Bacteria are very in these days—in probiotic drinks, in news articles, and in scientific research about the connections between healthy microbes and healthy bodies. A growing chorus of post-pasteurian voices are advocating for a new relationship with microbes, one where bacteria are respected and diverse ecosystems valued over sterile surfaces.

In 1892, the biologist Herbert Conn was making startlingly similar arguments for the value of microbes as much more than just germs. He gave his post-pasteurian lecture, "Some Uses of Bacteria" (PDF), only about thirty years after Louis Pasteur invented his method for killing bacteria. Speaking to an audience of farmers, he starts by explaining the value of having a good stock of bacteria around the farm:

The farmer has learned to-day that he must keep a good breed of cows and a good breed of stock in general, but farmers generally do not appreciate that it is equally necessary to keep a good breed of bacteria. You cannot make butter or cheese without cows; you cannot make butter or cheese satisfactorily without bacteria. You cannot cultivate your fields without your horses to help you, but all the cultivation that you might give your fields would be useless were it not that these little creatures of which I shall speak this morning come in after you get through and complete the process which you have begun.

Most striking though is his telling of the history of microbiology and how it had influenced popular understanding of bacteria, surprising for its similarity to what a lot of people have been saying much more recently (myself included!):

Bacteria are in rather bad odor in the minds of most people, and we are all inclined to look with horror upon them. We have a sort of shrinking when any one speaks to us of the number of bacteria in the milk which we drink. The reason for this, however, is simply an historical one. When bacteria were first discovered it was early noticed that they had a causal relation to disease, and scientists went to work from the very first to investigate diseases in relation to bacteria. The result was that after a few years a great deal of information had accumulated, showing that bacteria caused diseases. The so-called " epidemics " are usually the result of bacteria, and with minds intent upon this side of the question scientists did not pay much attention to the good that bacteria might do in the world. It was more interesting to study disease. People are very much interested when you begin to tell them why it is that they have small-pox, why it is that they have yellow fever; the other side of the matter, however, is not so interesting.

But the fact is that the bacteria story has only been half told, and thus far it is the smaller half that has been told, if there is such a thing as the smaller half. It is true that bacteria are occasionally injurious to us, but it is equally true that they are of direct benefit to us.

Today, more than a hundred years after Conn's lecture, the bacteria story is still being told, through microbiome studies and artisanal cheesemaking. As microbes become mainstream, their story is increasingly becoming our own.

(Thanks to Richard for sharing the article with me!)