Koch’s Postulates Explained

The Following is an excerpt from Life Science Course LESSON 66 – Contagion, Epidemics

8. KOCH’S POSTULATES

The German scientist, Robert Koch, maintained that for a specific bacteria to be the cause of a disease:

1. It must be found in every case of that disease.
2. It must not be found when the disease is not present.
3. It must be capable of living outside the tissues.
4. It must then be capable of reintroduction into the organism and producing that disease.

As has been repeatedly demonstrated, specific bacteria do not fulfill these prerequisites.

Robert Koch (1843-1910) was a bacteriologist, physiologist, and one of Pasteur’s contemporaries. The specific requirements of “Koch’s Postulates” follow:

1. A culture of the bacteria must be taken from a diseased animal.
2. It must then be grown in pure culture in a laboratory.
3. After this, the culture has to be injected into a susceptible animal.
4. It must cause the same disease, and culture must be taken from this animal.

This is a modification of the germ theory, requiring a condition of susceptibility to establish a causal relationship between specific germs and specific diseases.

Scientists know that specific bacteria are not found in every case of a specific disease. The eminent Canadian physician, Sir William Osier (1849-1919) found that the diphtheria bacillus is absent in 28 to 40% of cases of diphtheria. Green’s Medical Diagnosis says that tubercle bacilli may be present early, more often late, or in rare instances be absent throughout the disease condition. Koch’s first postulate, “the specific bacteria must be found in every case of that disease” is not fulfilled in tuberculosis, diphtheria, typhoid fever, pneumonia, or any other disease. Specific bacteria are not found in every case of a specific disease.

Nor is the second postulate fulfilled, because it is a medically-known fact that bacteria are found in the bodies of humans and animals which exhibit no symptoms of any disease. Specific bacteria are repeatedly found when the specific disease is absent.

Further, bacteria are not capable of living outside the tissues; therefore, the third postulate is not fulfilled. Neither Pasteur nor any of his successors have ever induced a complaint by the inoculation of airborne bacteria, but only by injections from bodily sources. The reason is obvious: germs are dependent on human or animal organisms for their survival.

Quoting from “The Germ Theory Reexamined” by Bob Zuraw and Bob Lewanski (Vegetarian World, Volume 3, Number 11, September-November 1977): “Koch’s Fourth Postulate: Introducing germ cultures in a healthy body or organism does not produce signs and symptoms of the disease.The Bio-Chemical Society of Toronto conducted a number of very interesting experiments in which pure cultures of typhoid, diphtheria, pneumonia, tuberculosis, and meningitis germs were consumed by the millions in food and drink by a group of volunteers. The results: no ill effects whatsoever.”

But when the condition of susceptibility is introduced, this changes the whole concept. Thus we are back to the same point we have been emphasizing: the condition of the host is of primary importance in the production of disease.