ALG.^. 159 



cules greatly resembling those of plants, it has also 

 a definite organ unknown in the vegetable world, in 

 which the active molecules appear to enjoy an inde- 

 pendent motion, and the parietes of which appear 

 capable of contracting upon its contents. 



2. That the green gelatinous body is contained in 

 a membranous envelope, which, while it is elastic, 

 contracts also upon the action of certain reagents, 

 whose effects cannot be considered purely chemical. 



3. The comparison of the supposed ova with cyto- 

 blasts and cells of plants precludes the possibility of 

 our considering them as the latter, while the appear- 

 ance of a vitelline nucleus, transparent but molecular 

 fluid, a chorion or shell determines them as animal 

 ova. It was shown to be impossible that these eggs 

 had been deposited in the empty shell by other 

 infusoria, or that they were the produce of some 

 entozoon. 



4. That while it was impossible to determine 

 whether the vague motions of Closterium were volun- 

 tary or not, yet the idea the author had formed of a 

 suctorial apparatus forbade his classing it with plants. 



Lastly. In no instance had the action of iodine 

 produced its ordinary effects upon starch or vegetable 

 matter, by colouring it violet or blue, although Meyen 

 asserts it did in his trials. 



Hence the author concluded that Closterium must 

 still be retained as an infusory animal.^ 



Seven years later M. Eckhard contended still 

 for the animal nature of these Desmids. He said 

 that "the grounds for their being of animal nature 



' Annah of Natural History (August, 1840), vol, v. p. 415. 



