641 
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
characterise the chromosomes while separation of the segments is taking 
place. 
Hypertrophy of the Nucleus caused by a Parasite.* * * § — Sig. F. 
Cavara describes the changes produced in the cells of the root of Vanilla 
plamfolia by a parasitic mycele which attacks the cortical parenchyme. 
The activity of the protoplasm and of the nucleus in these cells is 
increased, the protoplasm becomes granular, while the nucleus in- 
creases greatly in size and exhibits various abnormalities. The effect 
of the parasite is not confined to the cells which it actually attacks, but 
extends also to the neighbouring cells, showing that the irritation is not 
of a purely mechanical, but also of a chemical character. 
Chromatophily of the Nucleus.t — From observations made chiefly 
on the root of the hyacinth, Herr T. Rosen concludes that the ground- 
substance of the nucleus is nucleoplasm ; the nucleoles, cytoplasm, and 
pure cellulose-membrane are erythrophilous, while only certain por- 
tions of the nucleus are cyanopliilous. The substance which fixes the 
blue stain appears to be nuclein. The power of the nuclei to multiply 
goes pari passu with an accumulation of nucleolar substance, the loss of 
this power with its reduction. The old view is not correct, that the 
nucleoles are completely absorbed before the formation of the nuclear 
spindle ; they have seldom entirely disappeared when the very short 
chromosomes have united into the nuclear plate. 
(2) Other Cell-contents (including: Secretions). 
Organic Acids of Mesembryanthemum. J — By the use of new 
chemical methods, MM. Berg and Gerber come to a different conclusion 
from that of Aubert, that the predominant organic acid in Mesembryan - 
themum is oxalic. In M. crystallinum citric and malic acids are present 
in much larger quantities ; in M. linguseforme malic, and in M.perfoliatum 
citric is the predominant acid ; while in M. edule no oxalic acid at all 
could be detected. 
Acid Excretion of Roots. § — Dr. F, Czapek gives a more detailed 
account of his experiments on this subject. The drops often found on 
the root-hairs are the result of pressure from within the hair-cells when 
they are in a turgid condition. The inorganic substances found in them 
are — salts of calcium, potassium, magnesium, hydrochloric acid, sul- 
phuric acid, and phosphoric acid, primary potassium phosphate being 
the most abundant. Acetic and lactic acids were not found in any 
root-excretion, oxalic acid only in that of the hyacinth ; potassium 
formate is not uncommon. The acid salt which takes the greatest share 
in the chemical changes which these excretions bring about in the soil 
is primary potassium phosphate. Diastatic or inverting ferments were 
not detected with certainty. 
* ‘Ipertrofie ed anomalie nucleari in seguito a parassitismo veg.,’ Pavia, 1896, 
8 pp. and 1 pi. See Bot. Centralbl., 1896, Beili., p. 278. 
f JB. Schles. Gesell. Yaterl. Cultur, lxxii. (1895) Zool.-Bot. Sect., pp. 3-10. Cf. 
this Journal, 1895, p. 618. 
X Rev. Ge'n. de Bot. (Bonnier), viii. (1896) pp. 295-303. Cf. this Journal, 1893, 
p. 505. 
§ Jalirb. f. wiss. Bot. (Pfeffer u. Strasburger), xxix. (1896) pp. 321-90. Cf. this 
Journal, ante, p. 432. 
