ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
79 
BOTANY. 
A. GENERAL, including the Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
(1) Cell-structure and Protoplasm. 
Xaryokinetic Problems.*- Prof. E. Strasburger gives a critical and 
suggestive resume of recent work in vegetable cytology. He discusses the 
behaviour and function of the nucleole during karyokinesis, and confirms 
the statements of other observers as to its frequent fragmentation and 
partial distribution in the cytoplasm at this period. He suggests that it 
provides the material for the construction of the achromatic spindle. T his 
body he considers to consist of two parts — a central strand of unbroken 
fibres, which stretch from pole to pole, and along which the chromo- 
somes slide ; and an outer group of fibres, which end at the equator on 
the chromosomes themselves. These latter fibres are effective in con- 
veying the daughter-chromosomes to their respective poles. He regards 
the SicJiel stage, so often observed daring nuclear divisions of spore- 
mother-cells, as due to the presence of suspended (or dissolved) chromatin 
in the nucleus, which becomes driven up to the nuclear walls by the 
reagents used to fix the cell. He considers that the substances which form 
the chromatin are supplied by the cytoplasm, and confirms the statement 
of Farmer and Belajefff as to the peculiar mode of division of the 
chromosomes in Lilium , but believes that the longitudinal fission for 
the next mitosis is thereby provided for. In a general way, Prof. Stras- 
burger favours the view that the various appearances seen during 
karyokinesis, such as centrosomes, spindle-fibres, and the like, are 
essentially morphological structures, which are definitely referable to 
particular substances or bodies always present in the cell. 
Attachment of Cell-walls4 — M. E. de Wildeman defends, against 
the attacks of Wahrlich and Kny,§ the theory of Errera,[| that a cell- 
membrane, at the moment of its formation, tends to take the same form 
as, under the same conditions, a liquid layer without weight would take. 
The objections of Knv are taken on the ground of examples to which 
the law does not apply, viz. in the case of fresh membranes formed, in 
consequence of injury, in cells long differentiated from the surrounding 
protoplasm. Errera’s law is subject to but few exceptions, and these 
will probably disappear on further examination. 
(2) Other Cell-contents (including- Secretions). 
Reserve-Cellulose in the Seeds of Liliaceae.f — Miss Grace E. Cooley 
has studied the nature of the cellulose in the endosperm of the seeds of 
plants belonging to the Liliaceae and to some other allied orders, with 
the following results : — The endosperm was found to consist, in many 
* Jalirb. f. wiss. Bot (Pfeffer u. Strasburger), xxviii. (1895) pp. 151-201 (2 pis.). 
f Cf. this Journal, 1895, p. 501. 
X Bull Soc. Beige Mieroscopie, xxi. (1895) pp. 81-93. 
§ Cf. this Journal, 1894, pp. 74, 216. || Op. cit., 1S88, p. 555. 
^1 Mem. Boston Soc. Nat. Hist., v. (1895) 29 pp. and 6 pis. 
