Early stirrings of the germ theory

The germ theory of disease, which holds that certain diseases are caused by living organisms, occurred to people thousands of years ago, but  it was proved only in the 19th century.

In the western tradition, the Roman scholar Marcus Terentius Varro first laid out the germ theory in his book, On Agriculture, a practical guide published in about 36 B.C. In it, Varro advises the farmer against building near swamps because “certain minute animals, invisible to the eye, breed there and, borne by the air, reach inside the body by way of the mouth and nose and cause diseases that are difficult to get rid of.”

Varro was a prodigious scholar and well known public figure, and his works were highly influential. However, at least some of his contemporaries, apparently including the writer/philosopher/statesman Marcus Tullius Cicero, considered his germ theory a crackpot idea.

It is worth noting that the Atharva Veda, the first Indian book that addresses medical topics, includes a fairly detailed germ theory. The book identifies a number of living organisms that were deemed responsible for causing various diseases, and prescribes cures to kill the organisms. The Atharva Veda was written down about 200 B.C., but its ideas may date as far back as 1,000 B.C.

Disease viewed as a loss of balance

The "humoral theory" of disease, which originated with Hippocrates (who lived from about 460 to about 370 B.C.) and lasted until the early 20th century, held that a balance had to be maintained among four humors or liquid substances in the human body. If that balance got out of whack, the thinking was, people got sick.

The four humors were black bile, red or yellow bile, blood and phlegm. The ancients believed that these substances ruled our personalities as well as our bodies. They divided all the possible character types into these four — melancholic, choleric, sanguine and phlegmatic — depending on which substance dominated that particular person.

Treatments for disease were designed to restore the balance among the humors, but what worked for one person might not work for another, which helped let practitioners off the hook if a "cure" didn't work. Purges like enemas and emetics were popular, and physicians often advised changes to a patient's diet or routine. Blood-letting was an especially durable cure for just about anything.

During labor, for example, "some women were bled to unconsciousness to counter delivery pains" or any other complications large or small, according to Peter Conrad's The Sociology of Health and Illness.

The acceptance of the germ theory finally put an end to humoral theory in mainstream medical thought.

All aboard!

Remember, dear reader, I said there would be tangents. Now we are embarking on a trip to Baltimore, Md., and childbirth will barely be mentioned for a while.

Locomotion

In his groundbreaking 1982 book, The Social Transformation of American Medicine, Paul Starr plumbs the source of mainstream medicine's authority. Simply put, it comes from the public's dependence on the doctor's superior competence, real or perceived.

As the title of Starr's book suggests, doctors were not always able to lay claim to that authority. Indeed, before the germ theory was proved and methods of administering anesthesia devised, making possible the development of effective surgery, physicians had very little to offer. (That didn't keep them from practicing, though.)

But in Baltimore, late in the 19th century, with new technologies and understandings developing rapidly on all sides, events were unfolding that would help solidify the medical profession's authority.

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