IN 1786, a student of Luigi Galvani鈥檚 at the University of Bologna, Italy, was startled to find that a dead frog鈥檚 leg kicked when he touched a scalpel to its sciatic nerve. Galvani worked out that the metallic implement had been charged with static electricity, which he took to be the agent that activated muscles in living animals.
This idea 鈥� which Galvani termed 鈥渁nimal electricity鈥� 鈥� went on to become highly influential. Most famously, Mary Shelley wondered if electricity could be used to reanimate the dead (though the lightning-bolt scene familiar from the Frankenstein movie didn鈥檛 actually feature in Shelley鈥檚 novel).
We鈥檝e long known that cells use ions dissolved in water to carry out a huge range of functions, from animating our brains to powering our bodies. Now we have found bacteria in the ground that eat electrons from minerals directly, and pass them back out, without the need for the sugars or oxygen that most life forms use to mediate the process (see 鈥�Meet the electric life forms that live on pure energy鈥�).
Advertisement
These bacteria seem to come in many varieties. There might even be some among the teeming bacterial hordes in your gut. And their discovery means we are on the verge of finding out just how little electricity fundamental life requires.
Two hundred and twenty-eight years later, we are still feeling the kick of that frog鈥檚 leg.
This article appeared in print under the headline 鈥淪park of life revisited鈥�
