An Inquiry into the Logical Basis of the Germ Theory

The germ “theory:" a scientific foundation or a logical fallacy?

To those familiar with my work, it comes as no surprise that I take great interest in highlighting the forgotten voices from the formative years of germ “theory” and virology—those who examined the rise of these pseudoscientific fields with critical eyes. These individuals had front-row seats to history, and they witnessed firsthand the unscientific, contradictory foundations that shaped our modern beliefs about health, disease, and wellness. They recognized the manipulation by vested interests and warned against the manufactured acceptance of germ “theory” by a fearful, uninformed public. And they spoke out—attempting to avert what they foresaw as a grave disaster.

Amongst the earliest of these voices was the great French chemist Antoine Béchamp, a rival of Pasteur and proponent of the competing terrain theory. He astutely recognized how the public had been misled in the preface to his 1867 publication La Théorie du Microzyma (translation from Bechamp or Pasteur: A Lost Chapter in the History of Biology):

“The general public, however intelligent, are struck only by that which it takes little trouble to understand. They have been told that the interior of the body is something more or less like the contents of a vessel filled with wine, and that this interior is not injured – that we do not become ill, except when germs, originally created morbid, penetrate into it from without, and then become microbes.

The public do not know whether this is true; they do not even know what a microbe is, but they take it on the word of the master; they believe it because it is simple and easy to understand; they believe and they repeat that the microbe makes us ill without inquiring further, because they have not the leisure – nor, perhaps, the capacity – to probe to the depths that which they are asked to believe.”

Decades before germ “theory” reached mainstream dominance, American physician Dr. Edward P. Hurd raised concerns about its flawed logic. In his 1874 paper On the Germ Theory of Disease, Hurd questioned whether germs were truly the cause of disease rather than mere byproducts of it. He specifically criticized the fallacy of affirming the consequent—the mistaken belief that if cause A (a germ) is always found with effect B (a disease), then A must have caused B. Hurd pointed out that simply showing a germ is always present with a disease does not prove causation. To establish a valid causal link, one must introduce the germ into a healthy environment and observe whether the disease follows—something germ theorists had failed to do:

“There is no proof that all that have as yet been found are not accompaniments, or effects, and not causes of the diseased conditions with which they are found associated. Halber has not yet completed the cycle of proof necessary to establish tho causal nexus between one single disease and the micrococcus found witli that disease. He has relied exclusively on what logicians call the method of agreement—the method of difference he has not tried. It is of little account for him to show that the supposed cause A always exists with the disease B, and hence B is the effect of A. Into a preexisting set of circumstances where B does not exist he must introduce A and produce the disease. This he has not attempted, and hence his speculations are of little worth.”

Another outspoken critic was Lionel S. Beale, pioneer of the microscope for medicine, who warned in 1878 how speculative claims—like germs causing disease—can rapidly gain traction through repetition and institutional backing. A few “authorities” assert, others repeat, officials endorse, and suddenly the world believes what was never proven:

“It is curious to observe how very easily in these days an untenable doctrine may be forced into notoriety, and taught far and wide as if it were actually demonstrated truth. A few authorities perhaps in Germany graphically portray what they please to call the results of observations, and after marshalling before the reader certain facts and arguments, remark that the evidence is perfectly conclusive in favour, say, of the view that certain contagious diseases are due to microzymes. Papers, with "new observations," soon follow, and confirm the original statement in every particular. Pupils, friends, admirers, accept and diffuse the new doctrine. Abstracts and memoirs multiply, and the conclusions arrived at abroad are supported and promulgated here, under the patronage of a government official, and published in a blue book. Those unacquainted with the art and mystery of transforming arbitrary assertions into scientific conclusions are easily convinced that the whole scientific world is agreed upon this one question at any rate, while in point of fact the speculative and far-fetched arguments would not have withstood careful and intelligent examination.”

Renowned British surgeon Dr. Lawson Tait, considered the greatest abdominal surgeon of his time, openly dismissed the fear of germs, once stating he would prefer a mass of germs over a wet sponge during surgery. In the 1887 paper An Address on the Development of Surgery and the Germ Theory, he declared:

“Let me only say that the best of all proof of the fallacy of their assertions is the fact that every attempt to elevate the germ facts of putrefaction into a germ theory of disease has miserably failed, and has failed nowhere so conspicuously as when obtruded into the realms of the treatment of disease.”

