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The Common Cold
The Common Head Cold:
 Colds In General

 Anatomical Outlines

 Nose And Throat Functions

 Highways For The Invasion Of Disease

 Predisposing Causes

 Atmospheric Factors

 Colds And Micro-organisms

 Symptoms, Complications And Sequelae

 Principles Of Prevention

 Methods Of Prevention

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Highways For The Invasion Of Disease

( Originally Published Early 1900's )

To best appreciate the wonderfully constructed machinery of the body and to understand rightly the conditions of health and the causation of disease, it is necessary that man should be considered from a biological viewpoint.

The perfected organism of the human body is, in reality, the final product of nature's never-ceasing process of specialisation. Every animal organism is possessed with certain fundamental functions, including consciousness of its needs, the incorporation and assimilation of needed material into its own organism, and reproduction of its kind.

The lowest animal in the scale performs these functions no less than the most highly developed. The amoeba, for example, a simple one-celled animal, extends a portion of its body and seizes food that is nearby, and having no stomach eats with its entire body, and having no organs of reproduction, the entire cell divides for the formation of new ones.

As we ascend in the scale of development, we find that the organism is composed of a number of cells, and that their constituent units become differentiated one from another in structure and in function. In other words, just as people group together for the common good and organise a community, and just as it is found advantageous that certain persons in this community should engage in one kind of occupation or profession and others in others; so it is with the grouping of the cells to form the more highly developed living organism. The perfected human body must then really be considered as made up of myriads of unicellular beings, bound together for the good of the whole and dividing among themselves the various duties to be performed. A large group of cells for ex-ample have arranged themselves together to form a pouch, especially adapted to receive food and digest it; another group have become modified to the kind of cells especially fitted to perform the respiratory function, others become transferred into muscle cells and so on.

It is obvious, when we look upon the various organs of the body as so formed, that a very close relationship must exist between them, for the perfect working of the entire system is dependent upon the co-operation of the different parts. It is for this reason that disease in one organ is never limited to that organ, but is bound to produce disorder or ill health throughout the entire organism.

One of the important functions of a body politic is that it shall provide against the invasion of a foreign foe. Likewise with the great colony of cells forming the body. It was Metchnikoff who discovered that the little round white cells called leucocytes do police duty by catching and destroying the harmful bacteria which have gained entrance into the system.

But the policy of the cell as a sociologic organisation is to prevent invasion and as far as possible fortify against it. Accordingly, in harmony with her method. of specialisation, nature has made certain cells specially flat and tough, and then spread them out into a great layer covering the entire body and forming its skin.

Every man is therefore surrounded by a sort of Chinese wall, and so long as no break or cut is made affecting its integrity, it imposes a fairly reliable defence against the hordes of bacteria which everywhere surround us.

But a way must be provided for the entrance of food and air; for the body cannot exist independent of the outside world, and must extract therefrom material necessary to its sustenance, growth, and development.

The nose and throat may be regarded as open ports for the entrance of needed material, and as such necessarily are attended with the danger that at the same time there may come much that is undesirable and harmful.

The act of respiration is not only an absolutely indispensable function of the body, but it is one of constant activity. Now if the respiratory tract were nothing more than a mere tube for the purpose of carrying the air to and from the lungs it might have a hard impervious lining like that of the skin; but there are important functions to be performed beginning with the nose, and to perform these functions we find the entire tract must be lined with especially constructed cells forming a soft, yielding moist membrane, of extreme delicacy.

Just beneath this thin vulnerable membrane are numerous glands and a rich network of blood vessels, which might easily be affected by injury and disease, upsetting their functions and giving rise to infection.

Has nature entirely overlooked this dangerously exposed area, this natural avenue for the invasion of disease? By no means, for realising the special vulnerability of this quarter, she has erected unusual lines of defence to oppose invasion. I invite you to the consideration of the protective mechanism. It is interesting, as showing how nature works.

A knowledge of these lines of defence is more-over of the highest hygienic importance, because good health depends upon our maintaining their integrity, whereas, their impairment and disability will surely lead to serious consequences. I believe that a great many people, if you ask them what the function of the nose is, replying rather thoughtlessly, would say that it is the organ of smell. But as noted in Chapter III, the most important and vital function of the nose is that of respiration. The air must not enter the lungs in the crude state, but must be warmed, moistened, and purified. It must be deprived of the injurious dust and germs with which it is habitually loaded, and for this duty the interior of the nose is particularly adapted by reason of the peculiar character of the structure of its mucous membrane.

