The Horses and the Eels

Alexander von Humboldt had, by his thirties, a reasonable claim to being the smartest man in Europe. He would invent ecology, hold the world altitude record for thirty years, and predict human-caused climate change from a lake in Venezuela. Goethe said talking to him was like holding a cup under a fountain with many pipes.

He also had a habit of testing hypotheses on himself.

In Berlin in the 1790s he raised chemical blisters on his own back, pressed metal electrodes into the raw flesh, and when the pain dulled he reopened the scabs with a scalpel. Then he sailed for South America.

At Calabozo in March 1800 he wanted to study Electrophorus electricus, the electric eel, and there was no clean way to catch one. So he drove thirty wild horses and mules into the pool. Two drowned. When the eels were exhausted he waded in barefoot and stood on one, dissected it while it kept shocking him, and wrote up the pain in the tone of a man taking dictation from himself: "violent pain in the knees, and in almost every joint."

It was, he wrote, worse than any Leyden jar he had ever touched.

This was, at that point in his life, a lot of Leyden jars.