In the 1894 paper A Criticism of the “Germ Theory of Disease,” Based on the Baconian Method, Dr. Tait wrote that the germ “theory” wasn’t a theory or even a hypothesis. It was just a jumble of facts—some true, many false— with no coherent explanation behind them. No working hypothesis. No actual theory. It was simply dogma:

“The germ theory of disease is not a theory at all. It is not even a hypothesis. It is a mere congeries of facts some truly stated, but mixed up with a far greater bulk inaccurately (indeed, untruly stated), upon which not even a working hypotheses has yet been suggested, far less a theory built.”

In 1913, Dr. Herbert Snow—a surgeon, medical writer, and cancer researcher—published the article The Germ Theory of Disease (which I reprinted with additional commentary here) in which he exposed the lack of scientific proof that any microbe causes disease. His opening remarks are scathing:

“The Germ Theory of Disease, so prominent in medical literature and practice, began with the efforts of the chemist Pasteur to apply to human, maladies—which, not being a doctor, he only knew academically—deductions drawn from the phenomenoa he had observed in fermentation. There has never been anything approaching scientific proof of the casual association of micro-organisms with disease; and in most instances wherein such an association has been pretended, there is abundant evidence emphatically contradicting that view. Yet most unfortunately this lame and defective theory has become the foundation of a very extensive system of quackery, in the prosecution of which millions of capital are embarked, and no expense spared to hoodwink the public with the more credulous members of the Medical Faculty. It may then not be out of place to survey, as fudicially as may be, the position in which the Germ Theory now stands; with the ill consequences very conspicuously resulting from its premature adoption as a proven axiom of Science.”

By the 1920s, cracks in the germ “theory” narrative were becoming harder to ignore. In Principles and Practice of Naturopathy (1925), Dr. E.W. Cordingley, M.D., N.D., A.M., observed that the germ “theory” of disease was weakening and due to be thrown away:

"Medical doctors are working on the germ theory of disease...But the germ theory is already weakening and is due for being thrown aside. Dr. Fraser of Canada and Dr. Powell of California have experimented with billions of germs of all varieties, but they have been unable to produce a single disease by the introduction of germs into human subjects. Dr. Waite tried for years to prove the germ theory, but he could not do so. During the World War an experiment was conducted at Gallop's Island Massachusetts, in which millions of influenza germs were injected into over one hundred men at the Government hospital, and no one got the flu. Germs are scavengers.”

Dr. Cordingley referenced the experiments of Dr. Thomas Powell and Dr. John B. Fraser, both of whom experimented on themselves and others with billions of pure cultures of the most “dangerous” germs of all varieties, and were unable to produce a single disease through these efforts.

Dr. Powell—who asserted he was in direct opposition to “the greatest delusion of the world’s history” and that “scientists of the world are at fault in their germ theories”—stated:

“Before going into the details of my experiments with the germs of virulent diseases. I want to preface my statements with the explanation that I do not declare the germs to be harmless in all cases. What I do say is that a person to whom the germs of a particular disease are likely to prove dangerous must have a predisposition towards that particular disease, such predisposition being either hereditory or acquired. Given a man or woman with no such predisposition, and I claim that the deadliest germs are powerless to harm them. They can enter the sick chamber without fear of contracting disease, or even do as I have done, take the living germ into their system and suffer no harm. My experiments have proved the truth of my theory. “I claim that disease germs are utterly incapable of successfully assailing the tissues of the living body; that they are the results and not the cause of disease; that they are not in the least inimical to the life or health of the body; that, on the contrary, it is their peculiar function to rescue the living organism, whether of man or beast, from impending injury or destruction. They accomplish this by bringing about the decomposition of that obstructing matter which constitutes predisposition to disease, and cause it to be passed out by tlie blood.”

Dr. Fraser, through his experiments a few decades later, came to a similar conclusion: germs were the result of, and not the cause of, disease:

“If you examine the standard works on bacteriology you find no positive proofs given, that germs, if taken in food or drink, are harmful.”

“The assumptions that because germs are found with disease they are the cause of it, and that if injected germs will cause disease, inhaled or ingested germs will do the same, is surely a “foundation of sand.”

Dr. Fraser presented a summary of the facts:

1. That germs follow the onset of disease.

2. That many diseases have a chemical origin.

3. That germs may be inhaled or ingested without harm.

In the 1933 book The Golden Calf: An Exposure of Vaccine Therapy, author Charles W. Forward argued that no other hypothesis had ever been built on a flimsier foundation than the germ “theory” of disease. He claimed it had destroyed medicine as an art, failed to re-establish it as a science, and instead transformed it into a commercial enterprise that systematically exploited both sickness and the fear of sickness for profit:

“It is doubtful if any superstructure in the shape of hypothesis has ever been raised upon flimsier basis of fact than the theory of the specific "germ" as the causative factor in disease, the theory that each disease has its own particular bacterium, and that, in the words of Florence Nightingale, as quoted by Tyndall, the matter of each contagious disease reproduces itself as rigidly as if it were dog or cat.”