Olfaction is of secondary consideration and we may say that the smelling organ serves its main purpose in apprising the individual of things which it might be harmful for him to breathe or eat. In some of the lower animals the organ of olfaction is very highly developed and is almost their sole dependence in enabling them to protect themselves against things that are injurious and to select what is beneficial. Man too, would often do well to obey the warning given him by his olfactory sense, and not breathe an atmosphere, whose stale, fetid, or otherwise offensive odour indicates its unwholesome character. We must realise then that the olfactory function, while still preserving its primary protective purpose, so important to lower animals, lias become in man subsidiary to the more important function of respiration.

Nature's line of defence connected with the air passages begins just within the nostrils, in the part of the nose we call the vestibule. Here we always find a number of hairs or bristles, technically spoken of as the vibrissae.

Their purpose of course is to act as a sieve to entangle the dust and coarser particles of dirt, which would be deleterious to the respiratory mucous membrane. When injurious matter gets beyond the vestibule to the surface of the mucous membrane, other protective mechanisms come into play. The nasal passage instead of being a straight smooth tube directed backward, is in reality a more or less tortuous wedge-shaped cavity, divided by a median line into two similar halves.

Attached to the outer wall of each, as indicated in Chapter II, are three scroll-like bodies ex-tending from the front horizontally and covered with mucous membrane especially thick in places.

The construction is such, therefore, that it tends to slow up the current of air and cause it to break into eddies, thereby facilitating the deposit of foreign bodies, as well as serving more efficiently to warm and moisten the inspired air.

The extreme sensitiveness of the mucous membrane lining the nose is another guarantee of protection. Anything of an irritant character will produce an extra flow of secretions which tend to wash it out and, in some cases, will provoke the protective act of sneezing. This consists of a paroxysmal expiration of air, driven through the nasal passages with a great force and an accompanying excess of secretion destined to expel irritant foreign matter.

But, of all the protective mechanism of the air passages, the most wonderful and interesting and at the same time the most effective is one which operates noiselessly and invisibly.

To the naked eye the lining of the nose appears as a perfectly smooth membrane; but if we cut out a section and place it under a high power microscope, we would find it covered with fine hair-like appendages, called cilia, which when the membrane is intact and healthy are in constant motion. The motion of each little cilium may be likened to the crack of a whip; in case of the nose the quick action always being backward as though to whip secretions toward the opening in the mouth.

In these myriads of cilia, forming together a waving field of hairs, we have a protective mechanism in the nose of the highest value in preventing injurious matter from gaining entrance into the lungs, and it accordingly is of great importance that all forms of catarrhal inflammation which might hamper the fine working of this mechanism be corrected without delay.

The watery secretion of the nose must also be counted as a part of its defensive artillery. In the first place, by entangling and dissolving solid particles brought into the nose with the inspired air, it greatly facilitates the disposition of these substances. In the second place, the ciliated motion of which we have just spoken is favoured by the moisture and warmth of these secretions, and, thirdly, the serum itself is directly antagonistic to the bacteria of disease. It is disputed as to whether or not the nasal secretions have actual germicidal properties, but it is generally agreed that they are at least unsuitable to the activities of germ life and accordingly prevent bacteria from multiplying and becoming virulent.

So much for the splendid. fortifications of defence' which have been erected in the nasal thoroughfare. Has nature staked her all upon these barriers, confident that they are invincible, or has she stationed others beyond? Dotted here and there over the mucous membrane of the throat, we see little nodules or hillocks. In certain locations we see tissue of a similar appearance heaped together in rounded masses. What are these large rounded masses and these little disseminated hillocks? They have certainly a suspicious look, for they suggest scattered or massed field pieces, a defensive artillery of the throat.

The smaller ones are disseminated nodules of lymphatic tissue while the larger ones are precisely the same tissue heaped together to form tonsils. As shown above, there are four of these tonsils, not just two as most of you perhaps are in the habit of thinking.

On each side of the throat between the folds which pass downward from the palate are placed the chief tonsils. These are the faucial tonsils and are those which are always meant when one simply speaks of tonsils without qualifications. (Fig. 5.) Hidden up in the vault of the throat just back of the nose is another, the pharyngeal, or as it is called, the third tonsil. This organ is particularly active in childhood and when enlarged constitutes the so-called adenoids of which you hear so often. (Fig. 10.) We will speak of them later. The fourth tonsil is at the base of the tongue and known there-fore as the lingual tonsil; it is inflamed less often than the others, but may give so much trouble as to require removal. The sensation when it is enlarged is that of a ball in the throat, felt in the act of swallowing. The voice, especially the singing voice, is also often affected by the tonsils.

