440 Mr. A. Henfrey on the Progress of Physiological Botany : 



inclosed in a membrane. When solutions which act through 

 endosraose 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 bulging of the C. glomerata an opening 

 exists which is almost as wide as the new cell ; in the Yeast the 

 opening is very small. The cell-membrane itself grows forth as 

 in the Conferva glomerata, and the gelatinous contents increase 

 within ; 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 Yeast, 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 different 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 j)rotess of growth may be 

 regarded as directly opposed phaenomena, one being the accumulation of 

 nutrient niatlcr, the other the consumption of it. — A. H. 



