544 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
BOTANY. 
A. GENERAL, including* * * § the Anatomy and Physiology 
of the Phanerogamia. 
a. Anatomy. 
3 i(lX Cell-structure and Protoplasm. 
Influence of the Nucleus on the Formation of Cell-Wall.* — 
Mr. 0. O. Townsend has investigated in a great number of instances the 
mode of formation of the cell- wall, and finds it to be invariably depen- 
dent on the presence of a nucleus. The influence of the nucleus may, 
however, be transmitted from one cell to another in which there is no 
nucleus by connecting strands of protoplasm ; these must be destroyed 
in order to prevent the formation of a cell-wall. The influence may be 
conveyed from cell to cell through the cell-wall. Simple contact without 
continuity of protoplasm does not suffice to produce the result. A cell- 
wall is also formed round the strands of protoplasm. The power of cell- 
wall formation can certainly be transmitted by the protoplasmic strands 
to a distance of several millimetres. Both the nuclei of pollen-tubes 
have the faculty of inciting the formation of cell-wall. 
(2) Other Cell-Contents (including- Secretions). 
“ Encapsuling* ” of Starch-grains.f — Referring to Buscalioni’s state- 
ment on this subject, Prof. L. Macchiati maintains that it rests on 
erroneous observation, careful photographs showing that the alleged 
4t encapsuled ” starch-grains do not belong to the tissue of the testa of 
the seed in question. 
localisation of the Alkaloids in Cinchona.* — According to Dr. J. R. 
Lotsy, in Cinchona calisaya, Ledgeriana, and succirubra , the alkaloids 
occur in the parenchyme, but not in the sieve-tubes. Normally they 
are found only in living cells. Cells which contain calcium oxalate do 
not also contain alkaloid. As a rule, in young organs the alkaloid is 
dissolved in the cell-sap, while in older organs it occurs as a solid 
amorphous mass within the cells. Very active organs, such as the 
cambium or the extreme tip of the growing point, do not usually con- 
tain alkaloid ; while it occurs in large quantities at a short distance 
from these centres. In both leaves and petals the amount of alkaloid 
decreases with age. 
(3) Structure of Tissues. 
Membranes of Vessels.§ — Herr W. Rothert calls attention to the fact 
that in annular, spiral, and reticulated vessels, the thickening bands are 
not, as a rule, attached to the thin membrane of the vessel by their 
greatest breadth, but only by a narrow base. The purpose of this 
* Jahrb. f. wiss. Bot. (Pfeifer u. Strasburger), xxx. (1897) pp. 484-510 (2 pis.). 
■Cf. this Journal, ante, p. 302. 
t Bull. Soc. Bot. I tab, 1897, pp. 178-83. Cf. this Journal, ante, p. 135. 
t Bot. Centralbl., Ixxi. (1897) pp. 395-400. 
§ Anzeig. Acad. Wiss. Krakau, Jan. 1897, 18 pp. See Bot. Centralbl., Ixxi. 
<1897) p. 131. 