“This so-called "Germ" Theory has brought about a revolution in medical treatment. It has destroyed medicine as an art, and failed to re-establish it as a science. By means of it medicine has become commercialized, and sickness and the fear of sickness are systematically exploited for pecuniary profit.”

American physician Dr. William Howard Hay offered a similar critique in his 1940 essay Who Are The Quacks?, an eight-page exposé critically examining the medical industry while challenging the germ “theory” of Pasteur and Koch. He pointed out that not a single germ had ever fulfilled Koch’s Postulates—the widely accepted criteria required to establish a microbe as the cause of a specific disease—and argued that Pasteur’s promotion of germ “theory” had set medical science back by sixty years:

“This theory of germs as the cause of disease was analyzed by Prof. Robert Koch, who formulated a dictum, accepted by the scientists of his time, that must be met in order to fix on the germ as a cause of disease.

According to this dictum if the germ caused the disease it must be present in every case of this disease; it must not be present except in conjunction with the disease, it must be susceptible of separate cultivation in proper media outside the body, and finally, it must be susceptible of transplantation again in the human body, where it must infallibly produce the same disease.

The germ theory does not meet a single one of these conditions infallibly, the germ frequently being absent from diseased conditions which are attributed to it; being generally present in bodies in which the disease attributed to it is most conspicuous by its absence! And while germs are susceptible to cultivation outside the body, in suitable media, yet they are subject to mutation as the medium is changed in character, and, if again introduced into the body, they do not always infallibly cause the disease they are supposed to cause, generally not causing disease of any kind whatsoever.

Pasteur has already set us back sixty years by his advertising of the germ theory, and if we go back to the teachings of Bechamp, recognizing the microzyma as the prime cause, and the germ as a development of a biochemical nature, result of the condition of the body, transformed into a necessary scavenger to remove from the body objectionable matter, we will perhaps regain the ground lost for over sixty years, and be able to concentrate our attention on the soil conditions in the body, not on the harmless germ scavenger.”

In the book The Medical Mischief, You Say!: Degerminating the Germ Theory, a 1947 passage from The Homeopathic Review by Royal E. S. Hayes, M.D was reprinted. Hayes did not hold back, describing germ “theory” as “the greatest travesty on science,” “a ghastly medical farce,” and “the biggest hoax” the medical profession ever embraced:

“The germ theory of disease is the greatest travesty on science that was ever stumbled over during this semicivilized age; the most ghastly medical farce in which the human mass ever played its part; the biggest hoax the medical profession ever took in after with little hesitation and no mastication.”

Even within mainstream science, doubts persisted. By the 1950s, prominent immunologist René Dubos—himself a supporter of germ “theory”—warned against its overreach in his essay Second Thoughts on the Germ Theory (which I examined here). Dubos argued that the “theory” was oversimplified and rarely aligned with the actual facts of disease. He likened it to a cult—one that ignored inconsistencies and showed little concern for weak or contradictory evidence. He also noted how historians often glossed over the fact that many clinical observations by physicians and hygienists could not be fully explained by the germ “theory” of disease:

“The germ theory of disease has a quality of obviousness and lucidity which makes it equally satisfying to a schoolboy and to a trained physician. A virulent microbe reaches a susceptible host, multiplies in its tissues and thereby causes symptoms, lesions and at times death. What concept could be more reasonable and easier to grasp? In reality, however, this view of the relation between patient and microbe is so oversimplified that it rarely fits the facts of disease. Indeed, it corresponds almost to a cult-generated by a few miracles, undisturbed by inconsistencies and not too exacting about evidence.

Historians usually give a biased account of the heated controversy that preceded the triumph of the germ theory of disease in the 1870s. They barely mention the arguments of those physicians and hygienists who held that clinical observations could not be completely explained by equating microbe with causation of disease. The critics of Louis Pasteur and Robert Koch pointed out that healthy men or animals were often found to be harboring virulent bacteria, and that the persons who fell victim to microbial disease were most commonly those debilitated by physiological disturbances. Was it not possible, they argued, that the bacteria were only the secondary cause of disease-opportunistic invaders of tissues already weakened by crumbling defenses?”

