The germ – or microbian - theory of disease was popularized by Louis Pasteur (1822-1895), the inventor of pasteurization. This theory says that there are fixed, external germs (or microbes) which invade the body and cause a variety of separate, definable diseases. The health of one's biological terrain escaped consideration in this overly simplistic germ-centered disease model which holds that, in order to get well, you need to identify and then kill whatever germ made you sick. The tools generally employed are drugs, surgery, radiation and chemotherapy. Prevention includes the use of vaccines as well as drugs, which - theoretically at least - work by keeping germs at bay.
Just prior to the time that Pasteur began promoting the “monomorphic” germ theory, a contemporary by the name of Claude Bernard (1813-1878) was developing the theory that the body's ability to heal was dependent on its general condition or internal environment. Thus disease occurred only when the terrain or internal environment of the body became favorable to disease.
An extremely brilliant contemporary of Claude Bernard's was Antoine Bechamp (1816-1908). Bechamp had degrees in physics, chemistry and biology. In addition he was a medical doctor and a university professor. Bechamp built upon and extended Bernard's idea, developing his own theory of health and disease which revolved around the concept of “pleomorphism.”
Through meticulous research and in contrast to Pasteur's subsequent, misinformed promotion of "monomorphic" or single-formed, fixed state microbes (or germs), Bechamp had discovered tiny organisms (or microorganisms) he called “microzyma” which were “pleomorphic” or “many-formed.” (Pleo = many and morph = form.) Interestingly, these microzyma were found to be present in all things whether living or dead, and they persist even when the host has died. Many were impervious to heat as well.
Bechamp’s microzyma, including specific bacteria, could take on a number of forms during the host’s life cycle and these forms depended (as Bernard contended) primarily on the chemistry of their environment, or the biological terrain, or to put it a third way, the condition of the host. In other words there is no single cause of disease. Instead disease results when microzyma change form, function and toxicity according to the terrain of the host. Bad bacteria, viruses and fungi are merely the forms assumed by the microzymas when there is a condition or terrain that favors disease and these "bad" microzyma themselves give off toxic byproducts, further contributing to a weakened terrain. In fact, everything we've been told about viruses (and the germ theory) is wrong.
This is how Bechamp himself put it in his last book The Blood and Its Third Element. : ". . . the microzyma, whatever its origin, is a ferment; it is organized, it is living, capable of multiplying, of becoming diseased and of communicating disease. . . All mycrozyma are ferments of the same order - that is to say, they are organisms, able to produce alcohol, acetic acid, lactic acid and butyric acid. . . In a state of health the microzymas of the organism act harmoniously, and our life is, in every meaning of the word, a regular fermentation. In a state of disease, the microzymas do not act harmoniously, and the fermentation is disturbed; the mycrozymas have either changed their function or are placed in an abnormal situation by some modification of the medium. . ."
Through his research, Bechamp showed that the essence of life is a “fermentation” process of digestion, assimilation, disassimilation and excretion. Interruptions in any of these functions would result in a lack of energy, full blown disease or even death. Rather than causing disease, Bechamp showed that harmful mycrozyma – which Pasteur took to be external germs attacking a host - actually arises when the body's normal metabolic processes - or "fermentations" - are disturbed.
Thus, according to Bernard, Bechamp and their successors, disease occurs to a large extent as a function of biology and as a result of the changes that take place when metabolic processes are thrown off. Germs become symptoms that stimulate the occurrence of more symptoms - which ultimately culminate in disease. A body thus weakend also naturally becomes vulnerable to external harmful microzyma - or if you prefer pleomorphic germs. So, our bodies are in effect mini-ecosystems, or biological terrains in which nutritional status, level of toxicity, level and types of stress, and digestive function all play key roles.
For these and other reasons Bechamp argued strenuously against vaccines, asserting that "The most serious disorders may be provoked by the injection of living organisms into the blood." Untold numbers of researchers have since agreed with him. An excellent discussion of Bechamp and Pastuer is here.