I know the question that is now in your mind and which you would like to ask me. If the tonsils are a part of nature's protection against disease, why do physicians almost universally recommend their removal? In answering this question, let me say that the tonsils are never to be removed simply because you have them. No physician should be guilty of recommending their removal, and no surgeon of performing the operation when those tonsils are seen to be normal, healthy, and capable of performing their functions.

No person should lose his tonsils without reason. But, unfortunately, a reason often exists. The truth is that the tonsils are seldom fully equal to the task which has been assigned to them. As barriers against disease they generally prove incompetent and go down with the first onslaught of the enemy. We need no further evidence of this than the microscope examinations which have frequently been made of the removed organ by ex-pert pathologists.

We find them generally teeming with bacteria and often riddled with disease. The lymphocytes, the particular cells of these lympathic structures which endeavour to put up a fight against the invading army are overwhelmed by hosts of little foes and then all is lost.

The tonsils now instead of being a bulwark of defence are just the reverse. The bacteria swarm in the crypts, convert healthy places into diseased and favour the formation of pus pockets. These pockets are cesspools of destruction, and recent investigations are proving more and more that herein lies a prolific source of many of the ills to which the flesh is heir. Toxins of all kinds produced by the various and more or less virulent bacteria in diseased tonsils, are constantly being absorbed into the system and infections of different kinds are the result.

Rheumatism and the allied disorders are now recognised as being of infectious character, chiefly due to toxins manufactured by the tonsils. Inflammation of the membranes of the heart (endocarditis and pericarditis) are infections which have been definitely traced to the same origin.

According to some authors even kidney inflammation can be due to toxins manufactured in a diseased tonsil.

However important might be the function of the tonsil when healthy, who would wish to keep an organ when it has become so diseased that it is not only incapable of its natural function, but on the contrary has become a Pandora box of infection and disease?

What we said of the faucial tonsils applies, though with modifications, to the others. The enlargement of the third tonsil constituting the so-called adenoids is attended with certain special evils due to its location. Situated as it is in the post-nasal space it cannot take on a considerable size without encroaching upon the posterior opening of nasal passages or upon the Eustachian tubes whose pharyngeal orifices are to be found on the two sides.

The Eustachian tubes are the ventilating shafts which pass from the ear to the throat. Any obstruction of these channels is a serious menace to the sense of hearing. If the obstruction persists, permanent impairment of hearing is to be feared. It is in children especially that these adenoids occur, and in them they are the chief causes of colds in the head. They are vulnerable structures, quickly and easily inflamed and tending to pass on the infection to neighbouring parts.

When the infection happens to travel up the Eustachian tube it is likely to produce an abscess in the middle ear; and the harm and dangers of a middle ear abscess would make a chapter in itself. Adenoid vegetations restrict nasal respiration and make of the unfortunate child an habitual mouth breather.

This brings us to say something of the general evils of nasal obstructions which may be caused not by adenoids alone but by various dis-eases, growths and malformations occurring within the nasal passage. We have referred to the important function of the nose in preparing the inspired air by warming, moistening, filtering and purifying it, so that it shall be fit to enter the sacred precincts of the lungs. When the cur-rent of air becomes deflected from its natural course and has to pass through the mouth, these important, vital functions are suspended, because the membranes of the throat are not competent to perform the same duties.

The mouth is, justly speaking, the gateway of the digestive tract, and is no more a proper pas-sage for air, than is the nose a proper passage for food. Indeed it can be said that it would hardly be less physiological to practice eating through the nose than to indulge regularly in the habit of breathing through the mouth. When the inspired air is deprived of the benefit of the nasal functions, it reaches the lungs in such an unfit condition that the process of the oxygenisation of the blood is very imperfectly performed. This accounts for the anemia and malnutrition from which mouth breathers are universally observed to suffer.

The whole respiratory tract below the nose suffers in consequence of mouth breathing. The air, attempting to get the moisture and warmth required, works havoc upon the membranes of the throat, making them dry, glazed and parched, and the constant deposit of dust and irritant sub-stances is certain to give rise to chronic catarrhal inflammation of the pharynx and tonsils, and also of the larynx, windpipe and bronchial tubes. These parts become naturally much less resistant, and are frequently the subject of colds, and it cannot be denied that the lungs in such a case are more likely to become a prey to tuberculosis.

Many people do not realise the importance of the respiratory act. Even a slight narrowing of the passages should be looked upon as a serious handicap, for when it is considered that one breathes at the rate of 26,000 times in 24 hours we must realise that the sum of the accumulated loss, however slight, will soon mount up to a great total.

