WILTIMS #23: On the shoulders of giants

Yesterday, one of our professors told an interesting anecdote during his lecture on the liver. His story started in ancient Greece - in the time of Hippocrates, the father of medicine. At the time it was believed that all body fluids were some combination of the four humors: sanguine (blood), choleric (plasma), melancholic* (clotted blood) and phlegmatic (mysterious off-white substance). Now before you dismiss this as crazy pseudo-science from 500 BC, you must understand the basis for the idea.

Note the illustration of stratified
blood serum at the top right

Physicians of the Hippocratic school would take a blood sample from their likely aristocratic patient and allow it to sit and settle. When it had, they noticed four layers (the four humors). Makes sense so far... However, when they looked at a healthy person's blood, they only saw 3 layers. The enigmatic phlegmatic humor was only present in people with fevers, certain illnesses and in pregnant women.

This is actually amazingly good science. The bloodletting they prescribed for this was less than brilliant, but given that we wouldn't discover the identity of the phlegmatic humor for over 2000 years, I'm willing to let it go.

It turns out the whitish substance is actually fibrinogen clotting factors produced by the body's inflammatory response. Even today, we test for this quality in blood. It's called an estimated sedimentation rate (ESR) test and it was actually the principle indicator of my recovery from lymphoma (and it's the nerve wracking number I wait for at every checkup).

How does all this relate to the liver? The fibrinogen protein is actually made in the liver after stimulation by interleukin-6. Why did my professor tell us this lengthy story? In the 1980s, he was the co-discoverer of IL-6.

TIL: Very little, especially of interest. Let's go with: Amacrine cells are the only nerves that have no axon and they are only found in the retina.