We shall best comprehend the symptoms exhibited by fever by forming a correct picture of the processes of fermentation, as they may frequently be observed outside of the human body. For instance, if a bottle of freshly brewed beer be allowed to stand a few days, an alteration will be noticed in the fluid, which is generally designated by the term fermentation. This much we know of the process of fermentation: it is a decomposition, a sort of decay, during which, as already mentioned, little vegetable organisms called bacilli not only, as is often assumed, propagate themselves by reaching the fermenting mass from without and then spreading further; they are also regenerated by the transformation of the mass, thus being themselves only transformed matter, or a product of fermentation. Through the process of fermentation, or decomposition, the original mass is altered in form. Thus living bodies are produced from food and drink, transformed by the fermentative process of digestion. In this manner we naturally arrive at the conclusion—that all life is only a continual change under given conditions and that without the processes which I term fermentation, it could not be imagined at all.

The outward manifestations of fermentation are the following: first, the fermenting matter separating from the fluid is deposited on the bottom of the bottle. Now if the bottle is shaken, or a change in the temperature occurs, the deposit at the bottom begins to move and exhibits a tendency to spread. In spreading it moves upwards, and always in proportion to the amount of fermented matter deposited at the bottom and the temperature.

Let us look more closely into the cause of fermentation. Everybody knows that wine and beer are bottled and put in a cellar to prevent fermentation as far as possible. The cellar temperature is pretty much the same both in winter and in summer; no sudden changes of temperature occur, so that the chief cause of a quick fermentation is wanting. Likewise in the human organism fermentation takes place more quickly in warm weather.

We perceive how in the south and the tropics various acute fevers are always breaking out, whereas in our cooler climes we find chronic diseases prevailing. This is particularly on account of the more rapid and greater changes of temperature in the hotter climates, where by day the thermometer stands at 100°F and at night at 40°F; whereas in our northern countries the difference between the day and night temperatures seldom exceeds 22°F and is often less. Fevers often occur with us in spring, the reason being that then we find the greatest differences in temperature. Some may find it strange that children especially should be subject to acute illnesses, the familiar children’s diseases, while later in life chronic forms of disease mainly prevail. The above-mentioned change of temperature is here aided by the greater vigour of the youthful organism, which is still so great that it needs but little or no exciting cause to stimulate the organism to make the vehement struggle for health, ie, by an acute disease to rid itself of the foreign matter.

Now the same phenomena which take place in the bottle are observable in the human body. Here, too, the fermenting matter accumulates in the lower part of the trunk, and is then set in motion by some change in the weather, external shock, or mental excitement. Here, too, the movement is upwards; the fermenting substances have a tendency to spread and press against the skin covering the body. As long as the skin remains impervious, the pressure meets with resistance. Thus friction arises and consequently heat is developed. This is the explanation of the well-known fever-heat.

In the same way, it is easy to explain why a person in a feverish state has a somewhat greater circumference of body than usual—for the skin, being elastic, yields to the pressure of the fermenting matter, and the greater the pressure, the greater the tension of the skin. When the skin has reached its extreme tension, so that it can yield no further, the fever is at its height and the danger the greatest. For as the fermenting masses still have a tendency to expand and are unable to escape to the outside, they make room for themselves inside. The body may be said to inwardly burn and death is the unavoidable result—of course, only if the skin remains impervious. If we succeed in opening the outlets, the danger is removed, for then the fermenting matters find an exit, leaving the body in the form of perspiration. The interior of the body is now relieved and the heat and tension of the skin immediately subside.

No words are needed to show that the comparison between the human body encumbered with fermenting matter and a bottle filled with such, does not accord in every point. In the bottle, fermentation has free vent, the matter can expand in all directions without resistance, until it reaches the surrounding sides. In the human body, it meets with impediments everywhere. Every organ opposes its progress and hinders its course. Then it presses, pushes, and rubs against the obstructive organ, thus producing heat in it and even destroying it; if no outlet be made, or its course diverted. According to the part principally affected, the disease is said to be one of stomach, lungs, liver, heart, etc. But the part affected in each individual case depends upon the course taken by the fermenting matter, and this course again, upon the place and manner of the deposits.

