DEVELOPMENT OF CHARA. 221 



" While the component parts of the first cell of the root 

 of Chara are still fresh in the mind of the reader, it seems 

 advisable that they should be compared with those of 

 Amoeba. Chara lives by nutriment obtained through 

 endosmosis ; Amoeba, by taking in the crude material 

 direct, and, having abstracted the nutritious parts by the 

 process of digestion, ultimately throwing off the refuse. 

 Chara is a vegetable, though there are animal cells, which 

 also live by endosmose ; but Amoeba cannot be a vegetable, 

 if we admit the distinction that I have given, viz. the 

 taking in of crude form material. Nevertheless, the 

 root-cell of Chara and Amoeba greatly resemble each 

 other. 



" Thus the cell- wall of the former corresponds with the 

 pellicular secretion or capsule of Amoeba, which, in Arcella, 

 &c. appears as a shell. The protoplasmic sac may corre- 

 spond with the pellicula itself and diaphane. The nucleus 

 is identical, and situated in the fixed portion of the proto- 

 plasm, as it appears in the fixed molecular sarcode of 

 Amoeba, when the latter assumes a spherical form. The 

 most interesting point, however, which this analogy brings 

 forth, is the correspondence between the rotatory motion 

 of the protoplasm in the cell of Chara, and that of the 

 sarcode of Amoeba and other infusoria ; since, by consider- 

 ing this motion in different organisms, we may, perhaps, 

 arrive at some notion of the cause by which it is produced 

 in all. In the Planarice and fiotatorice, the lash of cilia, 

 which projects from the hepatic cells that line the stomachs 

 of these animalcules respectively, appears to rotate the 

 food during the process of digestion ; but in the second 

 part of the alimentary canal of the Eotatoria, where there 

 are no hepatic cells, the surface is seen, on the approach 

 of anything into it, to be covered with cilia. Again, in 

 Vorticella and Paramecium Aurelia, the digestive globules 

 also are slowly circulated round the abdominal cavity, if I 

 may so term it, in the midst of the sarcode, or internal 

 mucus ; and when we watch this circulation narrowly, for 

 instance, in the posterior part of Vaginicola crystallina 

 (Ehr.), we see that the bodies in which the chief motion 

 exists are very minute, and apparently stationary, and 

 that, while their movements are very rapid, the circulation 



