280 Prof. H. Karsten on the Formation, 
Nageli urges, in opposition to the notion of the formation of 
free cells in the fluid contents of a cell laden with various solid 
matters, that changes must have been observable in the solid 
contents adhering to the wall of the mother cells, should these 
become dissolved in the mother cell and afterwards organized 
anew in the daughter cells. 
Well founded as is this supposition of Nageli’s as to the meta- 
morphosis, the notion that such a metamorphosis does not take 
place is equally unfounded. Indeed, in my essay ‘De Cella 
vitali’? (1843, p. 71), and elsewhere, I have maintained the oc- 
currence of those conditions subsequently called in question by 
Nageli, asserting, as a result of my observations, that the secre- 
tion-material contained within the mother cell serves as nutritive 
matter for the ensuing generation. A conviction of the entire 
correctness of this statement, and of its high importance for the 
right understanding of cell-life, may be most readily attained by 
the examination of the species of Gidogonium, which, on account 
of their remarkable tenacity of life (in which they almost equal 
Conferva glomerata), are particularly well adapted for being 
observed continuously under the microscope during the successive 
stages of their process of growth. 
Indeed the entire cell-contents of the joint-cell, which has been 
recently divided in the manner described into two portions, are 
now found interposed between the outer surface of the two 
daughter cells and the inner aspect of the wall of the mother | 
cell. The large, thin-walled, non-nucleated cells (vesicles), filled 
with transparent fluid, existing at the time of the growth of the 
daughter cells, are at this period no longer present ; indeed they 
disappear during the first stage of development of the young 
daughter cells, to which they probably serve as nutritive matter, 
On the contrary, the chlorophyll and the usually large starch- 
granules met with in the different species of Gidogoniwmn, in vari- 
able quantity according to external vital conditions, are rather 
rapidly dissolved during the growth and the thickening of the 
membranous walls of the young joint-cells, in order to supply 
nutritive material for the process of assimilation of the cell-walls 
as well as for the new generation of cells and of secretion-vesi- 
cles in process of formation within the two daughter cells. This 
dissolution of the starch-corpuscles is completed in about twenty- 
four hours. 
The chlorophyll first undergoes this process of absorption, 
and afterwards the large amylaceous corpuscles; and then they 
progressively reappear, but in the opposite order, in the interior 
of the newly formed joint-cells. In the first instance, small 
starch-corpuscles make their appearance, then the chlorophyll- 
vesicles, and, lastly, those large hyaline vesicles which, in the 
