STRUCTURE.] KAEL MULLEK'S VIEWS. 



while in approaching the sides of the section the grains 

 become smaller, and pass gradually into the nature of chlo- 

 rophylle. On directing attention to those parts of the 

 section, in which the cell-contents pass gradually from the 

 state of starch to that of chlorophylle, many cells are seen 

 to contain a distinct nucleated cell, apparently of a flattened 

 or lenticular form, on the edge of which are arranged a 

 number of minute granules; in others the appearances are 

 more advanced, the granules gradually becoming larger, and 

 the nucleated cell becoming obliterated. From the disturb- 

 ance that takes place in the position of the granules after 

 detachment from the nucleated cell, it is difficult to determine 

 by what part they were adherent to it ; but Mr. Quekett 

 believed that this adherence takes place at the end at which 

 the point or hilum is observed. Subsequent to this period the 

 grains of starch enlarge, become laminated, and are multiplied 

 in the manner already pointed out by various observers." 



Karl Muller regards starch grains as a modification of the 

 cytoblast, founding his opinion upon appearances observed in 

 the nucule of Chara crinita in an early stage. He found that 

 in this plant, after long maceration, the kernel of the nucule 

 readily emptied itself of its cells on a little dissection with a 

 knife. He then perceived all the progressive stages of latter 

 cell-development, so that the formation of starch-grains could 

 be readily examined with the aid of tincture of iodine. The 

 result was that cytoblasts are transformed into starch ; but 

 the process occurs in mature cells only. 



" If/' he says, " there is only one cytoblast in a cell, and 

 this does not contain any further cytoblasteme, the cytoblast 

 becomes simply expanded in all directions until it has reached 

 the circumference of the cell-membrane which surrounds it. 

 It then exhibits an extremely 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 outline 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 



