128 Prof. H. Karsten on the Formation, 
the inner wall of the membrane of the secondary cell, which is’ 
then likewise engaged in development. But afterwards, when a 
more active assimilative energy is acquired by the previously 
resting nuclear cell for the purpose of its progressive or retro- 
grade metamorphosis, or when daughter cells are developed by 
the side of it, the secretion-vesicles separate from the wall of 
the secondary cell, and either float in the cell-juice or sink 
down upon the endogenous cells which are in a state of ab- 
sorbent activity, and in the fluid contents of which new secre- 
tion cells are produced, at first floating in the cell-juice, but 
subsequently adhering to the inner surface of the secondary 
cell-membrane. 
The vesicles in the products of decomposition of the con- 
tents of the mother cell and daughter cells, mentioned at 
p- 30, indicate the occurrence of such a regeneration of the 
secretion-cells, simultaneously with those of the endogenous 
tissue-cells. The vesicles containing chlorophyll, however, can 
never be proved with certainty to be at. the same time con- 
tained in both the mother celi and the daughter cells. Under 
the conditions assumed, it seems to me that they would clothe 
the outer and inner surfaces of the membranes of the daughter 
cells in such a manner as to correspond with each other. 
Moreover some phenomena seem to show that, simalta- 
neously with the absorption of the chlorophyll of the mother 
cell, it is again re-formed in the enlarged daughter cells, which 
completely fill the mother cell (figs. 74 and 76); but these 
do not prove the fact quite satisfactorily. 
Thus, simultaneously with the absorption of the chlorophyll- 
sac over the new septum (fig. 74), a new formation of chloro- 
phyll is perceived near this spot, and, by this, a prolongation 
of the separated extremities is produced, of such a nature that 
the one extremity grows more to the right, and the other more 
to the left at the periphery of the new septum. This newly 
formed chlorophyll is always of a lighter green colour than the 
old sac, and of course does not contain the large starch-vesicles. 
That these are newly formed parts is evident, but it cannot be 
determined whether the appearances are due, as seems probable, 
to the prolongation of a new sac situated within the daughter 
cell beneath the old sac, or to the direct prolongation of the 
partially absorbed sac itself. 
By the action of solution of glycerine or chloride of calcium 
upon cells in course of septum-formation (figs. 74 and 76), 
phenomena are produced very similar to those observed in the 
cell before division (figs. 78 and 79), but very different in their 
nature. 
In the case represented in figs. 78 and 79, the delicate 
