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 wouhl 

 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 exi)ected 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, 