Before the heat begins, we always notice, for days, weeks, or even months previously, a symptom, apparently the exact opposite of that described—there is a feeling of chilliness. The explanation of this is very simple. It arises as soon as the deposits have grown so considerable, that the blood can no longer circulate properly in the extremes of the body, but it, so to say, compressed all the more in the inner parts, so that great heat arises there.

Matter continues to be deposited—the time varying according to the particular patient—until one of the causes already mentioned occurs, thus causing fermentation to set in. The deposited matter causes disturbance in the circulation and alimentation. The blood vessels become partially obstructed, especially in their minutest branches, so that the blood can no longer reach the outer skin. This is the cause of cold feet and hands and of a chilly feeling all over. Chilliness is therefore a precursor of fever and we should make a grave mistake were we to leave it unnoticed. If proper treatment be immediately applied the fever cannot fully develop, but is, so to say, nipped in the bud.

When speaking before of the nature of fermentation, I remarked that in all fermentation little vegetable organisms, called bacilli, develop spontaneously. This is the case with fever, and thus the much debated bacillus question finds a simple solution. Whenever the matter which has settled in the abdomen begins to ferment, bacilli develop of themselves in the system; they are the product of fermentation, and likewise disappear of themselves when fermentation ceases and the system is restored to health, ie, when the process of fermentation retrogresses.

It is therefore idle to speak of infection through bacilli in some mysterious manner without the presence of foreign matter in the system. The question is how not to kill the bacilli, but rather how to remove the cause of fermentation, the foreign matter. This done, these little monsters which have caused terror to so many timid minds, vanish as a matter of course.

A few simple examples will more clearly illustrate my statements. Imagine a room left unswept and uncleaned for weeks, notwithstanding the much dirt that collects daily. Very soon vermin of all descriptions will take possession of the room and prove so troublesome to the inmates that every means will be tried to extirpate them. Now, if we attempt to destroy the vermin in the old-fashioned way by poison, we shall doubtless kill a large number, but by no means affect an alteration in the state of affairs; for the dirt itself is the actual producer and promoter of the vermin and will continually breed fresh swarms. But we shall attain quite a different result if we immediately cleanse the room of all filth; and by continuing this process we shall deprive the vermin of their proper elements and get rid of them for good and all.

Another example: imagine the swampy edge of a forest in summer. You all know what an annoyance the mosquitoes are in such a place. It will be evident to you all that it would be no good using poison to destroy them. True, hundreds of thousands would be killed, but millions upon millions would constantly issue from the swamp. The swamp itself is the breeding ground of the little ferments, consequently one must do away with it before the mosquitoes can be annihilated. We know that on dry heights hardly any mosquitoes exist. Were one to collect a great amount of them and carry them up such a mountain, with the intention of keeping them there, one would soon perceive these insects so laboriously transported, flying back to their native swamps, the dry mountain height being no suitable place for them.

A third example will render another matter still clearer. You are all well aware that the tropics, where by reason of the greater heat, there is a far greater diversification and development to be found in the animal kingdom than in the temperate and frigid zones, Nature gives birth to the most important and largest number of carnivora and carrion feeding animals. Whatever pains might be taken to exterminate them, new generations will always arise to take the place of those killed. Thus you see that these animals flourish only where, by reason of the greater development of life, there is also more putrefaction. If no relief were at hand, the dead animals would quickly poison the air with their putrescence, and render it unfit for the living ones. It is now plain why the principal animals which live upon flesh and carrion have their home in the tropics and not the extreme north, where the reindeer which live on grass and moss can hardly exist.

