Closterina.] THE INFUSORIA. 145 



with the water in which the Closterium resides, any motion 

 was communicated to the particles of such colouring mat- 

 ter by the supposed papillae, or by the active molecules 

 within the terminal cells. A circulation of the fluids 

 within the shell was observedj independent of the vague 

 movements of the active molecules ; this was regular, 

 passing in two opposite currents, one along the side of 

 the shell, and the other along the periphery of the 

 gelatinous body. When the shell and body of the Clos- 

 terium was broken by pressure, the green gelatinous matter 

 was forcibly ejected by the contraction of the membranous 

 envelope. 



The action of iodine upon the specimens was very 

 remarkable: 1st, it did not, as reported by Meyen, stain 

 the green body violet or purple, but orange-brown : 2nd, 

 it produced violent contraction of the investing mem- 

 brane of the body, whereby the green matter was often 

 forcibly expelled from the shell at the transverse division ; 

 it instantly annihilated the motion of the molecules in 

 the terminal sacs, and the sacs themselves became so 

 distended with fluid as to burst, and allow the molecules 

 to escape. — The following are Mr. D.'s reasons for classing 

 it with animals : — 



" 1st. That while Closterium has a circulation of mole- 

 cules greatly resembling that of plants, it has also a 

 definite organ, unknown in the vegetable world, in which 

 the active molecules appear to enjoy an independent 

 motion, and the parietes of which appear capable of con- 

 tracting upon its contents. 



*' 2ndly. That the green gelatinous body is contained in 

 a membranous envelope, which, while it is elastic, con- 



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