XX V. Observations on Vegetable and Animal Cells ; their Structure, Division, 
and History. By J. M. Macrarzane, B.Sc. (Plate XX XV.) 
Part I.—THE VEGETABLE CELL. 
(Communicated by Professor Dickson.) 
In the present paper I propose exteuding my previous observations ‘“ On the 
Structure and Division of the Vegetable Cell.”* I have shown that a nucleolus 
and nucleolo-nucleus (at Professor Rutherford’s suggestion I now propose terming 
this the endonucleolus) are essential,.and in most cases evident, parts of every 
growing vegetable cell, and that the division of the endonucleolus very probably 
precedes that of the nucleolus, just.as division of the latter undoubtedly pre- 
cedes that of the nucleus, in all the cases investigated. 
Chara fragilis, which I will now specially deal with, is eminently suited, in 
many respects, for confirming the views above stated.. Since all the. tissues are 
produced, directly or indirectly, from.a single apical cell by repeated division, 
the complete life-history of each cell. can pretty easily be ascertained. My 
observations have been made principally on specimens prepared by the. osmic 
acid process. Buds especially, prepared in. this way and. mounted in balsam, 
have a clear appearance and pleasing effect. . 
Bravun,t PrinesHeim,{ Tuuret,§ De Bary,|| Sacus,1 and others, have 
contributed to our knowledge of the history of Chara, while recently Srras- 
BURGER ** and Jonow ft have studied cell.division in it. Reference will be 
made to their results as we proceed. 
In all our recent text-books illustrations of the terminal bud of Chara are 
given with great accuracy, if we deal only with cell wall, protoplasm, and 
nucleus ; but when we come to the nucleolus, appearances are figured such as 
I have never seen in the numerous specimens by me. This is not surprising, if 
we remember that the nucleolus has generally been regarded as a very doubtful 
structure, even in spite of laboured protests in the shape of careful observations 
by NagceELI and others. It will be seen as we advance that in Chara the 
* Trans. Bot. Soe. Edin., vol. xiv. part ii. 
+ Monatsberichte der Berliner Akad. der Wiss., 1852. 
t Jahr. fiir Wiss. Bot. 1864, vol. iii. 
§ Annales des Se. Nat. 1851, vol. xvi. 
|| Monats. der Ber. Akad. 1871. 
J A Text-book of Botany (Eng. ed. 1875). 
** Ueber Zellbildung und Zelltheilung (3rd ed.). 
++ Bot. Zeitung, 1881. 
VOL. XXX. PART II. 42z 
