FUNCTION.] ROTATION WITHIN CELLS. 331 



by means of galvanic agency ; but that the phenomenon is 

 correctly described by the ingenious author, and that it is 

 constantly operating in plants, are beyond all dispute. It is 

 by endosmose that vapour is absorbed from the atmosphere, 

 and water from the earth ; that sap is attracted into fruits by 

 virtue of their greater density ; and, probably, that buds are 

 enabled to empty the tissue that surrounds them, when they 

 begin to grow. 



But, although endosmose will be found a ready explanation 

 of many of the phenomena connected with the ordinary move- 

 ment of fluids, it throws no light upon rotation, which, so 

 far as we at present know, is a motion inexplicable upon any 

 principle yet discovered, and it by no means dispenses with 

 the vital force which, after all, offers the best explanation of 

 most of the phenomena of life. 







Of Rotation. 



This kind of motion is confined to plants of a low organi- 

 sation, but not entirely to flowerless or cellular families. It, 

 however, forms for Professor Schultz an important physio- 

 logical means of separating the vegetable kingdom into two 

 primary classes, namely, Homorgana and Heterorgana : the 

 former of which, consisting wholly or in great measure of 

 cellular tissue, contains all the cellular flowerless, and some 

 flowering plants of a low organisation; the latter all the 

 higher flowering plants, and the vascular flowerless. It 

 consists in a special circulation of the fluid contained in the 

 interior of each cell, and is always so limited ; the rotation in 

 one cell never interposing or mixing with that in another 

 cell. The rotating sap of such plants is said by Schultz to 

 have the power of absorbing coloured fluids, while the cinen- 

 chymatous vessels, in which what he calls cyclosis goes on, 

 either do not take up any coloured fluid, or, at least, not till 

 they receive it in an altered state from other forms of tissue. 



Corti, in 1774, Fontana, L. C. Treviranus, and especially 

 Amici, made the earliest observations upon rotation. It was 

 found that if a portion of Nitella flexilis, or even of the crus- 

 taceous Charas, their opaque cuticle being first scraped away, 



