440 Mr. A. Henfrey on the Progress of Physiological Botany : 
inclosed in a membrane. When solutions which act through 
endosmose are applied to the cells, these abstract water from the 
gelatinous mass, and the outermost layer, which thus becomes 
the densest, may easily be mistaken for a membrane. The side 
branches are formed by the bulging-out of a cell, and this always 
occurs at the same end in all cells ; thus if we call the end of a 
cell where such a protrusion has occurred, the upper end, it will 
be found at the upper end of all the cells. This bulging portion 
elongates into a cell, and the membrane which produces the di- 
vision is usually formed close to the parent- cell. Sometimes it 
happens that if the parent-cell dies, or the contents have run out 
by a wound, the cell of the lateral branch elongates into the 
parent-cell. 
The formation of the lateral branches by protrusion is of espe- 
cial interest for the explanation of the multiplication of the top- 
Yeast [ober-hefe) ; no formation of cells within cells takes place 
in this. The author has repeatedly observed the whole course 
of the formation of a cell, in Yeast, beneath the microscope, and 
no little cell could ever be seen in the little nodule which first of 
all originates by the bulging-out of the parent-cell ; a small gra- 
nule of the contents of the parent-cell sometimes lay in front of 
the place where the bulging took place, but this never entered 
the young cell. In the l)ulging of the C. glomerata an opening 
exists which is almost as wide as the new cell ; in the Y^east the 
opening is very small. The cell-membrane itself grows forth as 
in the Conferva glomerata, and the gelatinous contents increase 
within j some of this matter can be detected, by means of iodine, 
in the nodule at the very commencement of the protrusion. 
The cells of Yeast are composed of a cell- wall and gelatinous 
contents which become granular, and the granules again consist 
of cell -wall and gelatinous contents, therefore of cells; the cell- 
wall is probably identical with the cuticula of the Confervse ; the 
cellulose layer is wanting in the Y'east, and in the Confervse the 
primordial utricle which H. von Mohl has pointed out in other 
cells does not occur. 
The deposition of starch takes place in the Confervse, as in 
other plants, when the usual process of development in the cell 
is not so active or is hindered, and it ceases when this process be- 
gins again*. 
The remainder of the paper relates to the chemical analyses of 
the difierent portions of the Conferva ; but it will be more inter- 
esting to consider here the relations of the observations brought 
* Starch is not usually formed abundantly in cells until they have ceased 
to grow. Indeed the formation of starch and the process of growth may be 
regarded as directly opposed pluenoniena, one being the accumulation of 
nutrient matter, the other the consumi)tion of it. — A. H. 
