Hydra's Heads and Medusa's Blood
39
THE SALAMANDER'S NERVOUS SYSTEM—FORERUNNER OF OURS
This early regeneration research, Spallanzani's in particular, was a
benchmark in modern biology. Gentlemanly observations buttressed by
"common sense" gave way to a more rigorous kind of examination in
which nothing was taken for granted. It had been "known" for perhaps
ten thousand years that plants could regenerate and animals couldn't. To
many zoologists, even twenty years after Trembley's initial discovery,
the few known exceptions only proved the rule, for octopi, crayfish,
hydras, worms, and snails seemed so unlike humans or the familiar
mammals that they hardly counted. The lizard, the only other vertebrate
regenerator then known, could manage no more than an imperfect tail.
But the salamander—here was an animal we could relate to! This was no
worm or snail or microscopic dot, but a four-limbed, two-eyed verte-
brate that could walk and swim. While its legendary ability to with-
stand fire had been disproven, its body was big enough and its anatomy
similar enough CO ours to be taken seriously. Scientists could no longer
assume that the underlying process had nothing to do with us. In fact,
the questions with which Spallanzani ended his first report on the sala-
mander
have
haunted
biologists ever since:
"Is it to be hoped that
[higher animals] may acquire [the same power] by some useful disposi-
tions? and should the flattering expectation of obtaining this advantage
for ourselves be considered entirely as chimerical?"