Likewise, in 1968, Dr. Gordon T. Stewart, professor of Epidemiology and Pathology at the University of North Carolina—and himself a proponent of the germ “theory” of disease—wrote in his article Limitations of the Germ Theory that it was a gross oversimplification, unable to account for exceptions and anomalies. Over time, he warned, it had become an unquestioned and uncritically accepted dogma:

“The germ theory of disease—infectious disease is primarily caused by transmission of an organism from one host to another—is a gross oversimplification. It accords with the basic facts that infection without an organism is impossible and that transmissible organisms can cause disease; but it does not explain the exceptions and anomalies. The germ theory has become a dogma because it neglects the many other factors which have a part to play in deciding whether the host/germ/environment complex is to lead to infection. Among these are susceptibility, genetic constitution, behaviour, and socioeconomic determinants.”

These are but a few examples of voices that spanned a century, and there are many others that have been uncovered. They were not fringe thinkers, but trained scientists, physicians, and observers who questioned the legitimacy of a “theory” that quickly became dogma. They warned—correctly—that correlation was mistaken for causation, that authority replaced evidence, and that this error would reshape medicine for profit rather than for healing. Their words remain as relevant now as ever.

Dr. Montague R. Leverson

One important voice I’ve deliberately left out of the previous quotes is that of Dr. Montague R. Leverson—not because his contributions were minor, but because they merit closer attention. While many of the individuals quoted above offered sharp and insightful critiques of germ “theory,” Dr. Leverson played a unique and indispensable role in preserving the work of one of its most formidable scientific challengers: Antoine Béchamp.

It is largely thanks to Dr. Montague Leverson that Béchamp’s achievements—and the controversy surrounding Pasteur’s appropriation of them—are known at all today, particularly in the English-speaking world. Upon encountering Béchamp’s writings in New York, Leverson immediately recognized their significance and, as revealed in the preface of his subsequent translation of Bechamp's The Blood And Its Third Element, began a regular correspondence with the French chemist regarding his research and remarkable discoveries. He eventually traveled to Paris with the specific intention of meeting Professor Béchamp in person—just weeks before the latter’s death.

There, over the course of fourteen days of nearly daily conversations, Leverson heard directly from Béchamp about the plagiarism committed by Pasteur and the deeper scientific truths that had been buried by the rise of germ “theory.” Deeply moved by what he learned, Leverson became committed to restoring Béchamp’s rightful place in history and to sharing the suppressed insights he had received with the world.

His meticulous notes from these meetings were originally intended to serve as a special chapter in his own comprehensive work, Inoculations and Their Relations to Pathology, a book he had been researching and writing exclusively for over fourteen years. However, after Béchamp’s death, Dr. Leverson concluded that it would better serve the English-speaking public if Béchamp’s discoveries were published more directly, alongside translations of his original work.

Following Béchamp’s funeral in Paris in 1908, Leverson relocated to England, where he met Ethel Douglas Hume a few years later. He spoke at length with her about Béchamp’s scientific achievements and the fraud he believed had been committed by Pasteur. These conversations sparked Hume’s interest and led her to investigate the matter further.

Eventually, Mr. A. H. H. Lupton shared Dr. Leverson’s unfinished manuscript with Hume—a disorganized collection of quotations from Béchamp’s writings, presented without references or structure. Though the material was not publishable in its original form, Hume agreed to take on the task of editing it. The project ultimately evolved into her own widely read book, Bechamp or Pasteur: A Lost Chapter in the History of Biology—still the most thorough English-language work on the subject.

In this way, Dr. Leverson served as the critical link between Béchamp and Hume. Without his initiative and dedication, much of Béchamp’s work may have remained buried in obscurity, and the historical record even more distorted. His role was not only that of a messenger, but of a bridge between generations—preserving a suppressed legacy so it might be rediscovered in our time.

Just as Dr. Leverson preserved the legacy of Antoine Béchamp for a new generation of truth-seekers, I hope to do the same for Dr. Leverson. His own writings—particularly An Inquiry into the Logical Basis of the Germ Theory—deserve renewed attention. In presenting his work here, along with supplemental commentary, I aim to highlight the clarity and depth of his reasoning. Leverson didn’t merely reject the assumptions of germ “theory”—he dismantled them through methodical, logical critique that remains strikingly relevant in an age where belief still too often overshadows proof. Like Béchamp’s, his voice was nearly erased. But truth has a way of resurfacing—and now is the time to let it speak again.