ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
631 
nucleus suggests tlie possibility of an iron-greening tannin being present 
in the latter. It is doubtful also whether proteids occur in the latex of 
the fig, since its apparent proteid reactions may be due to an iron- 
greening tannin. 
Processes of Aggregation in the Living Cell.* — Dr. P. Klemm 
discusses the phenomena of aggregation which can be induced in the 
living cell, as, for example, in those of the tentacles of Drosera by the 
action of minute quantities of ammonia ; and dissents from Loew at d 
Bokorny’s view j - that it is due to the presence of an “ active albumen.” 
The substances capable of producing this reaction are — in addition to 
ammonia — ammonium carbonate, potassa, soda, organic bases, and neutral 
salts of ammonia and of the organic bases, but not neutral salts of in- 
organic bases. The author maintains that, at least in many cases, the 
excretion of granular bodies in which the phenomenon consists, takes 
place not in the protoplasm but entirely in the cell-sap. In addition to 
albumen, tannin, and lecithin, the author finds phloroglucin present in 
the excreted substances. He concludes that the phenomenon known as 
“ aggregation ” is merely the manifestation of different processes which 
present a similar external appearance. In the majority of cases it is 
clear that tannin plays the principal part in the phenomenon. The 
“ active albumen ” is a purely hypothetical substance. 
In another paper J Dr. Klemm adduces further evidence that in the 
Crassulacese the excretion of granular substance takes place in the cell- 
sap and not in the protoplasm. 
Action of the Nucleole in the Turgidity of Cells. §— M. C. Decagny 
states that in Phaseolus the embryo is enveloped in a close layer of 
endosperm, resting on another layer of endosperm which clothes the 
portion of the embryo-sac below the embryo. In the plane of junction 
of these two layers are a number of very large nuclei with large 
nucleoles ; also a very great number of vesicles ; these latter he asserts 
to be vacuoles of the nucleoles which have escaped from them and have 
entered the nuclear sac. There they have become invested with a solid 
membrane, and have swollen up greatly, finally forming a kind of net- 
work, and causing the well-known turgidity of the nuclei of the endo- 
sperm. 
Transformations of Cellulose. || — M. L. Mangin calls attention to 
the transformation, caused by the action of sulphuric acid or zinc 
chloride, of cellulose into hydrocellulose or amyloid which is coloured 
blue by the action of iodine. He regards hydrocellulose as one of the 
first members of an imperfectly known series resulting from the action 
of these reagents on cellulose. Its production requires a definite decree 
of concentration of the acid. The action of alkalies or of the cupro- 
ammoniacal reagent effects the same change with more certainty. He 
treats in detail of the reactions for cellulose, which he divides into three 
classes: — (1) Iodine reagents; (2) staining reagents of the group 
orseillin BB, in an acid bath ; (3) the series of benzidin reagents, in an 
* Flora, lxxv. (1892) pp. 395-420. f Cf. this Journal, 1890, p. 348. 
+ Ber. Deutsch. Bot. Gesell., x. (1892) pp. 237-42. 
§ Comptes Rendus, cxiv. (1892) pp. 506-7. 
j| Op. cit., cxiii. (1891) pp. 1069-72, 