In spite of a difficulty in getting sufficient air by way of the nose, one can generally practice nose breathing by an effort of the conscious will; but during sleep when the muscles are relaxed, it only requires a slight difficulty in the passage of air through the nose to make it take the easier way through the mouth. One may safely conclude that such is the case if he, regularly in the mornings upon waking, finds that his lips are parched, his tongue coated, and his throat feels dry and sticky.

We cannot stop now to describe or even enumerate the various conditions which may be responsible for nasal obstruction. The most frequent are nasal polyps, hypertrophy of the turbinai bodies, bony outgrowths from the septum and septal deviations.

Disease of the nose not of an obstructive character may give rise to grave disorders of the general system, no less than obstructive lesions. If, for example, there exists such an advanced catarrhal affection of these organs that the membranes are constantly covered with a thick tenacious secretion it is evident that even though the air may traverse the nasal passages unimpeded, the functions of the membranes will be just as much in abeyance, as if obstruction existed.

Catarrhal affections must be reckoned as more or less injurious to the general health in proportion as they subvert the normal nasal functions. Furthermore, most catarrhal troubles will tend to hamper the natural mechanism of defence, giving easier access to various sorts of infection.

It is generally believed that the micro-organisms of cerebrospinal meningitis find their way into the system through the nose, and there is reason to suspect that whooping cough, measles and scarlatina may originate in the same way. It has been estimated that fourteen thousand bacteria enter the respiratory tract with every breath, which would mean something like four hundred million in the course of 24 hours. Is it not rather a wonder that infection can be avoided at all, than a cause of surprise that it sometimes occurs?

As careful bacteriological examinations frequently have shown, the interior of the mouth and throat of even healthy persons regularly contains numerous bacteria most of them it is true benign, but some of them of a malignant type.

They will remain inactive as long as healthy local conditions prevail and the person's general resistance is kept at par. But let one be exposed to unfavourable weather conditions, such as will tend to produce a congestion of the nose and throat, and let the individual be at the same time in a general run down condition, how quickly a cold develops and these bacteria become active and virulent! Many of the infectious diseases of both childhood and adolescence have their beginning in the rousing to activity of the dormant bacterial flora of the nose and mouth.

Can one trust to antiseptic mouth washes, gargles, nasal douches, and sprays to keep the nose and throat free from germs and thus prevent colds and infections? No doubt they help in certain circumstances and when properly used, but to rely upon such measures solely and absolutely is faulty hygiene.

Antiseptic solutions may destroy the most superficially lying bacteria but they do not reach those which have penetrated the deeper layers and they do not correct the pathological alterations in the membranes themselves. There is indeed harm rather than good if the antiseptics used are of such character and concentration as to irritate the membranes, especially the delicate membrane of the nose, interfering with the natural processes of protection and repair.

We should not close the subject, without some reference to another subdivision of the upper respiratory tract, namely, the larynx. When we were discussing the functions of the nose, we emphasised the fact that the nose was not primarily an organ of olfaction but of respiration. Now in regard to the larynx or "voice box," it would be similarly putting the cart before the horse to say that the windpipe was placed in the throat primarily to subserve the purpose of a speaking organ.

Here again we should realise that breathing is the paramount function and the windpipe there-fore must, first of all, be regarded as a part of the respiratory tract. And just as nature could so nicely utilise the nasal passages as a location for the olfactory organ, so again what more appropriate place could be found than the windpipe for the location of the vocal instrument.

The lungs acting as a bellows furnish the necessary blast of air which, passing up the tube, can be so well utilised for throwing into vibration the little bands stretched across the tube at this point. These bands by the action of certain small muscles can be placed through the different degrees of approximation and tension appropriate for producing sounds of varying pitch.

We may not be able to go as far as to say with regard to the larynx as we did of the organ of smell that its purpose is primarily for protection in connection with the respiratory functions, but we will call your attention to the fact that nature has not failed to make use of the opportunity afforded to establish in the narrow path formed by the vocal cords, another means of defence.

The vocal cords not only are approximated or brought together for the purpose of speaking, but also for coughing, giving thereby greater expulsive force to the expiratory blast of air coming from the lungs. The coughing act is always excited by the intrusion into the lower passage of irritant foreign substances, for the driving out of which a cough is no less effective than in getting rid of diseased products or secretions formed within.

The spasm of the vocal cords, shutting off the breath and giving a sense of suffocation, which many of us have experienced when we have had the misfortune to swallow something the wrong way, is likewise a protective phenomenon. It is nothing more than a violent contraction of the muscles of the vocal cords, intended to prevent the entrance of harmful substances into the sensitive air passages below.

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