If therefore we should want to exterminate the carnivora and carrion feeders of the tropics, we should succeed only by removing the conditions of their existence, that is, the swarms of other animals there present; the beasts of prey would then disappear of themselves. All other means would be useless. But the smaller the animals are, the more difficult is their extermination; and of this the bacilli off the most striking example. In order to exterminate them it is of no avail to employ medicaments to poison them; we can only attain their end by removing the cause of their existence, that is, by expelling foreign matter from the body.

In these examples I have shown how Nature acts on a large scale, for all her laws are uniform. Nor does she admit exceptions in the case of disease. Precisely as do the vermin, mosquitoes, carnivora, and carrion feeders appear, live, and thrive only where they can find favourable conditions, so can fever not exist without such conditions, that is it cannot exist unless the system is encumbered with foreign matter. It is only when such matter is present, as we have seen, that by some cause fermentation can arise, which process we call fever.

But when we once know what fever is, it is not difficult to find a remedy. The closed up pores of the skin, against which the fermenting masses press, must be opened, and this can only be done by making the body perspire.

The instant the sweat breaks out, the fermenting masses gain a vent, and the tension of the skin and febrile heat both abate.

But with perspiration, the cause of the disease has not yet been removed. For the fermentation in any given case affects only a part of the matter deposited in the body; the rest remaining undisturbed is continually being increased by new accumulations, and thus forms an aver-present source of fever, which merely awaits a suitable occasion to break out afresh. Our aim must therefore be to bring about the expulsion of the matter still lying quiescent in the body. For this purpose I have introduced the friction hip and sitz baths by the aid of which the system is excited to expel the morbid matter from the body.

At the same time everything must be avoided which may disturb the body in its work. The patient must have ample rest, eg, he must not be excited by being read to or by conversation. Even the noise of the traffic on the street is injurious, and the chamber should be kept somewhat darkened; also at night, it should not be illuminated. There must be free access of air, however.

Not until there has been sufficient expulsion of foreign matter is the cause of the fever removed and thus the illness itself cured.

Let us now briefly review the foregoing, in order to deduce some important final conclusions.

In the case of all sick persons, alterations in the shape of the body are perceptible. These alterations are produced by foreign matter. The presence of such foreign matter in the body is disease. This matter consists of substances of which the body has no need, and which remain in it because of defective digestion. The foreign matter is first deposited in the neighbourhood of the secretory organs, but gradually spreads, especially where fermentation sets in, over the whole body. As long as the organs of secretion continue to expel a part of the foreign matter, the physical condition is endurable, but whenever their activity becomes lessened, the greater disturbances arise. The accumulation of foreign matter is not painful, being, so to speak, a latent or chronic process, which goes on unnoticed for a considerable period.

We can best designate the forms of disease resulting from such accumulation as painless and hidden; they are essentially the same as those generally called chronic or lingering.

The foreign matter is liable to decomposition; it is the real cause of fermentation and forms the soil on which bacilli can develop. Fermentation begins in the abdomen, where most foreign matter lies, but rapidly spreads upwards. The patient’s condition changes, pain is felt and fever sets in. These forms of disease we may term painful inflammatory diseases; they are otherwise termed as acute.

From the foregoing exposition we must now draw the momentous conclusion: there is only one cause of disease, and there is only one disease, which shows itself under different forms. We therefore ought not, strictly speaking, to distinguish between different forms of disease. It may be remarked in passing that different injuries, which are not really diseases in the above sense, are not here included.

It is therefore the doctrine of the Unity of Disease which I teach and defend, on the basis of the observations laid down in the foregoing.

I have now indicated the way in which I arrived at the conviction—a bold one, as many may think—that there is only one disease.

Through observation and inference, we have thus arrived at a statement which is of fundamental importance for the treatment of the sick. But I am able to prove its correctness by facts.

In modern science there is one kind of proof which is preferred to all others, and regarded as almost the only convincing one, and that is experimental. In the case in question, the experiment could be carried out only by the similar treatment of all kinds of diseases, when, if our statement is correct, uniformly successful cures must be the result. This proof I have given and continue to give. In the reports of cures, contained in the Appendix to my book, The New Science of Healing, you will find the results summarised.