"But not until the recent advent of genomic sequencing that can read the DNA of our cells did biologists appreciate just how many of them [microbial cells] there were within us: for every one human cell in our body, there are ten microbial cells.
"The idea that we're more microbe than mammal is as or more profound than the theory of evolution," says anthropologist Jeff Leach, one of the founders of the American Gut Project, which is devoted to genetically mapping the microbiome."
When I first read this, I was immediately struck by what seemed to me to be it's essential wrongness -- that is to say, it seemed to me fairly obvious that the bulk of a human body, no matter how many microbial cells versus human cells there are, is made up of human cells. In other words, if one were to weigh or calculate relative volume, human cells would surpass microbial cells.
My gut (no pun intended) told me that it was likely that individual microbial cells were smaller than individual human cells, and a little searching on the Internet turned up the proof of my intuition:
"All the bacteria living inside you would fill a half-gallon jug; there are 10 times more bacterial cells in your body than human cells, according to Carolyn Bohach, a microbiologist at the University of Idaho (U.I.), along with other estimates from scientific studies. (Despite their vast numbers, bacteria don't take up that much space because bacteria are far smaller than human cells.) "
To assert that "we're more microbe than mammal" because there are more individual microbial cells than human cells in our bodies is akin to saying that because an average human being has more hairs (somewhere around 100,000) than muscles (somewhat less than 1000), an average human being is more hair than muscle. Obviously, this is ridiculous… and just one more example of the distressing tendency towards ludicrous exaggeration in our society.
To me, it points to a real lack of confidence in what one is trying to say -- that one needs to exaggerate so profoundly to make what one is saying seem worthy enough. -- PL