28 



regularly as in the valisneria, few if any passages exist, 

 and no difference is found in the motions in the cortical 

 and internal cells. The cells consist, each, of a bright trans- 

 parent membrane, or wall, of great tenuity — the mucus they 

 contain is translucent, of considerable tenacity, which is well 

 shown when the leaf has been pulled to pieces by needles, 

 and the mucus or albumen coagulated by alcohol and acids. 

 The nucleus is a granular mass, of different density to the 

 mucus, usually of a round or oval shape, and about aU inch 

 in diameter ; it is not adherent to any part of the cell wall, 

 but evidently possesses adhesive qualities, as it may be fre- 

 cpiently found to have attached to itself the whole of the 

 chlorophyll in the cell. 



" The globules of chlorophyll are of tliree kinds. One con- 

 sists of small round green granules about sro inch in diameter, 

 which are soft, easily flattened, soluble in boding water, but 

 are not turned blue by iodine. Another set consists of much 

 larger granules, which are scarcely tinged with green, and are 

 turned a very decided blue colour by iodine, showing their 

 identity with, or affinity to starch ; the third set consists of 

 globules shaped like a rounded wedge, having a coat and 

 tail of chlorophyll on a nucleus of starch. All these varie- 

 ties seem to be under the same influence, the circulation 

 taking place equally well in a cell that contains starch only 

 as in one that contains all three. 



" Eound the inner surface of the cell in the valisneria, the 

 author has repeatedly witnessed an indistinct Hue, in which 

 the globules evidently pass, and which seems to consist of 

 a thinner substance than the central mucus. This does not 

 exist when the whole contents are rotating. 



" The circulation consists in a slow and somewhat irregular 

 march of the nucleus, and some twenty or thirty green globules 

 round the cell that contains them — the central mucus and the 

 rest of the globules being at the same time in perfect quiescence. 



"The rapidity of the march varies from half an inch to 



