put them down as rules. Thus it would seem that, in watching the order of nature, the olfactory phenomena of creation or reproduction seem to be agreeable and hence desirable, and those of dissolution are likely to be disagreeable. So the flowers which precede the seed-time of plants are likely to produce in the nose a sense of pleasure. They attract bees and insects which are useful to the continuance of the species, but they attract us also, and the cause of our attraction is presumably the same. Ben Jonson, when he sang to his mistress of the rosy wreath which she sent him, that ‘it grows and smells, I swear, not of itself, but thee,’ knew what he was writing. It may be, indeed it is probable, that the close relation of smell to sex phenomena is what caused the taboo. But there is a spirit abroad nowadays to search the truth, with the growing belief that it is well for humanity to adjust itself to the demands of that spirit. The search for the truth, we are beginning to think, is a wholesome occupation.

That the phenomena of disintegration are unpleasant we know too well; in fact, we more than know it; we have made a convention of it. We almost blush in passing a barnyard, we are shocked at the coarseness of the Germans who say ‘ kuenstliche Duenger' for artificial fertilizers, and I have heard a skunk referred to as a ’little-black-and-white animal,’to avoid the inelegance of calling his odor to mind. Oh, we are exquisite! There’s no doubt of that, even if we are vastly ignorant. Refinements of this sort are of weight in aiding us to make vain distinctions between ourselves and those people whom we regard as vulgar and common, but they do not aid us in the search for wisdom.

Now, many of the processes of disintegration are unpleasant and they serve as warnings, but the best of us does not put his handkerchief to his eyes if he sees an unpleasant sight, or stop his ears and run away if he hears a cry of pain. The best of us listens to hear where the trouble is, and hastens to help if he can. But when we smell a disagreeable odor we usually get up and run away. It is all we know how to do. And every unpleasant odor is by no means a sign of danger or even of organic disintegration. Some entirely harmless products are dreadful beyond description in their odor, and, on the other hand, the aroma of prussic acid and a number of other virulent poisons is delightful.

But the field is far wider than these qualifications of pleasantness and unpleasantness, and we shall only baffle research if we wed ourselves to empirical rules before they have been tested out.

Sir William Ramsay, whose everyoung enthusiasm leads him into so many of the secret gardens of nature, has found a relation between odor and molecular weight, and J. B. Haycraft has pointed out what appears to be a cousinship of odors that accords with the periodic law; another notes that odorous substances seem to be readily oxidized, and Tyndall showed that many odorous vapors have a considerable power of absorbing heat. Some work has been done in German, French, and Italian laboratories to discover the nature of the phenomenon of smell, but very little that is definite has been brought out; only here and there a few facts; and nobody seems to want to know them.

And yet the scientific possibilities are very fascinating, even if they are bewildering. For instance, it appears that the sensitive region of either nostril is provided with a great number of olfactory nerve-cells embedded in the epithelium. The olfactory cells are also connected by nerves which extend to the brain. Well, what happens when we smell anything? The olfactory nervecells are surrounded by a liquid. What is the nature of that liquid? Do the particles which we assume to be the cause of olfactory phenomena dissolve in it? If they do — and here we pray thee, oh, great Arrhenius, come help us! —does dissociation take place, and are there smell ions? That is, do fractions of the molecules of those bodies that give odor dissociate themselves from the rest and ride in an electric stream to the nerves? What do they do when they get there?

Let us try again. The ends of the nerves must be covered with some sort of a membrane. Here is where osmosis may come in.

Somehow it would seem that the particles that produce the sensation of smell must get through those membranes at the ends of the nerves. If they do not get through, themselves, they must project something through; it cannot be a simple tapping, gentle tapping, at the nose’s door. That might produce sound or heat or even light, but can it produce smell? Let us agree that the process may be an osmotic one and that the particles glide through softly, gently; and, without claiming that it has any special bearing upon the subject, let us remember that a healthy dog’s nose is cold.

Having guessed that smell may be caused by an impact of smell ions upon the nerve termini, and having guessed again that the process may be an osmotic one, we may be troubled anew with the question as to that liquid that we think covers the termini of the olfactory nerves. Is it a colloidal solution? Now I begin to grow comfortable because I confess frankly that concerning colloids I am vastly uninformed; and in ignorance is easy guessing. The content of nerves is colloidal, and it is fair to presume that this liquid is. All of those albuminous physiological products are. So, if the liquid covering the nerve-ends is a colloidal solution, — meaning not a true solution in the usual sense, but indicating particles in suspension so minute that the whole behaves like a solution, — let us assume that the substances producing odor enter into this state, and so we may proceed to call the process colloidal. It may be both colloidal and osmotic, it may be — but we shall do better to call for help.

We are sorely in need of research along the olfactory line. We are still questioning as to the nature of electricity and what it is, but good men are working over it. With the phenomenon of smell we are still mediæval. Nobody knows, and many talk big. There is little progress to be made by vapid guessing outside of laboratories. But those of us who are inactive in research may be of use if we are only frank and talk about it enough to get it out of the taboo under which it has rested for a thousand years. Then, if we maintain a simple curiosity such as animates children and great men, there will come from laboratories one fact after another which has not been known before. Then, some day, some one with the Vision will arise and arrange the facts in their real order and so, suddenly, there will stand revealed the Truth! Thus, with the sense of smell added to the intelligent use of mankind, life will be greater and larger, and the boundaries of human knowledge will be moved back a span, and human understanding will take one more great step in advance toward the Infinite.

To return to the dog, he seems to know and to recognize certain emotions through his nose. He seems to recognize fear, and to have all sorts of fun with it. He appears also to recognize good-will, — although not always, as many of us can testify, — and he seems to know anger. Now, we know that nerve-reactions have at least a chemical accompaniment. Metabolism is often inhibited, the whole digestive process is frequently upset, and there is a fair possibility that the sweat glands are so modified by emotions that their processes are indicative of emotional reactions. The trained nose might recognize this. If we could only advance along this line until we could recognize anger and fear, and possibly even deceit, consider in what measure life would be augmented! It seems a far cry to imagine, in a court of law, the witness testifying with two or three good smellers sitting close by, to note his sweat-reactions; but it would be no more absurd than some of our courts to-day, with their far more misleading entanglements of legal procedure.

We talk of the value of publicity in regard to corporate affairs, but we have only for a minute to consider what an aid to morals trained noses would be by way of effecting publicity in the family. The mere suggestion unlocks the door to the trouble parlor; but then, no one would try to lock it if he and his household were proficient in the art of smelling. The defaulting cashier

would reek to the ceiling of worry as soon as he made his first false entry, and if the specific odors of anger and deceit were discovered so that they might be known immediately, we — but this is not a theological discourse and its purpose is not to describe Paradise.