196 Mr J. M. Macfarlane on the 



nucleus, if the cell is still active. To ascertain, if possible, 

 the function of these, and their role in division of the cell, 

 I set about examining various jjlants. The results obtained 

 have been highly interesting. 



Structure and Division of the Cells o/Ornitliogalum 

 pyramidale, L, ; Scilla bifolia, L. 



Omithogalum 2^y'rO'inn-idale has a much stronger growth 

 than Scilla hifolia, and the cells are very much larger, con- 

 sequently the former has most engaged my attentioQ. By 

 obtaining bulbs in which the young ascending axis had not 

 attained to a great size, and by splitting up these so as to 

 expose the pale actively growing parts, admirable examples 

 were obtained, showing all the stages of cell division. As 

 the epidermis is well suited for study, owing to the large- 

 ness of the cells and their local development of stomata, this 

 tissue has principally been chosen. If we carefully strip 

 off a piece of epidermis, say 2 inches long, from the point 

 of union of a leaf with the short underground axis and 

 upwards, and stain with logwood, iodine, or eosin, all the 

 changes in division and new formation of cells can be traced. 

 At the basal part of the preparation will be seen cells quite 

 resembliug each other in size and structure, and not as 

 yet indicating any differentiation into stoma mother cells, 

 and cells of the epidermis. The interior is generally filled 

 with protoplasm, containing a nucleus, nucleolus, and 

 nucleolo-nucleus. While in many nucleoli only one 

 nucleolo-nucleus is present, others may be seen with two. 

 Some of the nuclei again, as we pass up the preparation, 

 have two nucleoli with a nucleolo-nucleus in each. Lastly, 

 nuclei may be dividing, or nearly divided, to form two cells, 

 each daughter nucleus carrying with it a nucleolus and 

 nucleolo-nucleus. 



One of the two cells thus resulting, we will suppose, 

 elongates to form an epidermal cell, while the other is 

 destined to form a stoma. We will meanwhile trace the 

 latter, superficially distinguished from the former by its 

 increasing little in length, but significantly distinguished 

 by its subsequent history. At first, having only one 

 nucleus, nucleolus, and nucleolo-nucleus, the latter soon 



