Structure and Division of the Vegetable Cell. 203 



body — a starch centre. Certain of the cup-shaped struc- 

 tures are continuous with, and apparent expansions of, the 

 fibres which suspend the nucleus in its place (Plate X. 



fig. 1). 



Occupying the centre of the cell is a large oval or 

 spherical nucleus, quite free, ordinarily, from the peripheral 

 protoplasm, but moored in its position in the way 

 already described. Inside is a large spherical nucleolus. 

 Let us now study the structure of the nucleus a little more 

 closely. The surface of it is seen to be bounded by a clear 

 hyaline zone exhibiting a double contour. With the out- 

 side of this the radiating threads seem to be fused ; but the 

 strong probability is — judging from homologies with animal 

 cells, and their behaviour, as subsequently brought out — 

 that these ^ass through, and are continuous with, those inside 

 the nucleus. 



A most remarkable and instructive result w^as obtained 

 on trying the efi'ect of endosmosis and simultaneous stain- 

 ing on the cells. A fresh filament was adjusted under the 

 field of the microscope near the edge of the cover glass, so 

 that the nucleus of a particular cell was well defined. A 

 few drops of alcoholic solution of eosin were then allowed to 

 fall on the slide at the edge of the glass, care being taken 

 that in the currents set up the definition of the nucleus 

 remained clear. Endosmosis was very speedily efi'ected, 

 the elongated cylindrical cells swelling out notably, while 

 by the action of the stain the nucleus and nucleolus became 

 more distinctly visible ; owing to the swelling out of the 

 protoplasmic lining, and the carrying with it of the chloro- 

 phyll bands, a strong tension was set up in the connecting 

 threads. This became so great that these suddenly ruptured 

 simultaneously or in rapid succession, one or two remaining 

 attached on one side only to the bands, and towards this 

 side the nucleus, after tumbling about in a confused manner, 

 settled down. The broken and curled-up ends of the 

 threads could, for a moment or two, be noticed surround- 

 ing the hyaline zone, but soon the latter detached itself 

 with a sudden jerk and swelled out, forming a translucent 

 sphere attached on one side to the nuclear substance, which 

 now took on rather a shrivelled outline (Plate X. fig. 2.) 

 To the swollen and spherical zone, which goes on increas- 



