172 HISTORY OF BRITISH ZOOPHYTES. 
hittle animalcules swimming in it, though the longer he 
observed them the more he was disposed to question the 
correctness of this conjecture. 
One day he shook the jar in which they were enclosed, to 
see what effect it would have on them. ‘The result was very 
different from what he expected. Instead of seeing the 
body and arms agitated in consequence of being disturbed 
by the motion of the water, the whole suddenly collapsed 
into a little knob of green matter, and the arms quite dis- 
appeared. He was greatly surprised; but his curiosity bemg 
increased, he continued to watch them, and while he was 
observing them with a lens he saw them gradually expand, 
so as to resume their former appearance. He began then 
to be convinced that they were animals. The wonder was 
that he had not sooner been assured of this, for nearly forty 
years before they had been described as animals by Leeuw- 
enhoek, and by an anonymous Hnglish naturalist, but as 
their observations had not excited much attention, they had 
escaped his notice. Nay, even now he was not thoroughly 
convinced; for though they might resemble slugs that could 
contract their body and their horns, why might they not 
be a kind of sensitive plants, collapsing when they were 
touched ? 
