It shows that anesthetics work better when they are able to dissolve in fat. The theory is that the anesthetic dissolves in the very thin layer of fat that surrounds the nerve cells, and stops them from functioning properly. This is what is thought to knock people out and make them stop feeling pain.
I should say, by the way, that I’m not an expert on any of this stuff. I just read loads about it on Wikipedia a few weeks back!!
p.s. found this great quote on Wikipedia:
“On 4 November 1847, the Scottish obstetrician James Young Simpson discovered the anaethestic qualities of chloroform when he and his friends were experimenting with different substances on themselves in search of a replacement for ether as a general anesthesia.”