174 HISTORY OF BRITISH ZOOPHYTES. 
they had all taken up their position there. He repeated 
this experiment so often, that he was thoroughly convinced 
that they preferred the lightest part. 
In continuing his observations, the idea again recurred 
that it was still possible that the body and the arms might 
be branch and roots of some little aquatic plant, and to 
satisfy himself he had recourse to the following experiment. 
He divided a polype into two, cutting it transversely, saying, 
that if both lived, and became perfect polypes, he would 
conclude that they were plants. A person might have 
thought that he would from this have concluded that they 
were animals; but being more disposed to regard them as 
animals, he expected that both pieces would die. He placed 
a polype in a shallow plate and cut it across, and the mo- 
ment he did so both pieces contracted so as to become like 
little green grains. The same day, however, they both 
expanded, and he could easily distinguish the one from the 
other, as the one which had the head and arms was a little 
longer than the other, which had neither head nor arms, 
and which he regarded as the tail. But extension was not 
the only sign of life given by the larger one; he saw it 
move its arms, and by the use of its arms he saw it change 
its place. On shaking the glass, both of them contracted, 
