and its Nucleus in Chara verticillata. 19 



and first bunch of roots now described*. When a second plant- 

 stem is formed, which is not unfrequently the case, this is deve- 

 loped out of one of the root-buds ; hence it is not uncommon to 

 see one of the latter in an intermediate state. 



Now if we take the simple root-cell (fig. 2) about the eighteenth 

 hour after germination, when it will be about half an inch long 

 and ^~ of an inch broad, and place it in water between two 

 slips of glass for microscopic observation, under a magnifying 

 power of about 400 diameters, we shall find, if the circulation 

 be active and the cell-wall strong and healthy, that the extre- 

 mity of the latter, together with the nucleus and fixed protoplasm, 

 which, as before stated, is about a hundreth part of an inch long 

 and g^^y broad, will, in the course of about twenty-four hours, 

 present the following changes : — 



\st stage. — The nucleus, now about -q~ of an inch in dia- 

 meter, is situated in that part of the fixed protoplasm which is 

 next the rotating one; it is also now^ globular, and its nucleolus, 

 which is about the i-^qq of an inch in diameter, spherical and 

 opake, with the exception of the single hyaline vacuole in the 

 centre. After this, the nucleolus becomes somewhat flattened, 

 its outline becomes subcircular, and it presents several hyaline 

 vacuoles of different sizes. The " granules " are now also in 

 active motion at the other end of the fixed protoplasm, close to 

 the extremity of the cell-wall, but, beyond these and the " irre- 

 gularly shaped bodies," the fixed protoplasm presents nothing to 

 interrupt its uniformity throughout its whole extent. 



2nd stage. — After a certain time, during which the nucleolus 

 has been successively changing its shape from a subrotund to an 

 elongated form, and vice versa, it assumes a grumous appearance, 

 becomes slightly enlarged, and growing fainter in its outline, gra- 

 dually but entirely disappears, leaving a white space correspond- 

 ing to its capsule or cell-wall, with a faint remnant of some 

 structure in the centre. Subsequently this space becomes filled 

 up with the fixed protoplasm, and after about an hour and a half, 

 (but this varies,) the nucleus reappears a little behind its former 

 situation, but now reduced in size, and with its nucleolus double, 

 instead of single as before (fig. 9) ; each nucleolus being about 

 one-fourth part as large as the old nucleolus, and hardly percep- 

 tible. Meanwhile a faint septum (fig. 3 g) is seen obliquely ex- 

 tending across the fixed protoplasm, a little beyond the nucleus ; 

 and, if iodine be applied at this time, the division is seen to be con- 

 fined to the protoplasm, as the latter, from contraction, withdraws 

 itself from each side of the line where the septum appeared, and 



* Ann. and Mag. Nat. Hist. loc. cit. p. lOG, &c., pi. 8. fig. 35. 



2* 



