Hydra's Heads and Medusa's Blood
33
first to elucidate the social life and sexually divided caste system of bees.
Due to his eclipse in later years by court-supported scientists who valued
"common sense" over observation, Reaumur's exhaustive study of ants
wasn't published until 1926. In the interim it had taken several genera-
tions of formicologists to cover the same ground, including the descrip-
tion of winged ants copulating in flight and proof that they aren't a
separate species but the sexual form of wingless ants. In 1734 he pub-
lished the first of six volumes of his Natural History of Insects, a milestone
in biology.
Reaumur made so many contributions to science that his study of
regeneration was overlooked for decades. At that time no one really
cared what strange things these unimportant animals did. However, all
of the master's work was well known to a younger naturalist, Abraham
Trembley of Geneva, who supported himself, as did many educated men
of that time, by serving as a private tutor for sons of wealthy families. In
1740, while so employed at an estate near The Hague, in Holland,
Trembley was examining with a hand lens the small animals living in
freshwater ditches and ponds. Many had been described by Reaumur,
but Trembley chanced upon an odd new one. It was no more than a
quarter of an inch long and faintly resembled a squid, having a cylin-
drical body topped with a crown of tentacles. However, it was a star-
tling green color. To Trembley, green meant vegetation, but if this was
a plant, it was a mighty peculiar one. When Trembley agitated the
water in its dish, the tentacles contracted and the body shrank down to a
nubbin, only to reexpand after a period of quiet. Strangest of all, he saw
that the creature "walked" by somersaulting end over end.
Since they had the power of locomotion, Trembley would have as-
sumed that these creatures were animals and moved on to other observa-
tions, if he hadn't chanced to find a species colored green by symbiotic
algae. To settle the animal-plant question, he decided to cut some in
half. If they regrew, they must be plants with the unusual ability to
walk, while if they couldn't regenerate, they must be green animals.
Trembley soon entered into a world that exceeded his wildest dreams.
He divided the polyps, as he first called them, in the middle of their
stalks. He then had two short pieces of stalk, one with attached tenta-
cles, each of which contracted down to a tiny dot. Patiently watching,
Trembley saw the two pieces later expand. The tentacle portion began to
move normally, as though it were a complete organism. The other por-
tion lay inert and apparently dead. Something must have made Trem-
bley continue the experiment, for he watched this motionless object for
nine days, during which nothing happened. He then noted that the cut