Development f and Structure of the Vegetable Cell. ?8'?^ 



I have represented in Plate VII. the structures observed 

 by myself, and which correspond in character with these globules 

 of Bary. The phenomenon occurred in (Edogonium grande ; 

 the entire contents coalesced into a ball-like mass, which was 

 protruded through a circular aperture in the thick-walled joint- 

 cell, and formed on the outside a spore-like globule (PI. VII, 

 fig. 50). Alongside the opening there was a small disk, the size 

 of the aperture, mostly adherent to one side of it, and which, 

 without doubt, had originally closed it before being thrust out 

 by the emerging cell-contents (fig. 50«?). The extruded, glo^ 

 bular, spore-like corpuscle consisted of several nested cells, the 

 two outer membranes of which frequently contained a single 

 layer of small starch-vesicles, whilst the third was filled with 

 chlorophyll and starch, and the fourth was occupied by reddish- 

 brown vesicles. 



The globular corpuscle was enveloped within a delicate transpa- 

 rent cell as in a sac, which was fixed by its lower and somewhat 

 elongated extremity to the inner wall of the joint-cell near the 

 circular aperture. Solution of iodine and chloride of zinc gave 

 a beautiful violet-blue tint both to the saccular envelope and to 

 the membrane of the globule. Bary did not remark this cellu- 

 lose reaction of the enveloping sac ; and in fact it is difficult to 

 produce the coloration in the older globules which have been 

 longer extruded from the mother cell. Yet, even under these 

 circumstances, the true membranes of the globule are readily 

 coloured blue. At a later phase of their development the starch- 

 corpuscles vanish, and their walls become thickened and reticu- 

 late, or slightly porous (fig. 52). 



The globule enclosed within the sac exhibits a mucilaginous 

 peduncular body at its base, which is adherent, together with the 

 lower end of the envelope, to the inside of the joint-cell. It 

 appeared to me to be an inner envelope, which, however, is not so 

 extended at this lower extremity as the outer one. The stem- 

 like prolongation is also coloured blue by the same reagents. 



Bary considers the saccular envelope to be a young membrane 

 formed, probably at the time of extrusion, around the primordial 

 sac, and continuous with the innermost layer of the emptied 

 joint-cell. Consequently the outer membrane of the globule, or 

 the delicate covering which in all probability serves as a lining to 

 the sac and is prolonged into its pedicle, would be the secondary 

 cell of the joint-cell. 



For my own part, I have not witnessed the first act of coales- 

 cence of the cell-contents, but only the formation of such 

 globules after they have begun to extrude from the circular 

 aperture, and therefore have no knowledge of the origin of the 

 different component membranes. 



