74 M. Miiller on the Formation of Starch. 



investigation. Some time elapsed before this opportunity occurred. 

 In the interval the young Chares had become rapidly decomposed 

 and agglomerated, the fruit alone preserving its form. When 

 some of this was placed under the microscope, not only were the 

 contents of the spiral sacs of the spores decomposed, but the sac 

 itself could now easily be dissolved from the nucleus, so that the 

 latter emptied itself of its cells on a little dissection with a knife. 

 I then perceived what I had so long sought for in vain. All the 

 progressive stages of the later cell-development were exposed to 

 view, so that the formation of the starch-granules could be 

 readily perceived by the action of tincture of iodine. The entire 

 result, — the whole mystery of the formation of starch, may be 

 expressed in very few words : it is the cytoblasts which are trans- 

 formed into starch, and this occurs in the mature cells only. 



If there is only one cytoblast in a cell, and this does not con- 

 tain any further cytoblastema, the cytoblast becomes simply ex- 

 panded in all directions until it has reached the circumference of 

 the cell-membrane which surrounds it. It then exhibits an ex- 

 tremely thick dark outline, whence we may conclude that its 

 membrane is tolerably thick. At the same time it is not perfectly 

 homogeneous, but of a granular structure. But when the out- 

 line of the other hemisphere which lies beneath it is examined 

 at the same time, it may be most distinctly perceived that the 

 cytoblast is hollow. This is particularly well seen when it has been 

 coloured very pale blue by tincture of iodine. At the same time 

 we generally perceive within the cytoblasts some more or less 

 roundish and more or less curved granules. This is the simplest 

 case. 



The formation must necessarily become more complex, when 

 in addition to the cytoblast, which is hollowed out and has be- 

 come converted into starch, several other cytoblasts occur. If 

 this happen, the membrane of the primary cell generally becomes 

 very thick in some places, i. e. a granular mass has been depo- 

 sited upon it, which must be considered as cytoblastema, because 

 its structure is of the same granular kind as that of the other 

 parts of Chara (for instance, the cytoblastema between every two 

 cells, from which new cells are formed, consequently in interca- 

 lary growth) and is coloured yellow by iodine. In this mass some 

 portions are heaped up, forming one or several more or less glo- 

 bular groups which become expanded and hollow. They are cy- 

 toblasts which do not however form any solid membrane on their 

 surface, which by its expansion might enlarge so as to form a ho- 

 mogeneous vesicle, as ordinarily occurs in the process of cell- 

 formation. Thus whilst in the latter case a thin layer of the cy- 

 toblast dilates into a homogeneous membrane, in the former the 

 whole mass of the cytoblast is expanded, whence it must neces- 



